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, sug-
gest 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, sug-
gest 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 cer-
tificates to make use of ECDSA with compatible clients and RSA
with the rest. If you want to deploy certificate chains with in-
termediate 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- in-
stead 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 name-
servers 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 certifi-
cate chain file. The server certificate must be the first cer-
tificate 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 un-
derlying public key algorithms may well be obsoleted by quantum
computers long before then.
The most plausible reason for using this command is when the sys-
tem 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 configuration directory.
output-server-csr [-k keyfile] [hostname...]
Write to stdout a certificate signing request (CSR) for the spec-
ified keyfile.
Instead of an absolute pathname or a pathname relative to $con-
fig_directory, keyfile may specify one of the supported key algo-
rithm 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 host-
name 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 myhostname
main.cf parameter.
Instead of absolute pathnames or pathnames relative to $con-
fig_directory, the keyfile list may specify names of supported
public key algorithms (see "postconf -T public-key-algorithms").
In that case, the actual keyfile list uses the values of the cor-
responding Postfix server TLS key file parameters. If a parame-
ter value is empty or equal to none, then no TLSA record is out-
put for that algorithm.
The default keyfile list consists of the two supported algorithms
rsa and ecdsa.
AUXILIARY COMMANDS
all-default-client
Exit with status 0 (success) if all SMTP client TLS settings are
at their default values. Otherwise, exit with a non-zero status.
This is typically used as follows:
postfix tls all-default-client &&
postfix tls enable-client
all-default-server
Exit with status 0 (success) if all SMTP server TLS settings are
at their default values. Otherwise, exit with a non-zero status.
This is typically used as follows:
postfix tls all-default-server &&
postfix tls enable-server
CONFIGURATION PARAMETERS
The "postfix tls subcommand" feature reads or updates the following con-
figuration parameters.
command_directory (see 'postconf -d' output)
The location of all postfix administrative commands.
config_directory (see 'postconf -d' output)
The default location of the Postfix main.cf and master.cf config-
uration files.
openssl_path (openssl)
The location of the OpenSSL command line program openssl(1).
smtp_tls_loglevel (0)
Enable additional Postfix SMTP client logging of TLS activity.
smtp_tls_security_level (empty)
The default SMTP TLS security level for the Postfix SMTP client.
smtp_tls_session_cache_database (empty)
Name of the file containing the optional Postfix SMTP client TLS
session cache.
smtpd_tls_cert_file (empty)
File with the Postfix SMTP server RSA certificate in PEM format.
smtpd_tls_eccert_file (empty)
File with the Postfix SMTP server ECDSA certificate in PEM for-
mat.
smtpd_tls_eckey_file ($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 parame-
ters 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)
Generated by dwww version 1.16 on Tue Dec 16 04:31:15 CET 2025.