Provided by: swaks_20240103.0-2_all 
NAME
Swaks - Swiss Army Knife SMTP, the all-purpose SMTP transaction tester
DESCRIPTION
Swaks' primary design goal is to be a flexible, scriptable, transaction-oriented SMTP test
tool. It handles SMTP features and extensions such as TLS, authentication, and
pipelining; multiple version of the SMTP protocol including SMTP, ESMTP, and LMTP; and
multiple transport methods including UNIX-domain sockets, internet-domain sockets, and
pipes to spawned processes. Options can be specified in environment variables,
configuration files, and the command line allowing maximum configurability and ease of use
for operators and scripters.
QUICK START
Deliver a standard test email to user@example.com on port 25 of test-server.example.net:
swaks --to user@example.com --server test-server.example.net
Deliver a standard test email, requiring CRAM-MD5 authentication as user me@example.com.
An "X-Test" header will be added to the email body. The authentication password will be
prompted for if it cannot be obtained from your .netrc file.
swaks --to user@example.com --from me@example.com --auth CRAM-MD5 --auth-user me@example.com --header-X-Test "test email"
Test a virus scanner using EICAR in an attachment. Don't show the message DATA part.:
swaks -t user@example.com --attach - --server test-server.example.com --suppress-data </path/to/eicar.txt
Test a spam scanner using GTUBE in the body of an email, routed via the MX records for
example.com:
swaks --to user@example.com --body @/path/to/gtube/file
Deliver a standard test email to user@example.com using the LMTP protocol via a UNIX
domain socket file
swaks --to user@example.com --socket /var/lda.sock --protocol LMTP
Report all the recipients in a text file that are non-verifiable on a test server:
for E in `cat /path/to/email/file`
do
swaks --to $E --server test-server.example.com --quit-after RCPT --hide-all
[ $? -ne 0 ] && echo $E
done
TERMS AND CONVENTIONS
This document tries to be consistent and specific in its use of the following terms to
reduce confusion.
Target
The target of a transaction is the thing that Swaks connects to. This generic term is
used throughout the documentation because most other terms improperly imply something
about the transport being used.
Transport
The transport is the underlying method used to connect to the target.
Transaction
A transaction is the opening of a connection over a transport to a target and using a
messaging protocol to attempt to deliver a message.
Protocol
The protocol is the application language used to communicate with the target. This
document uses SMTP to speak generically of all three supported protocols unless it
states that it is speaking of the specific 'SMTP' protocol and excluding the others.
Message
SMTP protocols exist to transfer messages, a set of bytes in an agreed-upon format
that has a sender and a recipient.
Envelope
A message's envelope contains the "true" sender and receiver of a message. It can
also be referred to as its components, envelope-sender and envelope-recipients. It is
important to note that a messages envelope does not have to match its "To:" and
"From:" headers.
DATA
The DATA portion of an SMTP transaction is the actual message that is being
transported. It consists of both the message's headers and its body. DATA and body
are sometimes used synonymously, but they are always two distinct things in this
document.
Headers
A message's headers are defined as all the lines in the message's DATA section before
the first blank line. They contain information about the email that will be displayed
to the recipient such as "To:", "From:", "Subject:", etc. In this document headers
will always be written with a capitalized first letter and a trailing colon.
Body
A message's body is the portion of its DATA section following the first blank line.
Option
An option is a flag which changes Swaks' behavior. Always called an option regardless
of how it is provided. For instance, "--no-data-fixup" is an option.
Argument
When an option takes addition data beside the option itself, that additional data is
called an argument. In "--quit-after <stop-point>'", "<stop-point>" is the argument to
the "--quit-after" option.
<literal-string>
When used in the definition of an option, text that is inside of angle brackets ("<>")
indicates a descriptive label for a value that the user should provide. For instance,
"--quit-after <stop-point>" indicates that "<stop-point>" should be replaced with a
valid stop-point value.
[<optional-value>]
When used in the definition of an option, text inside of square brackets ([])
indicates that the value is optional and can be omitted. For instance, "--to
[<recipient>]" indicates that the "--to" option can be used with or without a
specified "<recipient>".
OPTION PROCESSING
To prevent potential confusion in this document a flag to Swaks is always referred to as
an "option". If the option takes additional data, that additional data is referred to as
an argument to the option. For example, "--from fred@example.com" might be provided to
Swaks on the command line, with "--from" being the option and "fred@example.com" being
"--from"'s argument.
Options and arguments are the only way to provide information to Swaks. If Swaks finds
data during option processing that is neither an option nor an option's argument, it will
error and exit. For instance, if "--no-data-fixup 1" were found on the command line, this
would result in an error because "--no-data-fixup" does not take an argument and therefore
Swaks would not know what to do with 1.
Options can be given to Swaks in three ways. They can be specified in a configuration
file, in environment variables, and on the command line. Depending on the specific option
and whether an argument is given to it, Swaks may prompt the user for the argument.
When Swaks evaluates its options, it first looks for a configuration file (either in a
default location or specified with "--config"). Then it evaluates any options in
environment variables. Finally, it evaluates command line options. At each round of
processing, any options set earlier will be overridden. Additionally, any option can be
prefixed with "no-" to cause Swaks to forget that the variable had previously been set
(either in an earlier round, or earlier in the same round). This capability is necessary
because many options treat defined-but-no-argument differently than not-defined.
As a general rule, if the same option is given multiple time, the last time it is given is
the one that will be used. This applies to both intra-method (if "--from
user1@example.com --from user2@example.com" is given, "user2@example.com" will be used)
and inter-method (if "from user1@example.com" is given in a config file and "--from
user2@example.com" is given on the command line, "user2@example.com" will be used)
Each option definition ends with a parenthetical synopsis of how the option behaves. The
following codes can be used
Arg-None, Arg-Optional, Arg-Required
These three codes are mutually exclusive and describe whether or not the option takes
an argument. Note that this does not necessarily describe whether the argument is
required to be specified directly, but rather whether an argument is required
eventually. For instance, "--to" is labeled as Arg-Required, but it is legal to
specify "--to" on the command line without an argument. This is because Swaks can
prompt for the required argument if it is not directly provided.
From-Prompt
An option labeled with From-Prompt will prompt the user interactively for the argument
if none is provided.
From-File
An option labeled with From-File will handle arguments as files in certain situations.
If the initial argument is "-", the final argument is the contents of "STDIN".
Multiple options can all specify "STDIN", but the same content will be used for each
of them.
If the initial argument is prefixed with "@", the argument will be treated as a path
to a file. The file will be opened and the contents will be used as the final
argument. If the contents of the file can't be read, Swaks will exit. To specify a
literal string value starting with an "@", use two "@" symbols. The first will be
stripped. It is not possible to include an unqualified file which starts with an "@"
sign (like "--attach @file.txt" or "--attach @@file.txt"), but if you include a path
to the file which splits up the two "@" signs, that will work (eg "--attach
@./@file.txt" will include the contents of the file @file.txt).
Sensitive
If an option marked Sensitive attempts to prompt the user for an argument and the
"--protect-prompt" option is set, Swaks will attempt to mask the user input from being
echoed on the terminal. Swaks tries to mask the input in several ways, but if none of
them work program flow will continue with unmasked input.
Deprecated
An option labeled Deprecated has been officially deprecated and will be removed in a
future release. See the "DEPRECATIONS" section of this documentation for details
about the deprecations.
The exact mechanism and format for using each of the types is listed below.
CONFIGURATION FILES
A configuration file can be used to set commonly-used or abnormally verbose options.
By default, Swaks looks in order for $SWAKS_HOME/.swaksrc, $HOME/.swaksrc, and
$LOGDIR/.swaksrc. If one of those is found to exist (and "--config" has not been
used) that file is used as the configuration file.
Additionally, a configuration file in a non-default location can be specified using
"--config". If this is set and not given an argument Swaks will not use any
configuration file, including any default file. If "--config" points to a readable
file, it is used as the configuration file, overriding any default that may exist. If
it points to a non-readable file an error will be shown and Swaks will exit.
A set of "portable" defaults can also be created by adding options to the end of the
Swaks program file. As distributed, the last line of Swaks should be "__END__". Any
lines added after "__END__" will be treated as the contents of a configuration file.
This allows a set of user preferences to be automatically copied from server to server
in a single file.
