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Updated: Thursday, June 13, 2019
 
 

postfix-tls (1)

Name

postfix-tls - Postfix TLS management

Synopsis

postfix tls subcommand

Description

POSTFIX-TLS(1)              General Commands Manual             POSTFIX-TLS(1)



NAME
       postfix-tls - Postfix TLS management

SYNOPSIS
       postfix tls subcommand

DESCRIPTION
       The  "postfix  tls subcommand" feature enables opportunistic TLS in the
       Postfix SMTP client or server, and manages Postfix SMTP server  private
       keys and certificates.

       The following subcommands are available:

       enable-client [-r randsource]
              Enable opportunistic TLS in the Postfix SMTP client, if all SMTP
              client TLS settings are at  their  default  values.   Otherwise,
              suggest parameter settings without making any changes.

              Specify  randsource to update the value of the tls_random_source
              configuration parameter (typically, /dev/urandom).  Prepend dev:
              to device paths or egd: to EGD socket paths.

              See also the all-default-client subcommand.

       enable-server [-r randsource] [-a algorithm] [-b bits] [hostname...]
              Create  a new private key and self-signed server certificate and
              enable opportunistic TLS in the Postfix SMTP server, if all SMTP
              server  TLS  settings  are  at their default values.  Otherwise,
              suggest parameter settings without making any changes.

              The randsource parameter is as with enable-client above, and the
              remaining options are as with new-server-key below.

              See also the all-default-server subcommand.

       new-server-key [-a algorithm] [-b bits] [hostname...]
              Create a new private key and self-signed server certificate, but
              do not deploy them. Log and display commands to deploy  the  new
              key  and  corresponding  certificate.  Also log and display com-
              mands to output a corresponding CSR or TLSA records which may be
              needed  to  obtain  a CA certificate or to update DNS before the
              new key can be deployed.

              The algorithm defaults to rsa, and bits defaults  to  2048.   If
              you  choose  the  ecdsa  algorithm then bits will be an EC curve
              name (by default secp256r1, also known as  prime256v1).   Curves
              other  than secp256r1, secp384r1 or secp521r1 are unlikely to be
              widely interoperable.  When generating EC keys, use one of these
              three.  DSA keys are obsolete and are not supported.

              Note:  ECDSA support requires OpenSSL 1.0.0 or later and may not
              be available on your system.  Not all client systems  will  sup-
              port  ECDSA,  so  you'll  generally  want to deploy both RSA and
              ECDSA certificates to make use of ECDSA with compatible  clients
              and  RSA with the rest. If you want to deploy certificate chains
              with intermediate CAs for both RSA and  ECDSA,  you'll  want  at
              least OpenSSL 1.0.2, as earlier versions may not handle multiple
              chain files correctly.

              The first hostname argument will be the CommonName of  both  the
              subject  and issuer of the self-signed certificate.  It, and any
              additional hostname arguments, will also be listed as DNS alter-
              native names in the certificate.  If no hostname is provided the
              value of the myhostname main.cf parameter will be used.

              For RSA, the generated private key  and  certificate  files  are
              named   key-yyyymmdd-hhmmss.pem   and  cert-yyyymmdd-hhmmss.pem,
              where yyyymmdd is the calendar date and hhmmss is  the  time  of
              day  in  UTC.   For  ECDSA, the file names start with eckey- and
              eccert- instead of key- and cert- respectively.

              Before deploying the new key and certificate with  DANE,  update
              the  DNS  with  new  DANE  TLSA records, then wait for secondary
              nameservers to update and then for stale records in  remote  DNS
              caches to expire.

              Before  deploying  a new CA certificate make sure to include all
              the required intermediate issuing CA certificates  in  the  cer-
              tificate  chain  file.  The server certificate must be the first
              certificate in the chain file.  Overwrite and  deploy  the  file
              with  the  original  self-signed  certificate that was generated
              together with the key.

       new-server-cert [-a algorithm] [-b bits] [hostname...]
              This is just like new-server-key except that, rather than gener-
              ating  a  new private key, any currently deployed private key is
              copied to the new key file.  Thus if you're publishing DANE TLSA
              "3  1  1"  or  "3  1  2" records, there is no need to update DNS
              records.  The algorithm and bits arguments are used only  if  no
              key of the same algorithm is already configured.

              This  command is rarely needed, because the self-signed certifi-
              cates generated have a 100-year nominal  expiration  time.   The
              underlying  public key algorithms may well be obsoleted by quan-
              tum computers long before then.

              The most plausible reason for using this  command  is  when  the
              system hostname changes, and you'd like the name in the certifi-
              cate to match the new hostname (not required for DANE "3  1  1",
              but some needlessly picky non-DANE opportunistic TLS clients may
              log warnings or even refuse to communicate).

       deploy-server-cert certfile keyfile
              This subcommand deploys the certificates in certfile and private
              key  in  keyfile  (which are typically generated by the commands
              above, which will also log and display the full  command  needed
              to  deploy  the  generated  key and certificate).  After the new
              certificate and key are deployed any obsolete keys and  certifi-
              cates  may  be removed by hand.   The keyfile and certfile file-
              names may be relative to the Postfix configuration directory.

       output-server-csr [-k keyfile] [hostname...]
              Write to stdout a certificate  signing  request  (CSR)  for  the
              specified keyfile.

