Provided by: gnutls-bin_3.8.1-4ubuntu1.3_amd64 
NAME
gnutls-serv - GnuTLS server
SYNOPSIS
gnutls-serv [-flags] [-flag [value]] [--option-name[[=| ]value]]
All arguments must be options.
DESCRIPTION
Server program that listens to incoming TLS connections.
OPTIONS
-d num, --debug=num
Enable debugging. This option takes an integer number as its argument. The value
of num is constrained to being:
in the range 0 through 9999
Specifies the debug level.
--sni-hostname=str
Server's hostname for server name extension.
Server name of type host_name that the server will recognise as its own. If the
server receives client hello with different name, it will send a warning-level
unrecognized_name alert.
--sni-hostname-fatal
Send fatal alert on sni-hostname mismatch.
--alpn=str
Specify ALPN protocol to be enabled by the server. This option may appear an
unlimited number of times.
Specify the (textual) ALPN protocol for the server to use.
--alpn-fatal
Send fatal alert on non-matching ALPN name.
--noticket
Don't accept session tickets.
--earlydata
Accept early data.
--maxearlydata=num
The maximum early data size to accept. This option takes an integer number as its
argument. The value of num is constrained to being:
in the range 1 through 2147483648
--nocookie
Don't require cookie on DTLS sessions.
-g, --generate
Generate Diffie-Hellman parameters.
-q, --quiet
Suppress some messages.
--nodb Do not use a resumption database.
--http Act as an HTTP server.
--echo Act as an Echo server.
--crlf Do not replace CRLF by LF in Echo server mode.
-u, --udp
Use DTLS (datagram TLS) over UDP.
--mtu=num
Set MTU for datagram TLS. This option takes an integer number as its argument.
The value of num is constrained to being:
in the range 0 through 17000
--srtp-profiles=str
Offer SRTP profiles.
-a, --disable-client-cert
Do not request a client certificate. This option must not appear in combination
with any of the following options: require-client-cert.
-r, --require-client-cert
Require a client certificate.
This option before 3.6.0 used to imply --verify-client-cert. Since 3.6.0 it will
no longer verify the certificate by default.
--verify-client-cert
If a client certificate is sent then verify it.
Do not require, but if a client certificate is sent then verify it and close the
connection if invalid.
--compress-cert=str
Compress certificate. This option may appear an unlimited number of times.
This option sets a supported compression method for certificate compression.
-b, --heartbeat
Activate heartbeat support.
Regularly ping client via heartbeat extension messages
--x509fmtder
Use DER format for certificates to read from.
--priority=str
Priorities string.
TLS algorithms and protocols to enable. You can use predefined sets of ciphersuites
such as PERFORMANCE, NORMAL, SECURE128, SECURE256. The default is NORMAL.
Check the GnuTLS manual on section “Priority strings” for more information on
allowed keywords
--dhparams=file
DH params file to use.
--x509cafile=str
Certificate file or PKCS #11 URL to use.
--x509crlfile=file
CRL file to use.
--pgpkeyfile=file
PGP Key file to use.
NOTE: THIS OPTION IS DEPRECATED
--x509keyfile=str
X.509 key file or PKCS #11 URL to use. This option may appear an unlimited number
of times.
Specify the private key file or URI to use; it must correspond to the certificate
specified in --x509certfile. Multiple keys and certificates can be specified with
this option and in that case each occurrence of keyfile must be followed by the
corresponding x509certfile or vice-versa.
--x509certfile=str
X.509 Certificate file or PKCS #11 URL to use. This option may appear an unlimited
number of times.
Specify the certificate file or URI to use; it must correspond to the key specified
in --x509keyfile. Multiple keys and certificates can be specified with this option
and in that case each occurrence of keyfile must be followed by the corresponding
x509certfile or vice-versa.
--x509dsakeyfile
This is an alias for the --x509keyfile option.
NOTE: THIS OPTION IS DEPRECATED
--x509dsacertfile
This is an alias for the --x509certfile option.
NOTE: THIS OPTION IS DEPRECATED
--x509ecckeyfile
This is an alias for the --x509keyfile option.
NOTE: THIS OPTION IS DEPRECATED
--x509ecccertfile
This is an alias for the --x509certfile option.
NOTE: THIS OPTION IS DEPRECATED
--rawpkkeyfile=str
Private key file (PKCS #8 or PKCS #12) or PKCS #11 URL to use. This option may
appear an unlimited number of times.