If configuration files have not been explicitly turned off, the "__END__" config is
always read. Only one other configuration file will ever be used per single
invocation of Swaks, even if multiple configuration files are specified. If the
"__END__" config and another config are to be read, the "__END__" config will be
processed first. Specifying the "--config" option with no argument turns off the
processing of both the "__END__" config and any actual config files.
In a configuration file lines beginning with a hash ("#") are ignored. All other
lines are assumed to be an option to Swaks, with the leading dash or dashes optional.
Everything after an option line's first space is assumed to be the option's argument
and is not shell processed. Therefore, quoting is usually unneeded and will be
included literally in the argument.
There is a subtle difference between providing an option with no argument and
providing an option with an empty argument. If an option line does not have a space,
the entire line is treated as an option and there is no argument. If the line ends in
a single space, it will be processed as an option with an empty argument. So, "apt"
will be treated as "--apt", but "apt " will be treated as "--apt ''".
Here is an example of the contents of a configuration file:
# always use this sender, no matter server or logged in user
--from fred@example.com
# I prefer my test emails have a pretty from header. Note
# the lack of dashes on option and lack of quotes around
# entire argument.
h-From: "Fred Example" <fred@example.com>
Options specific to configuration file:
--config [<config-file>]
This option provides a path to a specific configuration file to be used. If
specified with no argument, no automatically-found configuration file (via $HOME,
etc, or "__END__") will be processed. If the argument is a valid file, that file
will be used as the configuration file (after "__END__" config). If argument is
not a valid, readable file, Swaks will error and exit. This option can be
specified multiple times, but only the first time it is specified (in environment
variable and the command line search order) will be used. (Arg-Optional)
CONFIGURATION ENVIRONMENT VARIABLES
Options can be supplied via environment variables. The variables are in the form
$SWAKS_OPT_name, where "name" is the name of the option that would be specified on the
command line. Because dashes aren't allowed in environment variable names in most
UNIX-ish shells, no leading dashes should be used and any dashes inside the option's
name should be replaced with underscores. The following would create the same options
shown in the configuration file example:
$ SWAKS_OPT_from='fred@example.com'
$ SWAKS_OPT_h_From='"Fred Example" <fred@example.com>'
Setting a variable to an empty value is the same as specifying it on the command line
with no argument. For instance, setting <SWAKS_OPT_server=""> would cause Swaks to
prompt the user for the server to which to connect at each invocation. On Windows, it
is not possible to set empty environment variables. The behavior can be simulated by
setting the environment variable to "<>" instead. Additionally, embedding the header
name in the header option via environment variable is not allowed on Windows (eg
"SWAKS_OPT_header_Foo=bar" will result in an error, but "SWAKS_OPT_header="Foo: bar""
will work.)
Because there is no inherent order in options provided by setting environment
variables, the options are sorted before being processed. This is not a great
solution, but it at least defines the behavior, which would be otherwise undefined.
As an example, if both $SWAKS_OPT_from and $SWAKS_OPT_f were set, the value from
$SWAKS_OPT_from would be used, because it sorts after $SWAKS_OPT_f. Also as a result
of not having an inherent order in environment processing, unsetting options with the
"no-" prefix is unreliable. It works if the option being turned off sorts before
"no-", but fails if it sorts after. Because "no-" is primarily meant to operate
between config types (for instance, unsetting from the command line an option that was
set in a config file), this is not likely to be a problem.
In addition to setting the equivalent of command line options, $SWAKS_HOME can be set
to a directory containing the default .swaksrc to be used.
COMMAND LINE OPTIONS
The final method of supplying options to Swaks is via the command line. The options
behave in a manner consistent with most UNIX-ish command line programs. Many options
have both a short and long form (for instance "-s" and "--server"). By convention
short options are specified with a single dash and long options are specified with a
double-dash. This is only a convention and either prefix will work with either type.
The following demonstrates the example shown in the configuration file and environment
variable sections:
$ swaks --from fred@example.com --h-From: '"Fred Example" <fred@example.com>'
TRANSPORTS
Swaks can connect to a target via UNIX pipes ("pipes"), UNIX domain sockets ("UNIX
sockets"), or internet domain sockets ("network sockets"). Connecting via network sockets
is the default behavior. Because of the singular nature of the transport used, each set
of options in the following section is mutually exclusive. Specifying more than one of
"--server", "--pipe", or "--socket" will result in an error. Mixing other options between
transport types will only result in the irrelevant options being ignored. Below is a
brief description of each type of transport and the options that are specific to that
transport type.
NETWORK SOCKETS
This transport attempts to deliver a message via TCP/IP, the standard method for
delivering SMTP. This is the default transport for Swaks. If none of "--server",
"--pipe", or "--socket" are given then this transport is used and the target server is
determined from the recipient's domain (see "--server" below for more details).
This transport requires the IO::Socket::IP module for both IPv4 and IPv6 sockets. If
this module is not loadable, Swaks will attempt to use the IO::Socket library for IPv4
and IO::Socket::INET6 for IPv6 support. Attempting to use this transport with none of
those libraries available will result in an error and program termination.
The fall back to IO::Socket and IO::Socket::INET6 is deprecated and will be removed in
a future release. See DEPRECATIONS below
-s, --server [<target-server>[:<port>]]
Explicitly tell Swaks to use network sockets and specify the hostname or IP
address to which to connect, or prompt if no argument is given. If this option is
not given and no other transport option is given, the target mail server is
determined from the appropriate DNS records for the domain of the recipient email
address using the Net::DNS module. If Net::DNS is not available Swaks will
attempt to connect to localhost to deliver. The target port can optionally be set
here. Supported formats for this include SERVER:PORT (supporting names and IPv4
addresses); [SERVER]:PORT and SERVER/PORT (supporting names, IPv4 and IPv6
addresses). A port set via this option will only be used if the "--port" option
is not used. See also "--copy-routing". (Arg-Required, From-Prompt)
-p, --port [<port>]
Specify which TCP port on the target is to be used, or prompt if no argument is
listed. The argument can be a service name (as retrieved by getservbyname(3)) or
a port number. The default port is smtp/25 unless influenced by the "--protocol"
or "--tls-on-connect" options. (Arg-Required, From-Prompt)
-li, --local-interface [<local-interface>[:<port>]]
Use argument as the local interface for the outgoing SMTP connection, or prompt
user if no argument given. Argument can be an IP address or a hostname. Default
action is to let the operating system choose the local interface. See "--server"
for additional comments on :<port> format. A port set via this option will only
be used if the "--port" option is not used. (Arg-Required, From-Prompt)
-lp, --local-port, --lport [<port>]
Specify the outgoing port from which to originate the transaction. The argument
can be a service name (as retrieved by getservbyname(3)) or a port number. If
this option is not specified the system will pick an ephemeral port. Note that
regular users cannot specify some ports. (Arg-Required, From-Prompt)
--copy-routing <domain>
The argument is interpreted as the domain part of an email address and it is used
to find the target server using the same logic that would be used to look up the
target server for a recipient email address. See "--to" option for more details
on how the target is determined from the email domain. (Arg-Required)
-4, -6
Force IPv4 or IPv6. (Arg-None)
UNIX SOCKETS
This transport method attempts to deliver messages via a UNIX-domain socket file.
This is useful for testing MTA/MDAs that listen on socket files (for instance, testing
LMTP delivery to Cyrus). This transport requires the IO::Socket::UNIX module which is
part of the standard Perl distribution. If this module is not loadable, attempting to
use this transport will result in an error and program termination.
--socket [<socket-file>]
This option takes as its argument a UNIX-domain socket file. If Swaks is unable
to open this socket it will display an error and exit. (Arg-Required, From-Prompt)
PIPES
This transport attempts to spawn a process and communicate with it via pipes. The
spawned program must be prepared to behave as a mail server over "STDIN"/"STDOUT".
Any MTA designed to operate from inet/xinet should support this. In addition, some
MTAs provide testing modes that can be communicated with via "STDIN"/"STDOUT". This
transport can be used to automate that testing. For example, if you implemented DNSBL
checking with Exim and you wanted to make sure it was working, you could run "swaks
--pipe "exim -bh 127.0.0.2"". Ideally, the process you are talking to should behave
exactly like an SMTP server on "STDIN" and "STDOUT". Any debugging should be sent to
"STDERR", which will be directed to your terminal. In practice, Swaks can generally
handle some debug on the child's "STDOUT", but there are no guarantees on how much it
can handle.
This transport requires the IPC::Open2 module which is part of the standard Perl
distribution. If this module is not loadable, attempting to use this transport will
result in an error and program termination.
