1SMTP(8) System Manager's Manual SMTP(8)
2
6 smtp - Postfix SMTP+LMTP client
7
9 smtp [generic Postfix daemon options]
10
12 The Postfix SMTP+LMTP client implements the SMTP and LMTP mail delivery
13 protocols. It processes message delivery requests from the queue man‐
14 ager. Each request specifies a queue file, a sender address, a domain
15 or host to deliver to, and recipient information. This program expects
16 to be run from the master(8) process manager.
17 The SMTP+LMTP client updates the queue file and marks recipients as
19 finished, or it informs the queue manager that delivery should be tried
20 again at a later time. Delivery status reports are sent to the
21 bounce(8), defer(8) or trace(8) daemon as appropriate.
22 The SMTP+LMTP client looks up a list of mail exchanger addresses for
24 the destination host, sorts the list by preference, and connects to
25 each listed address until it finds a server that responds.
26 When a server is not reachable, or when mail delivery fails due to a
28 recoverable error condition, the SMTP+LMTP client will try to deliver
29 the mail to an alternate host.
30 After a successful mail transaction, a connection may be saved to the
32 scache(8) connection cache server, so that it may be used by any
33 SMTP+LMTP client for a subsequent transaction.
34 By default, connection caching is enabled temporarily for destinations
36 that have a high volume of mail in the active queue. Connection caching
37 can be enabled permanently for specific destinations.
38
40 SMTP destinations have the following form:
41 domainname
43 domainname:port
45 Look up the mail exchangers for the specified domain, and con‐
46 nect to the specified port (default: smtp).
47 [hostname]
49 [hostname]:port
51 Look up the address(es) of the specified host, and connect to
52 the specified port (default: smtp).
53 [address]
55 [address]:port
57 Connect to the host at the specified address, and connect to the
58 specified port (default: smtp). An IPv6 address must be format‐
59 ted as [ipv6:address].
60
62 LMTP destinations have the following form:
63 unix:pathname
65 Connect to the local UNIX-domain server that is bound to the
66 specified pathname. If the process runs chrooted, an absolute
67 pathname is interpreted relative to the Postfix queue directory.
68 inet:hostname
70 inet:hostname:port
72 inet:[address]
74 inet:[address]:port
76 Connect to the specified TCP port on the specified local or
77 remote host. If no port is specified, connect to the port
78 defined as lmtp in services(4). If no such service is found,
79 the lmtp_tcp_port configuration parameter (default value of 24)
80 will be used. An IPv6 address must be formatted as
81 [ipv6:address].
82
84 The SMTP+LMTP client is moderately security-sensitive. It talks to SMTP
85 or LMTP servers and to DNS servers on the network. The SMTP+LMTP client
86 can be run chrooted at fixed low privilege.
87
89 RFC 821 (SMTP protocol)
90 RFC 822 (ARPA Internet Text Messages)
91 RFC 1651 (SMTP service extensions)
92 RFC 1652 (8bit-MIME transport)
93 RFC 1870 (Message Size Declaration)
94 RFC 2033 (LMTP protocol)
95 RFC 2034 (SMTP Enhanced Error Codes)
96 RFC 2045 (MIME: Format of Internet Message Bodies)
97 RFC 2046 (MIME: Media Types)
98 RFC 2554 (AUTH command)
99 RFC 2821 (SMTP protocol)
100 RFC 2920 (SMTP Pipelining)
101 RFC 3207 (STARTTLS command)
102 RFC 3461 (SMTP DSN Extension)
103 RFC 3463 (Enhanced Status Codes)
104 RFC 4954 (AUTH command)
105
107 Problems and transactions are logged to syslogd(8). Corrupted message
108 files are marked so that the queue manager can move them to the corrupt
109 queue for further inspection.
110 Depending on the setting of the notify_classes parameter, the postmas‐
112 ter is notified of bounces, protocol problems, and of other trouble.
113
115 SMTP and LMTP connection caching does not work with TLS. The necessary
116 support for TLS object passivation and re-activation does not exist
117 without closing the session, which defeats the purpose.
118 SMTP and LMTP connection caching assumes that SASL credentials are
120 valid for all destinations that map onto the same IP address and TCP
121 port.
122
124 Before Postfix version 2.3, the LMTP client is a separate program that
125 implements only a subset of the functionality available with SMTP:
126 there is no support for TLS, and connections are cached in-process,
127 making it ineffective when the client is used for multiple domains.
