TLSPROXY(8)                                                        TLSPROXY(8)

NAME
       tlsproxy - Postfix TLS proxy

SYNOPSIS
       tlsproxy [generic Postfix daemon options]

DESCRIPTION
       The  tlsproxy(8)  server  implements a two-way TLS proxy. It is used by
       the postscreen(8) server to talk SMTP-over-TLS with remote SMTP clients
       that  are not whitelisted (including clients whose whitelist status has
       expired), and by the smtp(8) client to support  TLS  connection  reuse,
       but it should also work for non-SMTP protocols.

       Although  one  tlsproxy(8)  process  can serve multiple sessions at the
       same time, it is a good idea  to  allow  the  number  of  processes  to
       increase with load, so that the service remains responsive.

PROTOCOL EXAMPLE
       The  example  below  concerns  postscreen(8).  However, the tlsproxy(8)
       server is agnostic of the application protocol, and the example is eas-
       ily adapted to other applications.

       After  receiving  a  valid  remote  SMTP  client  STARTTLS command, the
       postscreen(8) server sends the remote SMTP client endpoint string,  the
       requested  role  (server),  and  the  requested timeout to tlsproxy(8).
       postscreen(8)  then  receives  a  "TLS   available"   indication   from
       tlsproxy(8).   If the TLS service is available, postscreen(8) sends the
       remote SMTP client file descriptor to tlsproxy(8), and sends the plain-
       text 220 greeting to the remote SMTP client.  This triggers TLS negoti-
       ations between the remote SMTP client and tlsproxy(8).  Upon completion
       of  the  TLS-level  handshake, tlsproxy(8) translates between plaintext
       from/to postscreen(8) and ciphertext to/from the remote SMTP client.

SECURITY
       The tlsproxy(8) server is moderately security-sensitive.  It  talks  to
       untrusted  clients  on  the network. The process can be run chrooted at
       fixed low privilege.

DIAGNOSTICS
       Problems and transactions are logged to syslogd(8).

CONFIGURATION PARAMETERS
       Changes to main.cf are not picked up automatically, as tlsproxy(8) pro-
       cesses  may run for a long time depending on mail server load.  Use the
       command "postfix reload" to speed up a change.

       The text below provides only a parameter summary. See  postconf(5)  for
       more details including examples.

STARTTLS SUPPORT CONTROLS
       tlsproxy_tls_CAfile ($smtpd_tls_CAfile)
              A  file  containing  (PEM  format)  CA  certificates of root CAs
              trusted to sign either remote SMTP client certificates or inter-
              mediate CA certificates.

       tlsproxy_tls_CApath ($smtpd_tls_CApath)
              A  directory containing (PEM format) CA certificates of root CAs
              trusted to sign either remote SMTP client certificates or inter-
              mediate CA certificates.

       tlsproxy_tls_always_issue_session_ids     ($smtpd_tls_always_issue_ses-
       sion_ids)
              Force  the Postfix tlsproxy(8) server to issue a TLS session id,
              even when TLS session caching is turned off.

       tlsproxy_tls_ask_ccert ($smtpd_tls_ask_ccert)
              Ask a remote SMTP client for a client certificate.

       tlsproxy_tls_ccert_verifydepth ($smtpd_tls_ccert_verifydepth)
              The verification depth for remote SMTP client certificates.

       tlsproxy_tls_cert_file ($smtpd_tls_cert_file)
              File with the Postfix tlsproxy(8) server RSA certificate in  PEM
              format.

       tlsproxy_tls_ciphers ($smtpd_tls_ciphers)
              The minimum TLS cipher grade that the Postfix tlsproxy(8) server
              will use with opportunistic TLS encryption.

       tlsproxy_tls_dcert_file ($smtpd_tls_dcert_file)
              File with the Postfix tlsproxy(8) server DSA certificate in  PEM
              format.

       tlsproxy_tls_dh1024_param_file ($smtpd_tls_dh1024_param_file)
              File  with  DH  parameters  that  the Postfix tlsproxy(8) server
              should use with non-export EDH ciphers.

       tlsproxy_tls_dh512_param_file ($smtpd_tls_dh512_param_file)
              File with DH parameters  that  the  Postfix  tlsproxy(8)  server
              should use with export-grade EDH ciphers.

       tlsproxy_tls_dkey_file ($smtpd_tls_dkey_file)
              File  with the Postfix tlsproxy(8) server DSA private key in PEM
              format.

       tlsproxy_tls_eccert_file ($smtpd_tls_eccert_file)
              File with the Postfix tlsproxy(8) server  ECDSA  certificate  in
              PEM format.

