Provided by: oidentd_2.5.0-1_amd64 
NAME
oidentd.conf - oidentd configuration files
DESCRIPTION
The oidentd configuration files are used to control the responses oidentd sends to clients
after receiving a query for a connection owned by a particular user.
The system-wide configuration file /usr/local/etc/oidentd.conf specifies the types of
responses individual users are permitted to send. By default, users must respond with
their real username.
The user configuration files ~/.config/oidentd.conf allow users to send custom ident
responses or to hide their identities, provided that they have been granted the necessary
capabilities through the system-wide configuration file. If this file does not exist or
oidentd was compiled without XDG Base Directory support, the file ~/.oidentd.conf is used
instead. Note that user configuration files are read only after a connection is determined
to belong to the user in question.
SYSTEM-WIDE CONFIGURATION FILE
The system-wide configuration file is used to grant capabilities to users or force users
to use a certain capability. The default behavior is not to grant any privileges, which
means that all users must send their real usernames in response to ident queries. The
system-wide configuration file may be empty or missing, in which case this default
applies. Changes to this file take effect only after oidentd is reloaded (which occurs
when a SIGHUP signal is received) or restarted.
The system-wide configuration file contains zero or one directive of the following form:
default {
range-directives...
}
This default directive matches all users for which no explicit rules have been defined.
Any user directives following this directive inherit the capabilities it defines. If
present, the default directive should be the first directive in the user configuration
file.
The system-wide configuration file may also contain zero or more directives of the
following form:
user username {
range-directives...
}
This user directive applies only to the specified user.
USER CONFIGURATION FILE
Each user may create a user configuration file at ~/.config/oidentd.conf or
~/.oidentd.conf. This file must be readable by the user oidentd runs as. The user
configuration file is read automatically after every successful lookup, so any changes
take effect immediately.
The user configuration file contains zero or one directive of the following form:
global {
capability-statements...
}
This global directive matches all connections owned by the user. If present, it should be
the first directive in the user configuration file.
The user configuration file may also contain zero or more directives of the following
form:
range-specification {
capability-statements...
}
This range directive applies only to connections that match the given range specification.
RANGE DIRECTIVES
At most one range directive in any given scope may take the following form:
default {
capability-directives...
}
This default directive defines rules for all connections that do not match any other range
directive. If present, the default directive should be the first directive in its scope.
A range directive may also take the following form:
range-specification {
capability-directives...
}
This range directive applies only to connections that match the given range specification.
RANGE SPECIFICATIONS
A range specification consists of filters that define which connections a range directive
applies to. It takes the following form:
to fhost fport fport from lhost lport lport
This range specification matches only connections with the specified foreign host, foreign
port, local host, and local port. At least one of these filters must be specified. Omitted
filters match any value. Filters may be specified in any order.
The fhost filter specifies the foreign host or address of a connection, from the
perspective of the machine running oidentd.
The fport filter specifies the foreign port or port range of a connection.
The lhost filter specifies the local host or address of a connection, from the perspective
of the machine running oidentd. This may be useful for supporting virtual hosts on systems
with more than one IP address.
The lport filter specifies the local port or port range of a connection.
Ports can be specified either numerically (e.g., 113) or using a service name (e.g.,
ident). Port ranges are specified numerically as min:max. The min port may be omitted to
select all ports less than or equal to the max port. Likewise, the max port may be omitted
to select all ports greater than or equal to the min port.
CAPABILITY DIRECTIVES
A capability directive may take one of the following forms:
allow capability
In this form, the directive grants the user permission to use the specified capability.
deny capability
In this form, the directive revokes the user’s permission to use the specified capability.
force capability-statement
In this form, the directive forces the user to use the specified capability.