128 Most smtp_xxx configuration parameters have an lmtp_xxx "mirror" param‐
130 eter for the equivalent LMTP feature. This document describes only
131 those LMTP-related parameters that aren't simply "mirror" parameters.
132 Changes to main.cf are picked up automatically, as smtp(8) processes
134 run for only a limited amount of time. Use the command "postfix reload"
135 to speed up a change.
136 The text below provides only a parameter summary. See postconf(5) for
138 more details including examples.
139
141 ignore_mx_lookup_error (no)
142 Ignore DNS MX lookups that produce no response.
143 smtp_always_send_ehlo (yes)
145 Always send EHLO at the start of an SMTP session.
146 smtp_never_send_ehlo (no)
148 Never send EHLO at the start of an SMTP session.
149 smtp_defer_if_no_mx_address_found (no)
151 Defer mail delivery when no MX record resolves to an IP address.
152 smtp_line_length_limit (990)
154 The maximal length of message header and body lines that Postfix
155 will send via SMTP.
156 smtp_pix_workaround_delay_time (10s)
158 How long the Postfix SMTP client pauses before sending
159 ".<CR><LF>" in order to work around the PIX firewall
160 "<CR><LF>.<CR><LF>" bug.
161 smtp_pix_workaround_threshold_time (500s)
163 How long a message must be queued before the Postfix SMTP client
164 turns on the PIX firewall "<CR><LF>.<CR><LF>" bug workaround for
165 delivery through firewalls with "smtp fixup" mode turned on.
166 smtp_pix_workarounds (disable_esmtp, delay_dotcrlf)
168 A list that specifies zero or more workarounds for CISCO PIX
169 firewall bugs.
170 smtp_pix_workaround_maps (empty)
172 Lookup tables, indexed by the remote SMTP server address, with
173 per-destination workarounds for CISCO PIX firewall bugs.
174 smtp_quote_rfc821_envelope (yes)
176 Quote addresses in SMTP MAIL FROM and RCPT TO commands as
177 required by RFC 2821.
178 smtp_skip_5xx_greeting (yes)
180 Skip SMTP servers that greet with a 5XX status code (go away, do
181 not try again later).
182 smtp_skip_quit_response (yes)
184 Do not wait for the response to the SMTP QUIT command.
185 Available in Postfix version 2.0 and earlier:
187 smtp_skip_4xx_greeting (yes)
189 Skip SMTP servers that greet with a 4XX status code (go away,
190 try again later).
191 Available in Postfix version 2.2 and later:
193 smtp_discard_ehlo_keyword_address_maps (empty)
195 Lookup tables, indexed by the remote SMTP server address, with
196 case insensitive lists of EHLO keywords (pipelining, starttls,
197 auth, etc.) that the Postfix SMTP client will ignore in the EHLO
198 response from a remote SMTP server.
199 smtp_discard_ehlo_keywords (empty)
201 A case insensitive list of EHLO keywords (pipelining, starttls,
202 auth, etc.) that the Postfix SMTP client will ignore in the EHLO
203 response from a remote SMTP server.
204 smtp_generic_maps (empty)
206 Optional lookup tables that perform address rewriting in the
207 SMTP client, typically to transform a locally valid address into
208 a globally valid address when sending mail across the Internet.
209 Available in Postfix version 2.2.9 and later:
211 smtp_cname_overrides_servername (version dependent)
213 Allow DNS CNAME records to override the servername that the
214 Postfix SMTP client uses for logging, SASL password lookup, TLS
215 policy decisions, or TLS certificate verification.
216 Available in Postfix version 2.3 and later:
218 lmtp_discard_lhlo_keyword_address_maps (empty)
220 Lookup tables, indexed by the remote LMTP server address, with
221 case insensitive lists of LHLO keywords (pipelining, starttls,
222 auth, etc.) that the LMTP client will ignore in the LHLO
223 response from a remote LMTP server.
224 lmtp_discard_lhlo_keywords (empty)
226 A case insensitive list of LHLO keywords (pipelining, starttls,
227 auth, etc.) that the LMTP client will ignore in the LHLO
228 response from a remote LMTP server.
229 Available in Postfix version 2.4.4 and later:
231 send_cyrus_sasl_authzid (no)
233 When authenticating to a remote SMTP or LMTP server with the
234 default setting "no", send no SASL authoriZation ID (authzid);
235 send only the SASL authentiCation ID (authcid) plus the auth‐
236 cid's password.