       tlsproxy_tls_eckey_file ($smtpd_tls_eckey_file)
              File  with  the  Postfix tlsproxy(8) server ECDSA private key in
              PEM format.

       tlsproxy_tls_eecdh_grade ($smtpd_tls_eecdh_grade)
              The Postfix tlsproxy(8)  server  security  grade  for  ephemeral
              elliptic-curve Diffie-Hellman (EECDH) key exchange.

       tlsproxy_tls_exclude_ciphers ($smtpd_tls_exclude_ciphers)
              List  of ciphers or cipher types to exclude from the tlsproxy(8)
              server cipher list at all TLS security levels.

       tlsproxy_tls_fingerprint_digest ($smtpd_tls_fingerprint_digest)
              The  message  digest  algorithm   to   construct   remote   SMTP
              client-certificate fingerprints.

       tlsproxy_tls_key_file ($smtpd_tls_key_file)
              File  with the Postfix tlsproxy(8) server RSA private key in PEM
              format.

       tlsproxy_tls_loglevel ($smtpd_tls_loglevel)
              Enable additional Postfix  tlsproxy(8)  server  logging  of  TLS
              activity.

       tlsproxy_tls_mandatory_ciphers ($smtpd_tls_mandatory_ciphers)
              The minimum TLS cipher grade that the Postfix tlsproxy(8) server
              will use with mandatory TLS encryption.

       tlsproxy_tls_mandatory_exclude_ciphers               ($smtpd_tls_manda-
       tory_exclude_ciphers)
              Additional list of ciphers or cipher types to exclude  from  the
              tlsproxy(8) server cipher list at mandatory TLS security levels.

       tlsproxy_tls_mandatory_protocols ($smtpd_tls_mandatory_protocols)
              The SSL/TLS protocols accepted by the Postfix tlsproxy(8) server
              with mandatory TLS encryption.

       tlsproxy_tls_protocols ($smtpd_tls_protocols)
              List  of  TLS protocols that the Postfix tlsproxy(8) server will
              exclude or include with opportunistic TLS encryption.

       tlsproxy_tls_req_ccert ($smtpd_tls_req_ccert)
              With mandatory TLS encryption, require  a  trusted  remote  SMTP
              client certificate in order to allow TLS connections to proceed.

       tlsproxy_tls_security_level ($smtpd_tls_security_level)
              The SMTP TLS security level for the Postfix tlsproxy(8)  server;
              when a non-empty value is specified, this overrides the obsolete
              parameters smtpd_use_tls and smtpd_enforce_tls.

       Available in Postfix version 2.11 and later:

       tlsmgr_service_name (tlsmgr)
              The name of the tlsmgr(8) service entry in master.cf.

OBSOLETE STARTTLS SUPPORT CONTROLS
       These parameters are supported for compatibility with  smtpd(8)  legacy
       parameters.

       tlsproxy_use_tls ($smtpd_use_tls)
              Opportunistic  TLS:  announce  STARTTLS  support  to remote SMTP
              clients, but do not require that clients use TLS encryption.

       tlsproxy_enforce_tls ($smtpd_enforce_tls)
              Mandatory TLS: announce STARTTLS support to remote SMTP clients,
              and require that clients use TLS encryption.

RESOURCE CONTROLS
       tlsproxy_watchdog_timeout (10s)
              How much time a tlsproxy(8) process may take to process local or
              remote I/O before it is terminated by a built-in watchdog timer.

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

       process_id (read-only)
              The process ID of a Postfix command or daemon process.

       process_name (read-only)
              The process name of a Postfix command or daemon process.

       syslog_facility (mail)
              The syslog facility of Postfix logging.

       syslog_name (see 'postconf -d' output)
              A prefix that  is  prepended  to  the  process  name  in  syslog
              records, so that, for example, "smtpd" becomes "prefix/smtpd".

       Available in Postfix 3.3 and later:

       service_name (read-only)
              The master.cf service name of a Postfix daemon process.

SEE ALSO
       postscreen(8), Postfix zombie blocker
       smtpd(8), Postfix SMTP server
       postconf(5), configuration parameters
       syslogd(5), system logging

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

HISTORY
       This service was introduced with Postfix version 2.8.

AUTHOR(S)
       Wietse Venema
       IBM T.J. Watson Research
       P.O. Box 704
       Yorktown Heights, NY 10598, USA

       Wietse Venema
       Google, Inc.
       111 8th Avenue
       New York, NY 10011, USA

                                                                   TLSPROXY(8)