--pipe [<command-and-arguments>]
Provide a process name and arguments to the process. Swaks will attempt to spawn
the process and communicate with it via pipes. If the argument is not an
executable Swaks will display an error and exit. (Arg-Required, From-Prompt)
PROTOCOL OPTIONS
These options are related to the protocol layer.
-t, --to [<email-address>[,<email-address>[,...]]]
--cc [<email-address>[,<email-address>[,...]]]
--bcc [<email-address>[,<email-address>[,...]]]
These options all tell Swaks to use the argument(s) as the envelope-recipient for the
email. There are subtle differences between these three options, detailed below. If
any option is specified but with no arguments, Swaks will prompt the user for an
argument.
"--to" is special in that it is the only option required by Swaks. There is no default
value for this option. If no recipients are provided via any means, user will be
prompted to provide one interactively. The only exception to this is if a
"--quit-after" value is provided which will cause the SMTP transaction to be
terminated before the recipient is needed. If multiple recipients are provided and
the recipient domain is needed to determine routing, the domain of the last recipient
in the "--to" argument list is used.
The primary distinction between these options is how their arguments are treated when
generating the DATA portion of the email. They each have their own replacement tokens
("%TO_ADDRESS%", "%CC_ADDRESS%", and "%BCC_ADDRESS%" respectively) which can be used
by anyone crafting a custom DATA. In Swaks' default message, "%TO_ADDRESS%" will be
used for the To: header and, if it is populated, "%CC_HEADER%" will be used for a Cc:
header. "%BCC_ADDRESS%" is not used in the default DATA. (Arg-Required, From-Prompt)
-f, --from [<email-address>]
Use argument as envelope-sender for email, or prompt user if no argument specified.
The string "<>" can be supplied to mean the null sender. If user does not specify a
sender address a default value is used. The domain-part of the default sender is a
best guess at the fully-qualified domain name of the local host. The method of
determining the local-part varies. If the $LOGNAME environment variable is set, it
will be used as the local-part. Otherwise the value from Win32::LoginName() will be
used on Windows and getpwuid(3) on UNIX-ish platforms. See also "--force-getpwuid".
If Swaks cannot determine a local hostname and the sender address is needed for the
transaction, Swaks will error and exit. In this case, a valid string must be provided
via this option. (Arg-Required, From-Prompt)
--ehlo, --lhlo, -h, --helo [<helo-string>]
String to use as argument to HELO/EHLO/LHLO command, or prompt user if no argument is
specified. If this option is not used a best guess at the fully-qualified domain name
of the local host is used. If Swaks cannot determine a local hostname and the helo
string is needed for the transaction, Swaks will error and exit. In this case, a
valid string must be provided via this option. (Arg-Required, From-Prompt)
-q, --quit, --quit-after <stop-point>
Point at which the transaction should be stopped. When the requested stopping point
is reached in the transaction, and provided that Swaks has not errored out prior to
reaching it, Swaks will send "QUIT" and attempt to close the connection cleanly.
These are the valid arguments and notes about their meaning. (Arg-Required)
PROXY
Quit after the server sends a response to a PROXY request. Note that if there is
not an error negotiating proxy, this will be synonymous with CONNECT.
CONNECT, BANNER
Terminate the session after receiving the greeting banner from the target.
FIRST-HELO, FIRST-EHLO, FIRST-LHLO
In a STARTTLS (but not tls-on-connect) session, terminate the transaction after
the first of two HELOs. In a non-STARTTLS transaction, behaves the same as HELO
(see below).
XCLIENT
Quit after XCLIENT is negotiation. This always quits after the point where XCLIENT
would have been negotiated, regardless of whether it was attempted.
XCLIENT-HELO
Quit after the HELO that XCLIENT negotiation triggers. This differs from HELO and
FIRST-HELO because XCLIENT negotiation can happen at multiple points in the SMTP
transaction and it is impossible to specifically refer to the XCLIENT-triggered
HELO using the HELO or FIRST-HELO stop-points. This always quits after the point
where the XCLIENT-triggered HELO would have occurred, regardless of whether it was
attempted.
STARTTLS, TLS
Quit the transaction immediately following TLS negotiation. Note that this
happens in different places depending on whether STARTTLS or tls-on-connect are
used. This always quits after the point where TLS would have been negotiated,
regardless of whether it was attempted.
HELO, EHLO, LHLO
In a STARTTLS or XCLIENT session, quit after the second HELO. Otherwise quit
after the first and only HELO.
AUTH
Quit after authentication. This always quits after the point where authentication
would have been negotiated, regardless of whether it was attempted.
MAIL, FROM
Quit after MAIL FROM: is sent.
RCPT, TO
Quit after RCPT TO: is sent.
--da, --drop-after <stop-point>
The option is similar to "--quit-after", but instead of trying to cleanly shut down
the session it simply terminates the session. This option accepts the same stop-
points as "--quit-after" and additionally accepts DATA and DOT, detailed below. (Arg-
Required)
DATA
Drop the connection after DATA is sent by server.
DOT Drop the connection after the final '.' of the message is sent by server.
--das, --drop-after-send <stop-point>
This option is similar to "--drop-after", but instead of dropping the connection after
reading a response to the stop-point, it drops the connection immediately after
sending stop-point. It accepts the same stop-points as "--drop-after". If the stop-
point is for an optional part of the transaction which is not actually sent (for
instance STARTTLS or AUTH), this option will behave identically to "--drop-after". See
below for specific details. (Arg-Required)
CONNECT
Connect to the server and then drops the connection before receiving the server's
banner.
STARTTLS, TLS
Behaves identically to "--drop-after".
HELO, EHLO, LHLO
Doesn't necessarily work as expected. If it appears to read the HELO response
incorrectly, use FIRST-HELO instead.
--timeout [<time>]
Use argument as the SMTP transaction timeout, or prompt user if no argument given.
Argument can either be a pure digit, which will be interpreted as seconds, or can have
a specifier s, m, or h (5s = 5 seconds, 3m = 180 seconds, 1h = 3600 seconds). As a
special case, 0 means don't timeout the transactions. Default value is 30s. (Arg-
Required, From-Prompt)
--protocol <protocol>
Specify which protocol to use in the transaction. Valid options are shown in the
table below. Currently the 'core' protocols are SMTP, ESMTP, and LMTP. By using
variations of these protocol types one can tersely specify default ports, whether
authentication should be attempted, and the type of TLS connection that should be
attempted. The default protocol is ESMTP. The following table demonstrates the
available arguments to "--protocol" and the options each sets as a side effect. (Arg-
Required)
SMTP
HELO, "-p 25"
SSMTP
EHLO->HELO, "-tlsc -p 465"
SSMTPA
EHLO->HELO, "-a -tlsc -p 465"
SMTPS
HELO, "-tlsc -p 465"
ESMTP
EHLO->HELO, "-p 25"
ESMTPA
EHLO->HELO, "-a -p 25"
ESMTPS
EHLO->HELO, "-tls -p 25"
ESMTPSA
EHLO->HELO, "-a -tls -p 25"
LMTP
LHLO, "-p 24"
LMTPA
LHLO, "-a -p 24"
LMTPS
LHLO, "-tls -p 24"
LMTPSA
LHLO, "-a -tls -p 24"
--pipeline
If the remote server supports it, attempt SMTP PIPELINING (RFC 2920). (Arg-None)
--prdr
If the server supports it, attempt Per-Recipient Data Response (PRDR)
(<https://tools.ietf.org/html/draft-hall-prdr-00.txt>). PRDR is not yet standardized,
but MTAs have begun implementing the proposal. (Arg-None)
--force-getpwuid
Tell Swaks to use the system-default method of determining the current user's username
for the default sender local-part instead of trying $LOGNAME first. Despite the UNIX-
ish-specific option name, this option also works on Windows. (Arg-None)
TLS / ENCRYPTION
These are options related to encrypting the transaction. These have been tested and
confirmed to work with all three transport methods. The Net::SSLeay module is used to
perform encryption when it is requested. If this module is not loadable Swaks will either
ignore the TLS request or error out, depending on whether the request was optional.
STARTTLS is defined as an extension in the ESMTP protocol and will be unavailable if
"--protocol" is set to a variation of plain SMTP. Because it is not defined in the
protocol itself, "--tls-on-connect" is available for any protocol type if the target
supports it.
A local certificate is not required for a TLS connection to be negotiated. However, some
servers use client certificate checking to verify that the client is allowed to connect.
