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netbsd/external/ibm-public/postfix/dist/html/tlsproxy.8.html
2013-04-06 16:48:33 +02:00

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<title> Postfix manual - tlsproxy(8) </title>
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TLSPROXY(8) TLSPROXY(8)
<b>NAME</b>
tlsproxy - Postfix TLS proxy
<b>SYNOPSIS</b>
<b>tlsproxy</b> [generic Postfix daemon options]
<b>DESCRIPTION</b>
The <a href="tlsproxy.8.html"><b>tlsproxy</b>(8)</a> server implements a server-side TLS proxy.
It is used by <a href="postscreen.8.html"><b>postscreen</b>(8)</a> to talk SMTP-over-TLS with
remote SMTP clients whose whitelist status has expired,
but it should also work for non-SMTP protocols.
Although one <a href="tlsproxy.8.html"><b>tlsproxy</b>(8)</a> process can serve multiple ses-
sions 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.
<b>PROTOCOL EXAMPLE</b>
The example below concerns <a href="postscreen.8.html"><b>postscreen</b>(8)</a>. However, the
<a href="tlsproxy.8.html"><b>tlsproxy</b>(8)</a> server is agnostic of the application proto-
col, and the example is easily adapted to other applica-
tions.
The <a href="postscreen.8.html"><b>postscreen</b>(8)</a> server sends the remote SMTP client end-
point string, the requested role (server), and the
requested timeout to <a href="tlsproxy.8.html"><b>tlsproxy</b>(8)</a>. <a href="postscreen.8.html"><b>postscreen</b>(8)</a> then
receives a "TLS available" indication from <a href="tlsproxy.8.html"><b>tlsproxy</b>(8)</a>.
If the TLS service is available, <a href="postscreen.8.html"><b>postscreen</b>(8)</a> sends the
remote SMTP client file descriptor to <a href="tlsproxy.8.html"><b>tlsproxy</b>(8)</a>, and
sends the plaintext 220 greeting to the remote SMTP
client. This triggers TLS negotiations between the remote
SMTP client and <a href="tlsproxy.8.html"><b>tlsproxy</b>(8)</a>. Upon completion of the TLS-
level handshake, <a href="tlsproxy.8.html"><b>tlsproxy</b>(8)</a> translates between plaintext
from/to <a href="postscreen.8.html"><b>postscreen</b>(8)</a> and ciphertext to/from the remote
SMTP client.
<b>SECURITY</b>
The <a href="tlsproxy.8.html"><b>tlsproxy</b>(8)</a> server is moderately security-sensitive.
It talks to untrusted clients on the network. The process
can be run chrooted at fixed low privilege.
<b>DIAGNOSTICS</b>
Problems and transactions are logged to <b>syslogd</b>(8).
<b>CONFIGURATION PARAMETERS</b>
Changes to <a href="postconf.5.html"><b>main.cf</b></a> are not picked up automatically, as
<a href="tlsproxy.8.html"><b>tlsproxy</b>(8)</a> processes may run for a long time depending on
mail server load. Use the command "<b>postfix reload</b>" to
speed up a change.
The text below provides only a parameter summary. See
<a href="postconf.5.html"><b>postconf</b>(5)</a> for more details including examples.
<b>STARTTLS SUPPORT CONTROLS</b>
<b><a href="postconf.5.html#tlsproxy_tls_CAfile">tlsproxy_tls_CAfile</a> ($<a href="postconf.5.html#smtpd_tls_CAfile">smtpd_tls_CAfile</a>)</b>
A file containing (PEM format) CA certificates of
root CAs trusted to sign either remote SMTP client
certificates or intermediate CA certificates.
<b><a href="postconf.5.html#tlsproxy_tls_CApath">tlsproxy_tls_CApath</a> ($<a href="postconf.5.html#smtpd_tls_CApath">smtpd_tls_CApath</a>)</b>
A directory containing (PEM format) CA certificates
of root CAs trusted to sign either remote SMTP
client certificates or intermediate CA certifi-
cates.
<b><a href="postconf.5.html#tlsproxy_tls_always_issue_session_ids">tlsproxy_tls_always_issue_session_ids</a></b>
<b>($<a href="postconf.5.html#smtpd_tls_always_issue_session_ids">smtpd_tls_always_issue_session_ids</a>)</b>
Force the Postfix <a href="tlsproxy.8.html"><b>tlsproxy</b>(8)</a> server to issue a TLS
session id, even when TLS session caching is turned
off.
