man > postfix-tls(1)

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 parame‐
              ter (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-hh‐
              mmss.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 intermedi‐
              ate 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  algo‐
              rithm 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  cer‐
              tificate  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  configura‐
              tion 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-al‐
              gorithms"). 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  pub‐
              lic-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.

       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 Com‐
              monName 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)