CAPABILITIES
The following expressions are valid capabilities:
forward
hide
numeric
random
random_numeric
These capabilities allow users to use the corresponding capability statements.
spoof
The spoof capability allows users to send custom ident replies. Note that this does not
include replying with the name of another user or spoofing replies for connections to
privileged foreign ports.
spoof_all
The spoof_all capability allows users to reply with the names of other users. This
capability should be used with care, as it allows users to impersonate other users on the
local system. The spoof_all capability only works in conjunction with spoof, but does not
imply it.
spoof_privport
The spoof_privport capability allows users to spoof replies for connections to privileged
foreign ports (with port numbers below 1024). The spoof_privport capability only works in
conjunction with spoof, but does not imply it.
CAPABILITY STATEMENTS
A capability statement may take one of the following forms:
forward host port
Forward received queries to another ident server. The target server must support
forwarding (like oidentd with the --proxy option).
Additional capabilities may be required for forwarding to succeed. For example, the spoof
capability is required if the target server sends a response other than the user’s name on
the forwarding server. It may therefore be desirable to also grant at least one of hide,
spoof, spoof_all, and spoof_privport in addition to the forward capability. If force
forward is used, no additional checks are performed and no capabilities are required.
If forwarding fails, oidentd responds with a "HIDDEN-USER" error or with the user’s real
username, depending on whether the user has been granted the hide capability. Replies are
logged, allowing the system administrator to identify which user sent a particular reply.
hide
Hide ident replies from clients. When this capability is used, oidentd reports a
"HIDDEN-USER" error to ident clients instead of sending an ident reply.
numeric
Respond with the user ID (UID).
random
Send randomly generated, alphanumeric ident replies. A new reply is generated for each
ident lookup. Replies are logged, allowing the system administrator to identify which user
sent a particular reply.
random_numeric
Send randomly generated, numeric ident replies between 0 (inclusive) and 100,000
(exclusive), prefixed with "user". A new reply is generated for each ident lookup. Replies
are logged, allowing the system administrator to identify which user sent a particular
reply.
reply reply1 [reply2 ...]
Send an ident reply chosen at random from the given list of quoted replies. When used in a
user configuration file, at most 20 replies may be specified. In the system-wide
configuration file, up to 255 replies may be specified. Replies are logged, allowing the
system administrator to identify which user sent a particular reply.
EXAMPLES
SYSTEM-WIDE CONFIGURATION FILE
default {
default {
allow spoof
}
fport 6667 {
deny spoof
allow hide
}
}
Allow all users to spoof ident replies, except on connections to port 6667. Only on
connections to port 6667, allow users to hide their ident replies.
user "root" {
default {
force hide
}
}
Hide all connections owned by the root user.
user "lisa" {
lport 1024: {
force reply "me"
}
}
For connections owned by user "lisa" on local port 1024 or greater, always reply with
"me", ignoring any settings in the user configuration file.
USER CONFIGURATION FILE
global {
reply "paul"
}
Reply with "paul" to all ident queries.
to irc.example.net fport 6667 {
hide
}
Hide ident replies for connections to irc.example.net on port 6667.
STRING FORMATTING
Strings may be enclosed in double quotes. This is useful for strings containing special
characters that would otherwise be interpreted in an unintended way.
Quoted strings may contain the following escape sequences:
\a alert (bell)
\b backspace
\f form feed
\n newline (line feed)
\r carriage return
\t horizontal tab
\v vertical tab
\\ backslash
\" double quotation mark
\NNN the character with octal numerical value NNN
\xNN the character with hexadecimal numerical value NN
COMMENTS
After encountering a number sign ("#"), oidentd ignores any remaining text on the same
line. This allows users to add comments to the configuration file. Comments can also be
written in the following form, which allows them to span multiple lines:
/* comment */
AUTHOR
Janik Rabe <oidentd@janikrabe.com>
https://oidentd.janikrabe.com
Originally written by Ryan McCabe.
BUGS
Please report any bugs to Janik Rabe <oidentd@janikrabe.com>.
SEE ALSO
oidentd(8) oidentd_masq.conf(5)