<b><a href="postconf.5.html#tlsproxy_tls_ask_ccert">tlsproxy_tls_ask_ccert</a> ($<a href="postconf.5.html#smtpd_tls_ask_ccert">smtpd_tls_ask_ccert</a>)</b>
Ask a remote SMTP client for a client certificate.
<b><a href="postconf.5.html#tlsproxy_tls_ccert_verifydepth">tlsproxy_tls_ccert_verifydepth</a> ($<a href="postconf.5.html#smtpd_tls_ccert_verifydepth">smtpd_tls_ccert_verify</a>-</b>
<b><a href="postconf.5.html#smtpd_tls_ccert_verifydepth">depth</a>)</b>
The verification depth for remote SMTP client cer-
tificates.
<b><a href="postconf.5.html#tlsproxy_tls_cert_file">tlsproxy_tls_cert_file</a> ($<a href="postconf.5.html#smtpd_tls_cert_file">smtpd_tls_cert_file</a>)</b>
File with the Postfix <a href="tlsproxy.8.html"><b>tlsproxy</b>(8)</a> server RSA cer-
tificate in PEM format.
<b><a href="postconf.5.html#tlsproxy_tls_ciphers">tlsproxy_tls_ciphers</a> ($<a href="postconf.5.html#smtpd_tls_ciphers">smtpd_tls_ciphers</a>)</b>
The minimum TLS cipher grade that the Postfix
<a href="tlsproxy.8.html"><b>tlsproxy</b>(8)</a> server will use with opportunistic TLS
encryption.
<b><a href="postconf.5.html#tlsproxy_tls_dcert_file">tlsproxy_tls_dcert_file</a> ($<a href="postconf.5.html#smtpd_tls_dcert_file">smtpd_tls_dcert_file</a>)</b>
File with the Postfix <a href="tlsproxy.8.html"><b>tlsproxy</b>(8)</a> server DSA cer-
tificate in PEM format.
<b><a href="postconf.5.html#tlsproxy_tls_dh1024_param_file">tlsproxy_tls_dh1024_param_file</a></b>
<b>($<a href="postconf.5.html#smtpd_tls_dh1024_param_file">smtpd_tls_dh1024_param_file</a>)</b>
File with DH parameters that the Postfix
<a href="tlsproxy.8.html"><b>tlsproxy</b>(8)</a> server should use with EDH ciphers.
<b><a href="postconf.5.html#tlsproxy_tls_dh512_param_file">tlsproxy_tls_dh512_param_file</a></b>
<b>($<a href="postconf.5.html#smtpd_tls_dh512_param_file">smtpd_tls_dh512_param_file</a>)</b>
File with DH parameters that the Postfix
<a href="tlsproxy.8.html"><b>tlsproxy</b>(8)</a> server should use with EDH ciphers.
<b><a href="postconf.5.html#tlsproxy_tls_dkey_file">tlsproxy_tls_dkey_file</a> ($<a href="postconf.5.html#smtpd_tls_dkey_file">smtpd_tls_dkey_file</a>)</b>
File with the Postfix <a href="tlsproxy.8.html"><b>tlsproxy</b>(8)</a> server DSA pri-
vate key in PEM format.
<b><a href="postconf.5.html#tlsproxy_tls_eccert_file">tlsproxy_tls_eccert_file</a> ($<a href="postconf.5.html#smtpd_tls_eccert_file">smtpd_tls_eccert_file</a>)</b>
File with the Postfix <a href="tlsproxy.8.html"><b>tlsproxy</b>(8)</a> server ECDSA cer-
tificate in PEM format.
<b><a href="postconf.5.html#tlsproxy_tls_eckey_file">tlsproxy_tls_eckey_file</a> ($<a href="postconf.5.html#smtpd_tls_eckey_file">smtpd_tls_eckey_file</a>)</b>
File with the Postfix <a href="tlsproxy.8.html"><b>tlsproxy</b>(8)</a> server ECDSA pri-
vate key in PEM format.