Specify the private key file or URI to use; it must correspond to the raw
public-key specified in --rawpkfile. Multiple key pairs can be specified with this
option and in that case each occurrence of keyfile must be followed by the
corresponding rawpkfile or vice-versa.
In order to instruct the application to negotiate raw public keys one must enable
the respective certificate types via the priority strings (i.e. CTYPE-CLI-* and
CTYPE-SRV-* flags).
Check the GnuTLS manual on section “Priority strings” for more information on
how to set certificate types.
--rawpkfile=str
Raw public-key file to use. This option may appear an unlimited number of times.
This option must appear in combination with the following options: rawpkkeyfile.
Specify the raw public-key file to use; it must correspond to the private key
specified in --rawpkkeyfile. Multiple key pairs can be specified with this option
and in that case each occurrence of keyfile must be followed by the corresponding
rawpkfile or vice-versa.
In order to instruct the application to negotiate raw public keys one must enable
the respective certificate types via the priority strings (i.e. CTYPE-CLI-* and
CTYPE-SRV-* flags).
Check the GnuTLS manual on section “Priority strings” for more information on
how to set certificate types.
--srppasswd=file
SRP password file to use.
--srppasswdconf=file
SRP password configuration file to use.
--pskpasswd=file
PSK password file to use.
--pskhint=str
PSK identity hint to use.
--ocsp-response=str
The OCSP response to send to client. This option may appear an unlimited number of
times.
If the client requested an OCSP response, return data from this file to the client.
--ignore-ocsp-response-errors
Ignore any errors when setting the OCSP response.
That option instructs gnutls to not attempt to match the provided OCSP responses
with the certificates.
-p num, --port=num
The port to connect to. This option takes an integer number as its argument.
-l, --list
Print a list of the supported algorithms and modes.
Print a list of the supported algorithms and modes. If a priority string is given
then only the enabled ciphersuites are shown.
--provider=file
Specify the PKCS #11 provider library.
This will override the default options in /etc/gnutls/pkcs11.conf
--keymatexport=str
Label used for exporting keying material.
--keymatexportsize=num
Size of the exported keying material. This option takes an integer number as its
argument.
--recordsize=num
The maximum record size to advertise. This option takes an integer number as its
argument. The value of num is constrained to being:
in the range 0 through 16384
--httpdata=file
The data used as HTTP response.
--timeout=num
The timeout period for server. This option takes an integer number as its
argument.
--attime=timestamp
Perform validation at the timestamp instead of the system time.
timestamp is an instance in time encoded as Unix time or in a human
readable timestring such as "29 Feb 2004", "2004-02-29". Full documentation
available at
<https://www.gnu.org/software/coreutils/manual/html_node/Date-input-formats.html>
or locally via info '(coreutils) date invocation'.
-v arg, --version=arg
Output version of program and exit. The default mode is `v', a simple version.
The `c' mode will print copyright information and `n' will print the full copyright
notice.
-h, --help
Display usage information and exit.
-!, --more-help
Pass the extended usage information through a pager.
EXAMPLES
Running your own TLS server based on GnuTLS can be useful when debugging clients and/or
GnuTLS itself. This section describes how to use gnutls-serv as a simple HTTPS server.
The most basic server can be started as:
gnutls-serv --http --priority "NORMAL:+ANON-ECDH:+ANON-DH"
It will only support anonymous ciphersuites, which many TLS clients refuse to use.
The next step is to add support for X.509. First we generate a CA:
$ certtool --generate-privkey > x509-ca-key.pem
$ echo 'cn = GnuTLS test CA' > ca.tmpl
$ echo 'ca' >> ca.tmpl
$ echo 'cert_signing_key' >> ca.tmpl
$ certtool --generate-self-signed --load-privkey x509-ca-key.pem --template ca.tmpl --outfile x509-ca.pem
Then generate a server certificate. Remember to change the dns_name value to the name of
your server host, or skip that command to avoid the field.
$ certtool --generate-privkey > x509-server-key.pem
$ echo 'organization = GnuTLS test server' > server.tmpl
$ echo 'cn = test.gnutls.org' >> server.tmpl
$ echo 'tls_www_server' >> server.tmpl
$ echo 'encryption_key' >> server.tmpl
$ echo 'signing_key' >> server.tmpl
$ echo 'dns_name = test.gnutls.org' >> server.tmpl
$ certtool --generate-certificate --load-privkey x509-server-key.pem --load-ca-certificate x509-ca.pem --load-ca-privkey x509-ca-key.pem --template server.tmpl --outfile x509-server.pem
For use in the client, you may want to generate a client certificate as well.