Swaks can be told to use a specific local certificate using the "--tls-cert" and
"--tls-key" options, and optionally to use a certificate chain using the "--tls-chain"
option.
-tls
Require connection to use STARTTLS. Exit if TLS not available for any reason (not
advertised, negotiations failed, etc). (Arg-None)
-tlso, --tls-optional
Attempt to use STARTTLS if available, continue with normal transaction if TLS was
unable to be negotiated for any reason. Note that this is a semi-useless option as
currently implemented because after a negotiation failure the state of the connection
is unknown. In some cases, like a version mismatch, the connection should be left as
plaintext. In others, like a verification failure, the server-side may think that it
should continue speaking TLS while the client thinks it is plaintext. There may be an
attempt to add more granular state detection in the future, but for now just be aware
that odd things may happen with this option if the TLS negotiation is attempted and
fails. (Arg-None)
-tlsos, --tls-optional-strict
Attempt to use STARTTLS if available. Proceed with transaction if TLS is negotiated
successfully or STARTTLS not advertised. If STARTTLS is advertised but TLS
negotiations fail, treat as an error and abort transaction. Due to the caveat noted
above, this is a much saner option than "--tls-optional". (Arg-None)
-tlsc, --tls-on-connect
Initiate a TLS connection immediately on connection. Following common convention, if
this option is specified the default port changes from 25 to 465, though this can
still be overridden with the --port option. (Arg-None)
-tlsp, --tls-protocol <tls-version-specification>
Specify which protocols to use (or not use) when negotiating TLS. At the time of this
writing, the available protocols are sslv2, sslv3, tlsv1, tlsv1_1, tlsv1_2, and
tlsv1_3. The availability of these protocols is dependent on your underlying OpenSSL
library, so not all of these may be available. The list of available protocols is
shown in the output of "--dump" (assuming TLS is available at all).
The specification string is a comma-delimited list of protocols that can be used or
not used. For instance 'tlsv1,tlsv1_1' will only succeed if one of those two
protocols is available on both the client and the server. Conversely,
'no_sslv2,no_sslv3' will attempt to negotiate any protocol except sslv2 and sslv3.
The two forms of specification cannot be mixed. (Arg-Required)
--tls-cipher <cipher-string>
The argument to this option is passed to the underlying OpenSSL library to set the
list of acceptable ciphers to the be used for the connection. The format of this
string is opaque to Swaks and is defined in
<https://www.openssl.org/docs/manmaster/man1/openssl-ciphers.html#CIPHER-LIST-FORMAT>.
A brief example would be "--tls-cipher '3DES:+RSA'". (Arg-Required)
--tls-verify
Tell Swaks to attempt to verify the server's certificate. This option is identical to
specifying both the "--tls-verify-ca" and "--tls-verify-host" options. See those
options for detailed descriptions of how to fine-tune each type of verification.
By default, TLS verification is not required. If TLS verification is required by
"--tls-verify", "--tls-verify-ca", or "--tls-verify-host" and the requested type of
verification fails, TLS negotiation will not succeed. (Arg-None)
--tls-verify-ca
Require that the server's certificate be signed by a known certificate authority and
not be expired. By default the list of known CAs will be whatever is available via
the client Swaks is running on. To provide a custom CA, see "--tls-ca-path". (Arg-
None)
--tls-verify-host
Require that the target of the current connection be listed in the server
certificate's Subject Alternative Name (SAN) or Subject CommonName (CN).
The target that Swaks uses for verification will vary. It can be a hostname, either
provided directly via the "--server" option or looked up via MX records. In this
case, verification performs as expected. If the target is an IP, the IP will be
looked up in the certificate, which is possible but unusual. If the transport is
"--pipe" or "--socket", there will not be a meaningful target to verify in the
certificate and verification will fail. In this situation it's better to use only
"--tls-verify-ca" or to override the target used for verification with the
"--tls-verify-target" option. (Arg-None)
--tls-verify-target <verification-string>
When set, the argument to this option will be used as the host to be verified for
"--tls-verify-host". This is necessary when using "--tls-verify-host" with either the
"--pipe" or "--socket" transports, which do not have a verifiable target by default.
It can also be used to override the default target lookup when using the "--server"
transport. For instance, it can be used to verify that the certificate of a server
explicitly connect to via IP contains a specific certificate. (Arg-Required)
--tls-ca-path <ca-location>
Specify an alternate location for CA information for verifying server certificates.
The argument can point to a file or directory. The default behavior is to use the
underlying OpenSSL library's default information. (Arg-Required)
--tls-cert <cert-file>
Provide a path to a file containing the local certificate Swaks should use if TLS is
negotiated. If a certificate chain needs to be provided, it can be provided via this
file or via a separate file with "--tls-chain". The file path argument is required.
As currently implemented the certificate in the file must be in PEM format. Contact
the author if there's a compelling need for ASN1. If this option is set, "--tls-key"
is also required. (Arg-Required)
--tls-key <key-file>
Provide a path to a file containing the local private key Swaks should use if TLS is
negotiated. The file path argument is required. As currently implemented the
certificate in the file must be in PEM format. Contact the author if there's a
compelling need for ASN1. If this option is set, "--tls-cert" is also required. (Arg-
Required)
--tls-chain <chain-file>
Provide a path to a file containing the local certificate chain Swaks should use if
TLS is negotiated. The file path argument is required. As currently implemented the
certificate in the file must be in PEM format. Contact the author if there's a
compelling need for ASN1. If this option is set, "--tls-cert" and "--tls-key" are
also required. (Arg-Required)
--tls-get-peer-cert [<output-file>]
Get a copy of the TLS peer's certificate. If no argument is given, it will be
displayed to "STDOUT". If an argument is given it is assumed to be a filesystem path
specifying where the certificate should be written. The saved certificate can then be
examined using standard tools such as the openssl command. If a file is specified its
contents will be overwritten. This option will only ever return one certificate. In
order to get every certificate sent by the server, see "--tls-get-peer-chain". (Arg-
Optional)
--tls-get-peer-chain [<output-file>]
Get a copy of the TLS certificate chain sent by the server. If no argument is given,
it will be displayed to "STDOUT". If an argument is given it is assumed to be a
filesystem path specifying where the certificate should be written. The saved chain
can then be examined using standard tools such as the openssl command. If a file is
specified its contents will be overwritten. See also "--tls-get-peer-cert". (Arg-
Optional)
--tls-sni <sni-string>
Specify the Server Name Indication field to send when the TLS connection is initiated.
(Arg-Required)
AUTHENTICATION
Swaks will attempt to authenticate to the target mail server if instructed to do so. This
section details available authentication types, requirements, options and their
interactions, and other fine points in authentication usage. Because authentication is
defined as an extension in the ESMTP protocol it will be unavailable if "--protocol" is
set to a variation of SMTP.
All authentication methods require base64 encoding. If the MIME::Base64 Perl module is
loadable Swaks attempts to use it to perform these encodings. If MIME::Base64 is not
available Swaks will use its own onboard base64 routines. These are slower than the
MIME::Base64 routines and less reviewed, though they have been tested thoroughly. Using
the MIME::Base64 module is encouraged.
If authentication is required (see options below for when it is and isn't required) and
the requirements aren't met for the authentication type available, Swaks displays an error
and exits. Two ways this can happen include forcing Swaks to use a specific
authentication type that Swaks can't use due to missing requirements, or allowing Swaks to
use any authentication type, but the server only advertises types Swaks can't support. In
the former case Swaks errors out at option processing time since it knows up front it
won't be able to authenticate. In the latter case Swaks will error out at the
authentication stage of the SMTP transaction since Swaks will not be aware that it will
not be able to authenticate until that point.
Following are the supported authentication types including any individual notes and
requirements.
The following options affect Swaks' use of authentication. These options are all inter-
related. For instance, specifying "--auth-user" implies "--auth" and "--auth-password".
Specifying "--auth-optional" implies "--auth-user" and "--auth-password", etc.
-a, --auth [<auth-type>[,<auth-type>[,...]]]
Require Swaks to authenticate. If no argument is given, any supported auth-types
advertised by the server are tried until one succeeds or all fail. If one or more
auth-types are specified as an argument, each that the server also supports is tried
in order until one succeeds or all fail. This option requires Swaks to authenticate,
so if no common auth-types are found or no credentials succeed, Swaks displays an
error and exits. (Arg-Optional)
The following tables lists the valid auth-types
LOGIN, PLAIN
These basic authentication types are fully supported and tested and have no
additional requirements
CRAM-MD5
The CRAM-MD5 authenticator requires the Digest::MD5 module. It is fully tested
and believed to work against any server that implements it.