<b><a href="postconf.5.html#tlsproxy_tls_eecdh_grade">tlsproxy_tls_eecdh_grade</a> ($<a href="postconf.5.html#smtpd_tls_eecdh_grade">smtpd_tls_eecdh_grade</a>)</b>
The Postfix <a href="tlsproxy.8.html"><b>tlsproxy</b>(8)</a> server security grade for
ephemeral elliptic-curve Diffie-Hellman (EECDH) key
exchange.
<b><a href="postconf.5.html#tlsproxy_tls_exclude_ciphers">tlsproxy_tls_exclude_ciphers</a> ($<a href="postconf.5.html#smtpd_tls_exclude_ciphers">smtpd_tls_exclude_ciphers</a>)</b>
List of ciphers or cipher types to exclude from the
<a href="tlsproxy.8.html"><b>tlsproxy</b>(8)</a> server cipher list at all TLS security
levels.
<b><a href="postconf.5.html#tlsproxy_tls_fingerprint_digest">tlsproxy_tls_fingerprint_digest</a> ($<a href="postconf.5.html#smtpd_tls_fingerprint_digest">smtpd_tls_finger</a>-</b>
<b><a href="postconf.5.html#smtpd_tls_fingerprint_digest">print_digest</a>)</b>
The message digest algorithm used to construct
client-certificate fingerprints.
<b><a href="postconf.5.html#tlsproxy_tls_key_file">tlsproxy_tls_key_file</a> ($<a href="postconf.5.html#smtpd_tls_key_file">smtpd_tls_key_file</a>)</b>
File with the Postfix <a href="tlsproxy.8.html"><b>tlsproxy</b>(8)</a> server RSA pri-
vate key in PEM format.
<b><a href="postconf.5.html#tlsproxy_tls_loglevel">tlsproxy_tls_loglevel</a> ($<a href="postconf.5.html#smtpd_tls_loglevel">smtpd_tls_loglevel</a>)</b>
Enable additional Postfix <a href="tlsproxy.8.html"><b>tlsproxy</b>(8)</a> server log-
ging of TLS activity.
<b><a href="postconf.5.html#tlsproxy_tls_mandatory_ciphers">tlsproxy_tls_mandatory_ciphers</a> ($<a href="postconf.5.html#smtpd_tls_mandatory_ciphers">smtpd_tls_manda</a>-</b>
<b><a href="postconf.5.html#smtpd_tls_mandatory_ciphers">tory_ciphers</a>)</b>
The minimum TLS cipher grade that the Postfix
<a href="tlsproxy.8.html"><b>tlsproxy</b>(8)</a> server will use with mandatory TLS
encryption.
<b><a href="postconf.5.html#tlsproxy_tls_mandatory_exclude_ciphers">tlsproxy_tls_mandatory_exclude_ciphers</a> ($<a href="postconf.5.html#smtpd_tls_mandatory_exclude_ciphers">smtpd_tls_manda</a>-</b>
<b><a href="postconf.5.html#smtpd_tls_mandatory_exclude_ciphers">tory_exclude_ciphers</a>)</b>
Additional list of ciphers or cipher types to
exclude from the <a href="tlsproxy.8.html"><b>tlsproxy</b>(8)</a> server cipher list at
mandatory TLS security levels.
<b><a href="postconf.5.html#tlsproxy_tls_mandatory_protocols">tlsproxy_tls_mandatory_protocols</a> ($<a href="postconf.5.html#smtpd_tls_mandatory_protocols">smtpd_tls_manda</a>-</b>
<b><a href="postconf.5.html#smtpd_tls_mandatory_protocols">tory_protocols</a>)</b>
The SSL/TLS protocols accepted by the Postfix
<a href="tlsproxy.8.html"><b>tlsproxy</b>(8)</a> server with mandatory TLS encryption.
<b><a href="postconf.5.html#tlsproxy_tls_protocols">tlsproxy_tls_protocols</a> ($<a href="postconf.5.html#smtpd_tls_protocols">smtpd_tls_protocols</a>)</b>
List of TLS protocols that the Postfix <a href="tlsproxy.8.html"><b>tlsproxy</b>(8)</a>
server will exclude or include with opportunistic
TLS encryption.