              Instead  of an absolute pathname or a pathname relative to $con-
              fig_directory, keyfile may specify  one  of  the  supported  key
              algorithm  names  (see  "postconf -T public-key-algorithms"). In
              that case, the corresponding setting from  main.cf  is  used  to
              locate the keyfile.  The default keyfile value is rsa.

              Zero  or  more  hostname  values  can be specified.  The default
              hostname is the value of myhostname main.cf parameter.

       output-server-tlsa [-h hostname] [keyfile...]
              Write to stdout a DANE TLSA RRset suitable for a  port  25  SMTP
              server on host hostname with keys from any of the specified key-
              file values.  The default hostname is the value of  the  myhost-
              name main.cf parameter.

              Instead  of  absolute  pathnames  or pathnames relative to $con-
              fig_directory, the keyfile list may specify names  of  supported
              public key algorithms (see "postconf -T public-key-algorithms").
              In that case, the actual keyfile list uses  the  values  of  the
              corresponding  Postfix  server  TLS  key  file parameters.  If a
              parameter value is empty or equal to none, then no  TLSA  record
              is output for that algorithm.

              The  default  keyfile  list  consists of the two supported algo-
              rithms rsa and ecdsa.

AUXILIARY COMMANDS
       all-default-client
              Exit with status 0 (success) if all SMTP client TLS settings are
              at their default values.  Otherwise, exit with a non-zero status.
              This is typically used as follows:

              postfix tls all-default-client &&
                      postfix tls enable-client

       all-default-server
              Exit with status 0 (success) if all SMTP server TLS settings are
              at their default values.  Otherwise, exit with a non-zero status.
              This is typically used as follows:

              postfix tls all-default-server &&
                      postfix tls enable-server

CONFIGURATION PARAMETERS
       The "postfix tls subcommand" feature reads  or  updates  the  following
       configuration parameters.

       command_directory (see 'postconf -d' output)
              The location of all postfix administrative commands.

       config_directory (see 'postconf -d' output)
              The  default  location of the Postfix main.cf and master.cf con-
              figuration files.

       openssl_path (openssl)
              The location of the OpenSSL command line program openssl(1).

       smtp_tls_loglevel (0)
              Enable additional Postfix SMTP client logging of TLS activity.

       smtp_tls_security_level (empty)
              The default SMTP TLS security level for the Postfix SMTP client;
              when a non-empty value is specified, this overrides the obsolete
              parameters       smtp_use_tls,       smtp_enforce_tls,       and
              smtp_tls_enforce_peername.

       smtp_tls_session_cache_database (empty)
              Name of the file containing the optional Postfix SMTP client TLS
              session cache.

       smtpd_tls_cert_file (empty)
              File with the Postfix SMTP server RSA certificate in PEM format.

       smtpd_tls_eccert_file (empty)
              File with the Postfix SMTP server ECDSA certificate in PEM  for-
              mat.

       smtpd_tls_eckey_file ($smtpd_tls_eccert_file)
              File  with the Postfix SMTP server ECDSA private key in PEM for-
              mat.

       smtpd_tls_key_file ($smtpd_tls_cert_file)
              File with the Postfix SMTP server RSA private key in PEM format.

       smtpd_tls_loglevel (0)
              Enable additional Postfix SMTP server logging of TLS activity.

       smtpd_tls_received_header (no)
              Request that the Postfix SMTP server produces Received:  message
              headers  that  include information about the protocol and cipher
              used, as well as the remote SMTP client  CommonName  and  client
              certificate issuer CommonName.

       smtpd_tls_security_level (empty)
              The  SMTP TLS security level for the Postfix SMTP server; when a
              non-empty value is specified, this overrides the obsolete param-
              eters smtpd_use_tls and smtpd_enforce_tls.

       tls_random_source (see 'postconf -d' output)
              The  external  entropy source for the in-memory tlsmgr(8) pseudo
              random number generator (PRNG) pool.


ATTRIBUTES
       See attributes(7) for descriptions of the following attributes:


       +---------------+------------------------------+
       |ATTRIBUTE TYPE |       ATTRIBUTE VALUE        |
       +---------------+------------------------------+
       |Availability   | service/network/smtp/postfix |
       +---------------+------------------------------+
       |Stability      | Volatile                     |
       +---------------+------------------------------+
SEE ALSO
       master(8) Postfix master program
       postfix(1) Postfix administrative interface

README FILES
       Use "postconf readme_directory" or "postconf html_directory" to  locate
       this information.
       TLS_README, Postfix TLS configuration and operation

LICENSE
       The Secure Mailer license must be distributed with this software.

HISTORY
       The "postfix tls" command was introduced with Postfix version 3.1.

AUTHOR(S)
       Viktor Dukhovni



NOTES
       This software was built from source available at
       https://github.com/oracle/solaris-userland.  The original community
       source was downloaded from  https://archive.mgm51.com/mirrors/postfix-
       source/official/postfix-3.2.2.tar.gz

       Further information about this software can be found on the open source
       community website at http://www.postfix.org.



                                                                POSTFIX-TLS(1)