gnutls-serv(1)                  User Commands                 gnutls-serv(1)

NAME         top

       gnutls-serv - GnuTLS server

SYNOPSIS         top

       gnutls-serv [-flags] [-flag [value]] [--option-name[[=| ]value]]

       All arguments must be options.

DESCRIPTION         top

       Server program that listens to incoming TLS connections.

OPTIONS         top

       -d number, --debug=number
              Enable debugging.  This option takes an integer number as its
              argument.  The value of number is constrained to being:
                  in the range  0 through 9999

              Specifies the debug level.

              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.

              Send fatal alert on sni-hostname mismatch.

              Don't accept session tickets.

       -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.

       -u, --udp
              Use DTLS (datagram TLS) over UDP.

              Set MTU for datagram TLS.  This option takes an integer number
              as its argument.  The value of number is constrained to being:
                  in the range  0 through 17000

              Offer SRTP profiles.

       -a, --disable-client-cert
              Do not request a client certificate.

       -r, --require-client-cert
              Require a client certificate.

              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.

       -b, --heartbeat
              Activate heartbeat support.

              Regularly ping client via heartbeat extension messages

              Use DER format for certificates to read from.

              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

              DH params file to use.

              Certificate file or PKCS #11 URL to use.

              CRL file to use.

              PGP Key file to use.

              PGP Key ring file to use.

              PGP Public Key (certificate) file to use.

              X.509 key file or PKCS #11 URL to use.

              X.509 Certificate file or PKCS #11 URL to use.

              Alternative X.509 key file or PKCS #11 URL to use.

              Alternative X.509 Certificate file or PKCS #11 URL to use.

              Alternative X.509 key file or PKCS #11 URL to use.

              Alternative X.509 Certificate file or PKCS #11 URL to use.

              PGP subkey to use (hex or auto).

              SRP password file to use.

              SRP password configuration file to use.

              PSK password file to use.

              PSK identity hint to use.

              The OCSP response to send to client.

              If the client requested an OCSP response, return data from
              this file to the client.

       -p number, --port=number
              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.

              Specify the PKCS #11 provider library.

              This will override the default options in

       -h, --help
              Display usage information and exit.

       -!, --more-help
              Pass the extended usage information through a pager.

       -v [{v|c|n --version [{v|c|n}]}]
              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.

EXAMPLES         top

       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 =' >> server.tmpl
           $ echo 'tls_www_server' >> server.tmpl
           $ echo 'encryption_key' >> server.tmpl
           $ echo 'signing_key' >> server.tmpl
           $ echo 'dns_name =' >> 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 DSA, you can also
       create a DSA key and certificate for the server.  These credentials
       will be used in the final example below.

           $ certtool --generate-privkey --dsa > x509-server-key-dsa.pem
           $ certtool --generate-certificate --load-privkey x509-server-key-dsa.pem   --load-ca-certificate x509-ca.pem --load-ca-privkey x509-ca-key.pem   --template server.tmpl --outfile x509-server-dsa.pem

       The next step is to create OpenPGP credentials for the server.

           gpg --gen-key
           Enter whatever details you want, use '' as name...

       Make a note of the OpenPGP key identifier of the newly generated key,
       here it was 5D1D14D8.  You will need to export the key for GnuTLS to
       be able to use it.

           gpg -a --export 5D1D14D8 > openpgp-server.txt
           gpg --export 5D1D14D8 > openpgp-server.bin
           gpg --export-secret-keys 5D1D14D8 > openpgp-server-key.bin
           gpg -a --export-secret-keys 5D1D14D8 > openpgp-server-key.txt

       Let's start the server with support for OpenPGP credentials:

           gnutls-serv --http --priority NORMAL:+CTYPE-OPENPGP             --pgpkeyfile openpgp-server-key.txt             --pgpcertfile openpgp-server.txt

       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

       Finally, we start the server with all the earlier parameters and you
       get this command:

           gnutls-serv --http --priority NORMAL:+PSK:+SRP:+CTYPE-OPENPGP             --x509cafile x509-ca.pem             --x509keyfile x509-server-key.pem             --x509certfile x509-server.pem             --x509dsakeyfile x509-server-key-dsa.pem             --x509dsacertfile x509-server-dsa.pem             --pgpkeyfile openpgp-server-key.txt             --pgpcertfile openpgp-server.txt             --srppasswdconf srp-tpasswd.conf             --srppasswd srp-passwd.txt             --pskpasswd psk-passwd.txt

EXIT STATUS         top

       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.

       70  (EX_SOFTWARE)
              libopts had an internal operational error.  Please report it
              to  Thank you.

SEE ALSO         top

       gnutls-cli-debug(1), gnutls-cli(1)

AUTHORS         top

       Nikos Mavrogiannopoulos, Simon Josefsson and others; see
       /usr/share/doc/gnutls/AUTHORS for a complete list.

COPYRIGHT         top

       Copyright (C) 2000-2017 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         top

       Please send bug reports to:

NOTES         top

       This manual page was AutoGen-erated from the gnutls-serv option

COLOPHON         top

       This page is part of the GnuTLS (GnuTLS Transport Layer Security
       Library) project.  Information about the project can be found at 
       ⟨⟩.  If you have a bug report for this manual
       page, send it to  This page was obtained from the
       tarball gnutls-3.5.9.tar.xz fetched from 
       ⟨⟩ on 2017-07-05.  If you discover
       any rendering problems in this HTML version of the page, or you
       believe there is a better or more up-to-date source for the page, or
       you have corrections or improvements to the information in this
       COLOPHON (which is not part of the original manual page), send a mail

3.5.9                            12 Feb 2017                  gnutls-serv(1)