<b><a href="postconf.5.html#tlsproxy_tls_req_ccert">tlsproxy_tls_req_ccert</a> ($<a href="postconf.5.html#smtpd_tls_req_ccert">smtpd_tls_req_ccert</a>)</b>
With mandatory TLS encryption, require a trusted
remote SMTP client certificate in order to allow
TLS connections to proceed.
<b><a href="postconf.5.html#tlsproxy_tls_security_level">tlsproxy_tls_security_level</a> ($<a href="postconf.5.html#smtpd_tls_security_level">smtpd_tls_security_level</a>)</b>
The SMTP TLS security level for the Postfix
<a href="tlsproxy.8.html"><b>tlsproxy</b>(8)</a> server; when a non-empty value is spec-
ified, this overrides the obsolete parameters
<a href="postconf.5.html#smtpd_use_tls">smtpd_use_tls</a> and <a href="postconf.5.html#smtpd_enforce_tls">smtpd_enforce_tls</a>.
<b><a href="postconf.5.html#tlsproxy_tls_session_cache_timeout">tlsproxy_tls_session_cache_timeout</a> ($<a href="postconf.5.html#smtpd_tls_session_cache_timeout">smtpd_tls_ses</a>-</b>
<b><a href="postconf.5.html#smtpd_tls_session_cache_timeout">sion_cache_timeout</a>)</b>
The expiration time of Postfix <a href="tlsproxy.8.html"><b>tlsproxy</b>(8)</a> server
TLS session cache information.
<b>OBSOLETE STARTTLS SUPPORT CONTROLS</b>
These parameters are supported for compatibility with
<a href="smtpd.8.html"><b>smtpd</b>(8)</a> legacy parameters.
<b><a href="postconf.5.html#tlsproxy_use_tls">tlsproxy_use_tls</a> ($<a href="postconf.5.html#smtpd_use_tls">smtpd_use_tls</a>)</b>
Opportunistic TLS: announce STARTTLS support to
SMTP clients, but do not require that clients use
TLS encryption.
<b><a href="postconf.5.html#tlsproxy_enforce_tls">tlsproxy_enforce_tls</a> ($<a href="postconf.5.html#smtpd_enforce_tls">smtpd_enforce_tls</a>)</b>
Mandatory TLS: announce STARTTLS support to SMTP
clients, and require that clients use TLS encryp-
tion.
<b>RESOURCE CONTROLS</b>
<b><a href="postconf.5.html#tlsproxy_watchdog_timeout">tlsproxy_watchdog_timeout</a> (10s)</b>
How much time a <a href="tlsproxy.8.html"><b>tlsproxy</b>(8)</a> process may take to
process local or remote I/O before it is terminated
by a built-in watchdog timer.
<b>MISCELLANEOUS CONTROLS</b>
<b><a href="postconf.5.html#config_directory">config_directory</a> (see 'postconf -d' output)</b>
The default location of the Postfix <a href="postconf.5.html">main.cf</a> and
<a href="master.5.html">master.cf</a> configuration files.
<b><a href="postconf.5.html#process_id">process_id</a> (read-only)</b>
The process ID of a Postfix command or daemon
process.
<b><a href="postconf.5.html#process_name">process_name</a> (read-only)</b>
The process name of a Postfix command or daemon
process.
<b><a href="postconf.5.html#syslog_facility">syslog_facility</a> (mail)</b>
The syslog facility of Postfix logging.
<b><a href="postconf.5.html#syslog_name">syslog_name</a> (see 'postconf -d' output)</b>
The mail system name that is prepended to the
process name in syslog records, so that "smtpd"
becomes, for example, "postfix/smtpd".
<b>SEE ALSO</b>
<a href="postscreen.8.html">postscreen(8)</a>, Postfix zombie blocker
<a href="smtpd.8.html">smtpd(8)</a>, Postfix SMTP server
<a href="postconf.5.html">postconf(5)</a>, configuration parameters
syslogd(5), system logging
<b>LICENSE</b>
The Secure Mailer license must be distributed with this
software.
<b>HISTORY</b>
This service was introduced with Postfix version 2.8.
<b>AUTHOR(S)</b>
Wietse Venema
IBM T.J. Watson Research
P.O. Box 704
Yorktown Heights, NY 10598, USA
TLSPROXY(8)
</pre> </body> </html>