DIGEST-MD5
The DIGEST-MD5 authenticator (RFC2831) requires the Authen::SASL module. Version
20100211.0 and earlier used Authen::DigestMD5 which had some protocol level errors
which prevented it from working with some servers. Authen::SASL's DIGEST-MD5
handling is much more robust.
The DIGEST-MD5 implementation in Swaks is fairly immature. It currently supports
only the "auth" qop type, for instance. If you have DIGEST-MD5 experience and
would like to help Swaks support DIGEST-MD5 better, please get in touch with me.
The DIGEST-MD5 protocol's "realm" value can be set using the "--auth-extra"
"realm" keyword. If no realm is given, a reasonable default will be used.
The DIGEST-MD5 protocol's "digest-uri" values can be set using the "--auth-extra"
option. For instance, you could create the digest-uri-value of
"lmtp/mail.example.com/example.com" with the option "--auth-extra
dmd5-serv-type=lmtp,dmd5-host=mail.example.com,dmd5-serv-name=example.com". The
"digest-uri-value" string and its components is defined in RFC2831. If none of
these values are given, reasonable defaults will be used.
CRAM-SHA1
The CRAM-SHA1 authenticator requires the Digest::SHA module. This type has only
been tested against a non-standard implementation on an Exim server and may
therefore have some implementation deficiencies.
NTLM/SPA/MSN
These authenticators require the Authen::NTLM module. This type has been tested
against Exim, Communigate, and Exchange 2007.
In addition to the standard username and password, this authentication type can
also recognize a "domain". The domain can be set using the "--auth-extra"
"domain" keyword. Note that this has never been tested with a mail server that
doesn't ignore DOMAIN so this may be implemented incorrectly.
-ao, --auth-optional [<auth-type>[,<auth-type>[,...]]]
This option behaves identically to "--auth" except that it requests authentication
rather than requiring it. If no common auth-types are found or no credentials
succeed, Swaks proceeds as if authentication had not been requested. (Arg-Optional)
-aos, --auth-optional-strict [<auth-type>[,<auth-type>[,...]]]
This option is a compromise between "--auth" and "--auth-optional". If authentication
is never attempted (server doesn't advertise authentication or no common
authentication types are found), it behaves like "--auth-optional" and the smtp
transaction continues. If authentication is attempted but fails, it behaves like
"--auth" and exits with an error. (Arg-Optional)
-au, --auth-user [<username>]
Provide the username to be used for authentication. If no username is provided,
indicate that Swaks should attempt to find the username via .netrc (requires the
Net::Netrc module). If no username is provided and cannot be found via .netrc, the
user will be prompted to provide one. The string "<>" can be supplied to mean an
empty username. (Arg-Required, From-Prompt)
-ap, --auth-password [<password>]
Provide the password to be used for authentication. If no password is provided,
indicate that Swaks should attempt to find the password via .netrc (requires the
Net::Netrc module). If no password is provided and cannot be found via .netrc, the
user will be prompted to provide one. The string "<>" can be supplied to mean an
empty password. (Arg-Required, From-Prompt, Sensitive)
-ae, --auth-extra <key-value-pair>[,<key-value-pair>[,...]]
Some of the authentication types allow extra information to be included in the
authentication process. Rather than add a new option for every nook and cranny of
each authenticator, the "--auth-extra" option allows this information to be supplied.
The format for <key-value-pair> is KEYWORD=VALUE. (Arg-Required)
The following table lists the currently recognized keywords and the authenticators
that use them
realm, domain
The realm and domain keywords are synonymous. Using either will set the "domain"
option in NTLM/MSN/SPA and the "realm" option in DIGEST-MD5
dmd5-serv-type
The dmd5-serv-type keyword is used by the DIGEST-MD5 authenticator and is used, in
part, to build the digest-uri-value string (see RFC2831)
dmd5-host
The dmd5-host keyword is used by the DIGEST-MD5 authenticator and is used, in
part, to build the digest-uri-value string (see RFC2831)
dmd5-serv-name
The dmd5-serv-name keyword is used by the DIGEST-MD5 authenticator and is used, in
part, to build the digest-uri-value string (see RFC2831)
-am, --auth-map <key-value-pair>[,<key-value-pair>[,...]]
Provides a way to map alternate names onto base authentication types. Useful for any
sites that use alternate names for common types. The format for <key-value-pair> is
AUTH-ALIAS=AUTH-TYPE. This functionality is actually used internally to map types SPA
and MSN onto the base type NTLM. The command line argument to simulate this would be
"--auth-map SPA=NTLM,MSN=NTLM". All of the auth-types listed above are valid targets
for mapping except SPA and MSN. (Arg-Required)
-apt, --auth-plaintext
Instead of showing AUTH strings base64 encoded as they are transmitted, translate them
to plaintext before printing on screen. (Arg-None)
-ahp, --auth-hide-password [<replacement-string>]
If this option is specified, any time a readable password would be printed to the
terminal (specifically AUTH PLAIN and AUTH LOGIN) the password is replaced with the
string 'PROVIDED_BUT_REMOVED' (or the contents of <replacement-string> if provided).
The dummy string may or may not be base64 encoded, contingent on the
"--auth-plaintext" option.
Note that "--auth-hide-password" is similar, but not identical, to the
"--protect-prompt" option. The former protects passwords from being displayed in the
SMTP transaction regardless of how they are entered. The latter protects sensitive
strings when the user types them at the terminal, regardless of how the string would
be used. (Arg-Optional)
XCLIENT OPTIONS
XCLIENT is an SMTP extension introduced by the Postfix project. XCLIENT allows a
(properly-authorized) client to tell a server to use alternate information, such as IP
address or hostname, for the client. This allows much easier paths for testing mail
server configurations. Full details on the protocol are available at
<http://www.postfix.org/XCLIENT_README.html>.
The XCLIENT verb can be passed to the server multiple times per SMTP session with
different attributes. For instance, HELO and PROTO might be passed in one call and NAME
and ADDR passed in a second. Because it can be useful for testing, Swaks exposes some
control over how the attributes are grouped and in what order they are passed to the
server. The different options attempt to expose simplicity for those using Swaks as a
client, and complexity for those using Swaks to test installs.
--xclient-addr [<string>]
--xclient-name [<string>]
--xclient-port [<string>]
--xclient-proto [<string>]
--xclient-destaddr [<string>]
--xclient-destport [<string>]
--xclient-helo [<string>]
--xclient-login [<string>]
--xclient-reverse-name [<string>]
These options specify XCLIENT attributes that should be sent to the target server. If
<string> is not provided, Swaks will prompt and read the value on "STDIN". See
<http://www.postfix.org/XCLIENT_README.html> for official documentation for what the
attributes mean and their possible values, including the special "[UNAVAILABLE]" and
"[TEMPUNAVAIL]" values.
By way of simple example, setting "--xclient-name foo.example.com --xclient-addr
192.168.1.1" will cause Swaks to send the SMTP command "XCLIENT NAME=foo.example.com
ADDR=192.168.1.1".
Note that the "REVERSE_NAME" attribute doesn't seem to appear in the official
documentation. There is a mailing list thread that documents it, viewable at
<http://comments.gmane.org/gmane.mail.postfix.user/192623>.
These options can all be mixed with each other, and can be mixed with the "--xclient"
option (see below). By default all attributes will be combined into one XCLIENT call,
but see "--xclient-delim". (Arg-Required, From-Prompt)
--xclient-delim
When this option is specified, it indicates a break in XCLIENT attributes to be sent.
For instance, setting "--xclient-helo 'helo string' --xclient-delim --xclient-name
foo.example.com --xclient-addr 192.168.1.1" will cause Swaks to send two XCLIENT
calls, "XCLIENT HELO=helo+20string" and "XCLIENT NAME=foo.example.com
ADDR=192.168.1.1". This option is ignored where it doesn't make sense (at the start
or end of XCLIENT options, by itself, consecutively, etc). (Arg-None)
--xclient [<string>]
This is the "free form" XCLIENT option. Whatever value is provided for <string> will
be sent verbatim as the argument to the XCLIENT SMTP command. For example, if
"--xclient 'NAME= ADDR=192.168.1.1 FOO=bar'" is used, Swaks will send the SMTP command
"XCLIENT NAME= ADDR=192.168.1.1 FOO=bar". If no argument is passed on command line,
Swaks will prompt and read the value on STDIN.
