Provided by: postfix_3.3.0-1ubuntu2_amd64 bug

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 commands 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 support 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  alternative 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 certificate  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 generating 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 certificates generated have
              a 100-year nominal expiration time.  The underlying public key algorithms may  well
              be obsoleted by quantum 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 certificate 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 certificates
              may be removed by hand.   The keyfile and certfile filenames 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 $config_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 keyfile values.  The default  hostname
              is the value of the myhostname main.cf parameter.

              Instead  of  absolute  pathnames  or  pathnames  relative to $config_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 algorithms 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 configuration 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 format.

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

       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   parameters   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.

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

                                                                                   POSTFIX-TLS(1)