237 Available in Postfix version 2.5 and later:
239 smtp_header_checks (empty)
241 Restricted header_checks(5) tables for the Postfix SMTP client.
242 smtp_mime_header_checks (empty)
244 Restricted mime_header_checks(5) tables for the Postfix SMTP
245 client.
246 smtp_nested_header_checks (empty)
248 Restricted nested_header_checks(5) tables for the Postfix SMTP
249 client.
250 smtp_body_checks (empty)
252 Restricted body_checks(5) tables for the Postfix SMTP client.
253 Available in Postfix version 2.6 and later:
255 tcp_windowsize (0)
257 An optional workaround for routers that break TCP window scal‐
258 ing.
259
261 Available in Postfix version 2.0 and later:
262 disable_mime_output_conversion (no)
264 Disable the conversion of 8BITMIME format to 7BIT format.
265 mime_boundary_length_limit (2048)
267 The maximal length of MIME multipart boundary strings.
268 mime_nesting_limit (100)
270 The maximal recursion level that the MIME processor will handle.
271
273 Available in Postfix version 2.1 and later:
274 smtp_send_xforward_command (no)
276 Send the non-standard XFORWARD command when the Postfix SMTP
277 server EHLO response announces XFORWARD support.
278
280 smtp_sasl_auth_enable (no)
281 Enable SASL authentication in the Postfix SMTP client.
282 smtp_sasl_password_maps (empty)
284 Optional SMTP client lookup tables with one username:password
285 entry per remote hostname or domain, or sender address when
286 sender-dependent authentication is enabled.
287 smtp_sasl_security_options (noplaintext, noanonymous)
289 Postfix SMTP client SASL security options; as of Postfix 2.3 the
290 list of available features depends on the SASL client implemen‐
291 tation that is selected with smtp_sasl_type.
292 Available in Postfix version 2.2 and later:
294 smtp_sasl_mechanism_filter (empty)
296 If non-empty, a Postfix SMTP client filter for the remote SMTP
297 server's list of offered SASL mechanisms.
298 Available in Postfix version 2.3 and later:
300 smtp_sender_dependent_authentication (no)
302 Enable sender-dependent authentication in the Postfix SMTP
303 client; this is available only with SASL authentication, and
304 disables SMTP connection caching to ensure that mail from dif‐
305 ferent senders will use the appropriate credentials.
306 smtp_sasl_path (empty)
308 Implementation-specific information that the Postfix SMTP client
309 passes through to the SASL plug-in implementation that is
310 selected with smtp_sasl_type.
311 smtp_sasl_type (cyrus)
313 The SASL plug-in type that the Postfix SMTP client should use
314 for authentication.
315 Available in Postfix version 2.5 and later:
317 smtp_sasl_auth_cache_name (empty)
319 An optional table to prevent repeated SASL authentication fail‐
320 ures with the same remote SMTP server hostname, username and
321 password.
322 smtp_sasl_auth_cache_time (90d)
324 The maximal age of an smtp_sasl_auth_cache_name entry before it
325 is removed.
326 smtp_sasl_auth_soft_bounce (yes)
328 When a remote SMTP server rejects a SASL authentication request
329 with a 535 reply code, defer mail delivery instead of returning
330 mail as undeliverable.
331
333 Detailed information about STARTTLS configuration may be found in the
334 TLS_README document.
335 smtp_tls_security_level (empty)
337 The default SMTP TLS security level for the Postfix SMTP client;
338 when a non-empty value is specified, this overrides the obsolete
339 parameters smtp_use_tls, smtp_enforce_tls, and
340 smtp_tls_enforce_peername.
341 smtp_sasl_tls_security_options ($smtp_sasl_security_options)
343 The SASL authentication security options that the Postfix SMTP
344 client uses for TLS encrypted SMTP sessions.
345 smtp_starttls_timeout (300s)
347 Time limit for Postfix SMTP client write and read operations
348 during TLS startup and shutdown handshake procedures.
349 smtp_tls_CAfile (empty)
351 A file containing CA certificates of root CAs trusted to sign
352 either remote SMTP server certificates or intermediate CA cer‐
353 tificates.
354 smtp_tls_CApath (empty)
356 Directory with PEM format certificate authority certificates
357 that the Postfix SMTP client uses to verify a remote SMTP server
358 certificate.