The primary advantage to this over the more specific options above is that there is no
XCLIENT syntax validation here. This allows you to send invalid XCLIENT to the target
server for testing. Additionally, at least one MTA (Message Systems' Momentum,
formerly ecelerity) implements XCLIENT without advertising supported attributes. The
"--xclient" option allows you to skip the "supported attributes" check when
communicating with this type of MTA (though see also "--xclient-no-verify").
The "--xclient" option can be mixed freely with the "--xclient-*" options above. The
argument to "--xclient" will be sent in its own command group. For instance, if
"--xclient-addr 192.168.0.1 --xclient-port 26 --xclient 'FOO=bar NAME=wind'" is given
to Swaks, "XCLIENT ADDR=192.168.0.1 PORT=26" and "XCLIENT FOO=bar NAME=wind" will both
be sent to the target server. (Arg-Required, From-Prompt)
--xclient-no-verify
Do not enforce the requirement that an XCLIENT attribute must be advertised by the
server in order for Swaks to send it in an XCLIENT command. This is to support
servers which don't advertise the attributes but still support them. (Arg-None)
--xclient-before-starttls
If Swaks is configured to attempt both XCLIENT and STARTTLS, it will do STARTTLS
first. If this option is specified it will attempt XCLIENT first. (Arg-None)
--xclient-optional
--xclient-optional-strict
In normal operation, setting one of the "--xclient*" options will require a successful
XCLIENT transaction to take place in order to proceed (that is, XCLIENT needs to be
advertised, all the user-requested attributes need to have been advertised, and the
server needs to have accepted Swaks' XCLIENT request). These options change that
behavior. "--xclient-optional" tells Swaks to proceed unconditionally past the
XCLIENT stage of the SMTP transaction, regardless of whether it was successful.
"--xclient-optional-strict" is similar but more granular. The strict version will
continue to XCLIENT was not advertised, but will fail if XCLIENT was attempted but did
not succeed. (Arg-None)
PROXY OPTIONS
Swaks implements the Proxy protocol as defined in
<http://www.haproxy.org/download/1.5/doc/proxy-protocol.txt>. Proxy allows an application
load balancer, such as HAProxy, to be used in front of an MTA while still allowing the MTA
access to the originating host information. Proxy support in Swaks allows direct testing
of an MTA configured to expect requests from a proxy, bypassing the proxy itself during
testing.
Swaks makes no effort to ensure that the Proxy options used are internally consistent.
For instance, "--proxy-family" (in version 1) is expected to be one of "TCP4" or "TCP6".
While it will likely not make sense to the target server, Swaks makes no attempt to ensure
that "--proxy-source" and "--proxy-dest" are in the same protocol family as
"--proxy-family" or each other.
The "--proxy" option is mutually exclusive with all other "--proxy-*" options except
"--proxy-version".
When "--proxy" is not used, all of "--proxy-family", "--proxy-source",
"--proxy-source-port", "--proxy-dest", and "--proxy-dest-port" are required.
Additionally, when "--proxy-version" is 2, "--proxy-protocol" and "--proxy-command" are
optional.
--proxy-version [ 1 | 2 ]
Whether to use version 1 (human readable) or version 2 (binary) of the Proxy protocol.
Version 1 is the default. Version 2 is only implemented through the "address block",
and is roughly on par with the information provided in version 1. (Arg-Required, From-
Prompt)
--proxy [<string>]
This option provides the raw proxy string which will be sent to the server. The
protocol prefix ("PROXY " for version 1, the 12-byte protocol header for version 2)
can be present or not in the argument. This option allows sending incomplete or
malformed Proxy strings to a target server for testing. This option is mutually
exclusive with all other "--proxy-*" options which provide granular proxy information.
Because version 2 of the Proxy protocol is a binary protocol, there are multiple ways
to provide the argument to this option. If the argument starts with "base64:", that
prefix is stripped and the rest of the string is base64 decoded before use. If the
argument starts with "@" it will be treated as a filename and the proxy value will be
read from the file. Any other value is assumed to be the literal value for the proxy
string. (Arg-Required, From-Prompt, From-File)
--proxy-family [<string>]
For version 1, specifies both the address family and transport protocol. The protocol
defines TCP4 and TCP6.
For version 2, specifies only the address family. The protocol defines AF_UNSPEC,
AF_INET, AF_INET6, and AF_UNIX. (Arg-Required, From-Prompt)
--proxy-protocol [<string>]
For version 2, specifies the transport protocol. The protocol defines UNSPEC, STREAM,
and DGRAM. The default is STREAM. This option is unused in version 1. (Arg-Required,
From-Prompt)
--proxy-command [<string>]
For version 2, specifies the transport protocol. The protocol defines LOCAL and
PROXY. The default is PROXY. This option is unused in version 1. (Arg-Required,
From-Prompt)
--proxy-source [<string>]
Specify the source address of the proxied connection. (Arg-Required, From-Prompt)
--proxy-source-port [<string>]
Specify the source port of the proxied connection. (Arg-Required, From-Prompt)
--proxy-dest [<string>]
Specify the destination address of the proxied connection. (Arg-Required, From-Prompt)
--proxy-dest-port [<string>]
Specify the destination port of the proxied connection. (Arg-Required, From-Prompt)
DATA OPTIONS
These options pertain to the contents for the DATA portion of the SMTP transaction. By
default a very simple message is sent. If the "--attach" or "--attach-body" options are
used, Swaks attempts to upgrade to a MIME message.
-d, --data [<data-portion>]
Use argument as the entire contents of DATA.
If no argument is provided, user will be prompted to supply value.
If the argument "-" is provided the data will be read from "STDIN" with no prompt.
If the argument starts with "@" it will be treated as a filename. If you would like
to pass in an argument that starts with "@" and isn't a filename, prefix the argument
with an additional "@". For example, "@file.txt" will force processing of file.txt.
@@data will use the string '@data'.
If the argument does not contain any literal (0x0a) or representative (0x5c, 0x6e or
%NEWLINE%) newline characters, it will be treated as a filename. If the file is open-
able, the contents of the file will be used as the data portion. If the file cannot
be opened, Swaks will error and exit. The entire behavior described in this paragraph
is deprecated and will be removed in a future release. Instead use a leading "@" to
explicitly set that the argument is a filename.
Any other argument will be used as the DATA contents.
The value can be on one single line, with "\n" (ASCII 0x5c, 0x6e) representing where
line breaks should be placed. Leading dots will be quoted. Closing dot is not
required but is allowed. The default value for this option is "Date: %DATE%\nTo:
%TO_ADDRESS%\nFrom: %FROM_ADDRESS%\nSubject: test %DATE%\nMessage-Id:
<%MESSAGEID%>\nX-Mailer: swaks v%SWAKS_VERSION%
jetmore.org/john/code/swaks/\n%NEW_HEADERS%\n%BODY%\n".
Very basic token parsing is performed on the DATA portion. The following table shows
the recognized tokens and their replacement values. (Arg-Required, From-Prompt, From-
File)
%FROM_ADDRESS%, ..FROM_ADDRESS..
Replaced with the envelope-sender.
%TO_ADDRESS%, ..TO_ADDRESS..
Replaced with the envelope-recipient(s) set by the "--to" option.
%CC_ADDRESS%, ..CC_ADDRESS..
Replaced with the envelope-recipient(s) set by the "--cc" option.
%BCC_ADDRESS%, ..BCC_ADDRESS..
Replaced with the envelope-recipient(s) set by the "--bcc" option.
%DATE%, ..DATE..
Replaced with the current time in a format suitable for inclusion in the Date:
header. Note this attempts to use the standard module POSIX for timezone
calculations. If this module is unavailable or the current environment doesn't
support the %z strftime format token (as on Windows) the date string will be in
GMT.
%MESSAGEID%, ..MESSAGEID..
Replaced with a message ID string suitable for use in a Message-Id header. The
value for this token will remain consistent for the life of the process.
%SWAKS_VERSION%, ..SWAKS_VERSION..
Replaced with the version of the currently-running Swaks process.
%NEW_HEADERS%, ..NEW_HEADERS..
Replaced with the contents of the "--add-header" option. If "--add-header" is not
specified this token is simply removed.
%BODY%, ..BODY..
Replaced with the value specified by the "--body" option. See "--body" for
default.
%NEWLINE%, ..BODY..