$ certtool --generate-privkey > x509-client-key.pem
$ echo 'cn = GnuTLS test client' > client.tmpl
$ echo 'tls_www_client' >> client.tmpl
$ echo 'encryption_key' >> client.tmpl
$ echo 'signing_key' >> client.tmpl
$ certtool --generate-certificate --load-privkey x509-client-key.pem --load-ca-certificate x509-ca.pem --load-ca-privkey x509-ca-key.pem --template client.tmpl --outfile x509-client.pem
To be able to import the client key/certificate into some applications, you will need to
convert them into a PKCS#12 structure. This also encrypts the security sensitive key with
a password.
$ certtool --to-p12 --load-ca-certificate x509-ca.pem --load-privkey x509-client-key.pem --load-certificate x509-client.pem --outder --outfile x509-client.p12
For icing, we'll create a proxy certificate for the client too.
$ certtool --generate-privkey > x509-proxy-key.pem
$ echo 'cn = GnuTLS test client proxy' > proxy.tmpl
$ certtool --generate-proxy --load-privkey x509-proxy-key.pem --load-ca-certificate x509-client.pem --load-ca-privkey x509-client-key.pem --load-certificate x509-client.pem --template proxy.tmpl --outfile x509-proxy.pem
Then start the server again:
$ gnutls-serv --http --x509cafile x509-ca.pem --x509keyfile x509-server-key.pem --x509certfile x509-server.pem
Try connecting to the server using your web browser. Note that the server listens to port
5556 by default.
While you are at it, to allow connections using ECDSA, you can also create a ECDSA key and
certificate for the server. These credentials will be used in the final example below.
$ certtool --generate-privkey --ecdsa > x509-server-key-ecc.pem
$ certtool --generate-certificate --load-privkey x509-server-key-ecc.pem --load-ca-certificate x509-ca.pem --load-ca-privkey x509-ca-key.pem --template server.tmpl --outfile x509-server-ecc.pem
The next step is to add support for SRP authentication. This requires an SRP password file
created with srptool. To start the server with SRP support:
gnutls-serv --http --priority NORMAL:+SRP-RSA:+SRP --srppasswdconf srp-tpasswd.conf --srppasswd srp-passwd.txt
Let's also start a server with support for PSK. This would require a password file created
with psktool.
gnutls-serv --http --priority NORMAL:+ECDHE-PSK:+PSK --pskpasswd psk-passwd.txt
If you want a server with support for raw public-keys we can also add these credentials.
Note however that there is no identity information linked to these keys as is the case
with regular x509 certificates. Authentication must be done via different means. Also we
need to explicitly enable raw public-key certificates via the priority strings.
gnutls-serv --http --priority NORMAL:+CTYPE-CLI-RAWPK:+CTYPE-SRV-RAWPK --rawpkfile srv.rawpk.pem --rawpkkeyfile srv.key.pem
Finally, we start the server with all the earlier parameters and you get this command:
gnutls-serv --http --priority NORMAL:+PSK:+SRP:+CTYPE-CLI-RAWPK:+CTYPE-SRV-RAWPK --x509cafile x509-ca.pem --x509keyfile x509-server-key.pem --x509certfile x509-server.pem --x509keyfile x509-server-key-ecc.pem --x509certfile x509-server-ecc.pem --srppasswdconf srp-tpasswd.conf --srppasswd srp-passwd.txt --pskpasswd psk-passwd.txt --rawpkfile srv.rawpk.pem --rawpkkeyfile srv.key.pem
EXIT STATUS
One of the following exit values will be returned:
0 (EXIT_SUCCESS)
Successful program execution.
1 (EXIT_FAILURE)
The operation failed or the command syntax was not valid.
SEE ALSO
gnutls-cli-debug(1), gnutls-cli(1)
AUTHORS
COPYRIGHT
Copyright (C) 2020-2023 Free Software Foundation, and others all rights reserved. This
program is released under the terms of the GNU General Public License, version 3 or later
BUGS
Please send bug reports to: bugs@gnutls.org