Replaced with carriage return, newline (0x0d, 0x0a). This is identical to using
"\n" (0x5c, 0x6e), but doesn't have the escaping concerns that the backslash can
cause on the newline.
-dab, --dump-as-body [<section>[,<section>[,...]]]
If "--dump-as-body" is used and no other option is used to change the default body of
the message, the body is replaced with output similar to the output of what is
provided by "--dump". "--dump"'s initial program capability stanza is not displayed,
and the "data" section is not included. Additionally, "--dump" always includes
passwords. By default "--dump-as-body" does not include passwords, though this can be
changed with "--dump-as-body-shows-password". "--dump-as-body" takes the same
arguments as "--dump" except the SUPPORT and DATA arguments are not supported. (Arg-
Optional)
-dabsp, --dump-as-body-shows-password
Cause "--dump-as-body" to include plaintext passwords. This option is not
recommended. This option implies "--dump-as-body". (Arg-None)
--body [<body-specification>]
Specify the body of the email. The default is "This is a test mailing". If no
argument to "--body" is given, prompt to supply one interactively. If "-" is
supplied, the body will be read from standard input. Arguments beginning with "@"
will be treated as filenames containing the body data to use (see "--data" for more
detail).
If, after the above processing, the argument represents an open-able file, the content
of that file is used as the body. This is deprecated behavior and will be removed in
a future release. Instead use a leading "@" to explicitly set that the argument is a
filename.
If the message is forced to MIME format (see "--attach") "--body 'body text'" is the
same as "--attach-type text/plain --attach-body 'body text'". See "--attach-body" for
details on creating a multipart/alternative body. (Arg-Required, From-Prompt, From-
File)
--attach [<attachment-specification>]
When one or more "--attach" option is supplied, the message is changed into a
multipart/mixed MIME message. The arguments to "--attach" are processed the same as
"--body" with respect to "STDIN", file contents, etc. "--attach" can be supplied
multiple times to create multiple attachments. By default, each attachment is
attached as an application/octet-stream file. See "--attach-type" for changing this
behavior.
If the contents of the attachment are provided via a file name, the MIME encoding will
include that file name. See "--attach-name" for more detail on file naming.
It is legal for "-" ("STDIN") to be specified as an argument multiple times (once for
"--body" and multiple times for "--attach"). In this case, the same content will be
attached each time it is specified. This is useful for attaching the same content
with multiple MIME types. (Arg-Required, From-File)
--attach-body [<body-specification>]
This is a variation on "--attach" that is specifically for the body part of the email.
It behaves identically to "--attach" in that it takes the same arguments and forces
the creation of a MIME message. However, it is different in that the argument will
always be the first MIME part in the message, no matter where in option processing
order it is encountered. Additionally, "--attach-body" options stack to allow
creation of multipart/alternative bodies. For example, "--attach-type text/plain
--attach-body 'plain text body' --attach-type text/html --attach-body 'html body'"
would create a multipart/alternative message body. (Arg-Required, From-File)
--attach-type <mime-type>
By default, content that gets MIME attached to a message with the "--attach" option is
encoded as application/octet-stream (except for the body, which is text/plain by
default). "--attach-type" changes the mime type for every "--attach" option which
follows it. It can be specified multiple times. The current MIME type gets reset to
application/octet-stream between processing body parts and other parts. (Arg-Required)
--attach-name [<name>]
This option sets the filename that will be included in the MIME part created for the
next "--attach" option. If no argument is set for this option, it causes no filename
information to be included for the next MIME part, even if Swaks could generate it
from the local file name. (Arg-Optional)
-ah, --add-header <header>
This option allows headers to be added to the DATA. If "%NEW_HEADERS%" is present in
the DATA it is replaced with the argument to this option. If "%NEW_HEADERS%" is not
present, the argument is inserted between the first two consecutive newlines in the
DATA (that is, it is inserted at the end of the existing headers).
The option can either be specified multiple times or a single time with multiple
headers separated by a literal "\n" string. So, "--add-header 'Foo: bar' --add-header
'Baz: foo'" and "--add-header 'Foo: bar\nBaz: foo'" end up adding the same two
headers. (Arg-Required)
--header <header-and-data>, --h-<header> <data>
These options allow a way to change headers that already exist in the DATA. "--header
'Subject: foo'" and "--h-Subject foo" are equivalent. If the header does not already
exist in the data then this argument behaves identically to "--add-header". However,
if the header already exists it is replaced with the one specified. Negating the
version of this option with the header name in the option (eg "--no-header-Subject")
will remove all previously processed "--header" options, not just the ones used for
'Subject'. Embedding the header name in the option via environment variable is not
supported on Windows and will result in an error. (Arg-Required)
-g This option is a direct alias to "--data -" (read DATA from "STDIN"). It is totally
secondary to "--data". Any occurrence of "--data" will cause "-g" to be ignored.
This option cannot be negated with the "no-" prefix. This option is deprecated and
will be removed in a future version of Swaks. (Arg-None, Deprecated)
--no-data-fixup, -ndf
This option forces Swaks to do no massaging of the DATA portion of the email. This
includes token replacement, From_ stripping, trailing-dot addition,
"--body"/attachment inclusion, and any header additions. This option is only useful
when used with "--data", since the internal default DATA portion uses tokens. (Arg-
None)
--no-strip-from, -nsf
Don't strip the From_ line from the DATA portion, if present. (Arg-None)
OUTPUT OPTIONS
Swaks provides a transcript of its transactions to its caller ("STDOUT"/"STDERR") by
default. This transcript aims to be as faithful a representation as possible of the
transaction though it does modify this output by adding informational prefixes to lines
and by providing plaintext versions of TLS transactions
The "informational prefixes" are referred to as transaction hints. These hints are
initially composed of those marking lines that are output of Swaks itself, either
informational or error messages, and those that indicate a line of data actually sent or
received in a transaction. This table indicates the hints and their meanings:
"==="
Indicates an informational line generated by Swaks.
"***"
Indicates an error generated within Swaks.
" ->"
Indicates an expected line sent by Swaks to target server.
" ~>"
Indicates a TLS-encrypted, expected line sent by Swaks to target server.
"**>"
Indicates an unexpected line sent by Swaks to the target server.
"*~>"
Indicates a TLS-encrypted, unexpected line sent by Swaks to target server.
" >"
Indicates a raw chunk of text sent by Swaks to a target server (see
"--show-raw-text"). There is no concept of "expected" or "unexpected" at this level.
"<- "
Indicates an expected line sent by target server to Swaks.
"<~ "
Indicates a TLS-encrypted, expected line sent by target server to Swaks.
"<**"
Indicates an unexpected line sent by target server to Swaks.
"<~*"
Indicates a TLS-encrypted, unexpected line sent by target server to Swaks.
"< "
Indicates a raw chunk of text received by Swaks from a target server (see
"--show-raw-text"). There is no concept of "expected" or "unexpected" at this level.
The following options control what and how output is displayed to the caller.
-n, --suppress-data
Summarizes the DATA portion of the SMTP transaction instead of printing every line.
This option is very helpful, bordering on required, when using Swaks to send certain
test emails. Emails with attachments, for instance, will quickly overwhelm a terminal
if the DATA is not suppressed. (Arg-None)
-stl, --show-time-lapse [i]
Display time lapse between send/receive pairs. This option is most useful when
Time::HiRes is available, in which case the time lapse will be displayed in
thousandths of a second. If Time::HiRes is unavailable or "i" is given as an argument
the lapse will be displayed in integer seconds only. (Arg-Optional)
Don't display the transaction hint for informational transactions. This is most
useful when needing to copy some portion of the informational lines, for instance the
certificate output from "--tls-get-peer-cert". (Arg-None)
-nih, --no-info-hints
-nsh, --no-send-hints
-nrh, --no-receive-hints
-nth, --no-hints
"--no-info-hints", "--no-send-hints", and "--no-receive-hints" suppress the
transaction hints from info, send, and receive lines, respectively. This is often
useful when copying some portion of the transaction for use elsewhere (for instance,
"--no-send-hints --hide-receive --hide-informational" is a useful way to get only the
client-side commands for a given transaction and "--no-info-hints --tls-get-peer-cert"
for copying the peer certificate). "--no-hints" is identical to specifying
"--no-info-hints --no-send-hints --no-receive-hints". (Arg-None)
-raw, --show-raw-text
This option will print a hex dump of raw data sent and received by Swaks. Each hex
dump is the contents of a single read or write on the network. This should be
identical to what is already being displayed (with the exception of the "\r"
characters being removed). This option is useful in seeing details when servers are
sending lots of data in single packets, or breaking up individual lines into multiple
packets. If you really need to go in depth in that area you're probably better with a
packet sniffer, but this option is a good first step to seeing odd connection issues.
(Arg-None)
--output, --output-file <file-path>
--output-file-stdout <file-path>
--output-file-stderr <file-path>
These options allow the user to send output to files instead of "STDOUT"/"STDERR".
The first option sends both to the same file. The arguments of &STDOUT and &STDERR
are treated specially, referring to the "normal" file handles, so
"--output-file-stderr '&STDOUT'" would redirect "STDERR" to "STDOUT". These options
are honored for all output except "--help" and "--version". (Arg-Required)
-pp, --protect-prompt
Don't echo user input on prompts that are potentially sensitive (right now only
authentication password). Very specifically, any option which is marked 'Sensitive'
and eventually prompts for an argument will do its best to mask that argument from
being echoed. See also "--auth-hide-password". (Arg-None)
-hr, --hide-receive
Don't display lines sent from the remote server being received by Swaks. (Arg-None)
-hs, --hide-send
Don't display lines being sent by Swaks to the remote server. (Arg-None)
-hi, --hide-informational
Don't display non-error informational lines from Swaks itself. (Arg-None)
-ha, --hide-all
Do not display any content to the terminal. (Arg-None)
-S, --silent [ 1 | 2 | 3 ]
Cause Swaks to be silent. If no argument is given or if an argument of "1" is given,
print no output unless/until an error occurs, after which all output is shown. If an
argument of "2" is given, only print errors. If "3" is given, show no output ever.
"--silent" affects most output but not all. For instance, "--help", "--version",
"--dump", and "--dump-mail" are not affected. For historical reasons, -S is not
settable via environment variable on Windows, use SWAKS_OPT_silent instead. (Arg-
Optional)
--support
Print capabilities and exit. Certain features require non-standard Perl modules.
This option evaluates whether these modules are present and displays which
functionality is available and which isn't, and which modules would need to be added
to gain the missing functionality. (Arg-None)
--dump-mail
Cause Swaks to process all options to generate the message it would send, then print
that message to "STDOUT" instead of sending it. This output is identical to the
"data" section of "--dump", except without the trailing dot. (Arg-None)
--dump [<section>[,<section>[,...]]]
This option causes Swaks to print the results of option processing, immediately before
mail would have been sent. No mail will be sent when "--dump" is used. Note that
"--dump" is a pure self-diagnosis tool and no effort is made or will ever be made to
mask passwords in the "--dump" output. If a section is provided as an argument to this
option, only the requested section will be shown. Currently supported arguments are
SUPPORT, APP, OUTPUT, TRANSPORT, PROTOCOL, XCLIENT, PROXY, TLS, AUTH, DATA, and ALL.
If no argument is provided, all sections are displayed (Arg-Optional)
--help
Display this help information and exit. (Arg-None)
--version
Display version information and exit. (Arg-None)
DEPRECATIONS
The following features are deprecated and will be removed in a future version of Swaks
use of IO::Socket and IO::Socket::INET6 modules
Will be removed no sooner than (February 1, 2025).
The primary method of sending over IPv4 and IPv6 sockets is implemented with the
IO::Socket::IP module. For the time being there is still legacy support of the
IO::Socket and IO::Socket::INET6 modules which were previously used. Please ensure
IO::Socket::IP is installed to ensure future functionality.
PORTABILITY
OPERATING SYSTEMS
This program was primarily intended for use on UNIX-like operating systems, and it
should work on any reasonable version thereof. It has been developed and tested on
Solaris, Linux, and Mac OS X and is feature complete on all of these.
This program is known to demonstrate basic functionality on Windows using Strawberry
Perl. In all documentation, unless otherwise noted, "Windows" refers to running Swaks
via CMD.exe, not WSL or cygwin. It has not been fully tested, but known to work are
basic SMTP functionality and the LOGIN, PLAIN, and CRAM-MD5 auth types. Unknown is
any TLS functionality and the NTLM/SPA and DIGEST-MD5 auth types. Some functionality
is known to be limited on Windows, including inability to embed header name in
environment variables (see "CONFIGURATION ENVIRONMENT VARIABLES" and "--header"),
inability to generate a local-timezone date string (see "%DATE%" token under
"--data"), inability to use "-S" option as an environment variable (see "--silent"),
and inability to have a "set but empty" value in an environment variable (see
"CONFIGURATION ENVIRONMENT VARIABLES" for workaround).
Because this program should work anywhere Perl works, I would appreciate knowing about
any new operating systems you've thoroughly used Swaks on as well as any problems
encountered on a new OS.
MAIL SERVERS
This program was almost exclusively developed against Exim mail servers. It has been
used casually by the author, though not thoroughly tested, with Sendmail, Smail,
Exchange, Oracle Collaboration Suite, qpsmtpd, and Communigate. Because all
functionality in Swaks is based on known standards it should work with any fairly
modern mail server. If a problem is found, please alert the author at the address
below.
ENVIRONMENT VARIABLES
LOGNAME
If Swaks must create a sender address, $LOGNAME is used as the message local-part if
it is set, and unless "--force-getpwuid" is used.
SWAKS_HOME
Used when searching for a .swaksrc configuration file. See OPTION PROCESSING ->
"CONFIGURATION FILES" above.
SWAKS_OPT_*
Environment variable prefix used to specify Swaks options from environment variables.
See OPTION PROCESSING -> "CONFIGURATION ENVIRONMENT VARIABLES" above.
EXIT CODES
0 no errors occurred
1 error parsing command line options
2 error connecting to remote server
3 unknown connection type
4 while running with connection type of "pipe", fatal problem writing to or reading from
the child process
5 while running with connection type of "pipe", child process died unexpectedly. This
can mean that the program specified with "--pipe" doesn't exist.
6 Connection closed unexpectedly. If the close is detected in response to the 'QUIT'
Swaks sends following an unexpected response, the error code for that unexpected
response is used instead. For instance, if a mail server returns a 550 response to a
MAIL FROM: and then immediately closes the connection, Swaks detects that the
connection is closed, but uses the more specific exit code 23 to detail the nature of
the failure. If instead the server return a 250 code and then immediately closes the
connection, Swaks will use the exit code 6 because there is not a more specific exit
code.
10 error in prerequisites (needed module not available)
21 error reading initial banner from server
22 error in HELO transaction
23 error in MAIL transaction
24 no RCPTs accepted
25 server returned error to DATA request
26 server did not accept mail following data
27 server returned error after normal-session quit request
28 error in AUTH transaction
29 error in TLS transaction
30 PRDR requested/required but not advertised
32 error in EHLO following TLS negotiation
33 error in XCLIENT transaction
34 error in EHLO following XCLIENT
35 error in PROXY option processing
36 error sending PROXY banner
ABOUT THE NAME
The name "Swaks" is a (sort-of) acronym for "SWiss Army Knife SMTP". It was chosen to be
fairly distinct and pronounceable. While "Swaks" is unique as the name of a software
package, it has some other, non-software meanings. Please send in other uses of "swak" or
"swaks" for inclusion.
"Sealed With A Kiss"
SWAK/SWAKs turns up occasionally on the internet with the meaning "with love".
bad / poor / ill (Afrikaans)
Seen in the headline "SA se bes en swaks gekledes in 2011", which was translated as
"best and worst dressed" by native speakers. Google Translate doesn't like "swaks
gekledes", but it will translate "swak" as "poor" and "swak geklede" as "ill-dressed".
LICENSE
This program is free software; you can redistribute it and/or modify it under the terms of
the GNU General Public License as published by the Free Software Foundation; either
version 2 of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with this program;
if not, write to the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston,
MA 02110-1301, USA.
CONTACT INFORMATION
General contact, questions, patches, requests, etc to proj-swaks@jetmore.net.
Change logs, this help, and the latest version are found at
<http://www.jetmore.org/john/code/swaks/>.
Swaks is crafted with love by John Jetmore from the cornfields of Indiana, United States
of America.
NOTIFICATIONS
Email
updates-swaks@jetmore.net
If you would like to be put on a list to receive notifications when a new version of
Swaks is released, please send an email to this address. There will not be a response
to your email.
Website
<http://www.jetmore.org/john/blog/c/swaks/>
RSS Feed
<http://www.jetmore.org/john/blog/c/swaks/feed/>
Twitter
<http://twitter.com/SwaksSMTP>