359 smtp_tls_cert_file (empty)
361 File with the Postfix SMTP client RSA certificate in PEM format.
362 smtp_tls_mandatory_ciphers (medium)
364 The minimum TLS cipher grade that the Postfix SMTP client will
365 use with mandatory TLS encryption.
366 smtp_tls_exclude_ciphers (empty)
368 List of ciphers or cipher types to exclude from the Postfix SMTP
369 client cipher list at all TLS security levels.
370 smtp_tls_mandatory_exclude_ciphers (empty)
372 Additional list of ciphers or cipher types to exclude from the
373 SMTP client cipher list at mandatory TLS security levels.
374 smtp_tls_dcert_file (empty)
376 File with the Postfix SMTP client DSA certificate in PEM format.
377 smtp_tls_dkey_file ($smtp_tls_dcert_file)
379 File with the Postfix SMTP client DSA private key in PEM format.
380 smtp_tls_key_file ($smtp_tls_cert_file)
382 File with the Postfix SMTP client RSA private key in PEM format.
383 smtp_tls_loglevel (0)
385 Enable additional Postfix SMTP client logging of TLS activity.
386 smtp_tls_note_starttls_offer (no)
388 Log the hostname of a remote SMTP server that offers STARTTLS,
389 when TLS is not already enabled for that server.
390 smtp_tls_policy_maps (empty)
392 Optional lookup tables with the Postfix SMTP client TLS security
393 policy by next-hop destination; when a non-empty value is speci‐
394 fied, this overrides the obsolete smtp_tls_per_site parameter.
395 smtp_tls_mandatory_protocols (SSLv3, TLSv1)
397 List of SSL/TLS protocols that the Postfix SMTP client will use
398 with mandatory TLS encryption.
399 smtp_tls_scert_verifydepth (9)
401 The verification depth for remote SMTP server certificates.
402 smtp_tls_secure_cert_match (nexthop, dot-nexthop)
404 The server certificate peername verification method for the
405 "secure" TLS security level.
406 smtp_tls_session_cache_database (empty)
408 Name of the file containing the optional Postfix SMTP client TLS
409 session cache.
410 smtp_tls_session_cache_timeout (3600s)
412 The expiration time of Postfix SMTP client TLS session cache
413 information.
414 smtp_tls_verify_cert_match (hostname)
416 The server certificate peername verification method for the
417 "verify" TLS security level.
418 tls_daemon_random_bytes (32)
420 The number of pseudo-random bytes that an smtp(8) or smtpd(8)
421 process requests from the tlsmgr(8) server in order to seed its
422 internal pseudo random number generator (PRNG).
423 tls_high_cipherlist (ALL:!EXPORT:!LOW:!MEDIUM:+RC4:@STRENGTH)
425 The OpenSSL cipherlist for "HIGH" grade ciphers.
426 tls_medium_cipherlist (ALL:!EXPORT:!LOW:+RC4:@STRENGTH)
428 The OpenSSL cipherlist for "MEDIUM" or higher grade ciphers.
429 tls_low_cipherlist (ALL:!EXPORT:+RC4:@STRENGTH)
431 The OpenSSL cipherlist for "LOW" or higher grade ciphers.
432 tls_export_cipherlist (ALL:+RC4:@STRENGTH)
434 The OpenSSL cipherlist for "EXPORT" or higher grade ciphers.
435 tls_null_cipherlist (eNULL:!aNULL)
437 The OpenSSL cipherlist for "NULL" grade ciphers that provide
438 authentication without encryption.
439 Available in Postfix version 2.4 and later:
441 smtp_sasl_tls_verified_security_options ($smtp_sasl_tls_secu‐
443 rity_options)
444 The SASL authentication security options that the Postfix SMTP
445 client uses for TLS encrypted SMTP sessions with a verified
446 server certificate.
447 Available in Postfix version 2.5 and later:
449 smtp_tls_fingerprint_cert_match (empty)
451 List of acceptable remote SMTP server certificate fingerprints
452 for the "fingerprint" TLS security level (smtp_tls_secu‐
453 rity_level = fingerprint).
454 smtp_tls_fingerprint_digest (md5)
456 The message digest algorithm used to construct remote SMTP
457 server certificate fingerprints.
458 Available in Postfix version 2.6 and later:
460 smtp_tls_protocols (!SSLv2)
462 List of TLS protocols that the Postfix SMTP client will exclude
463 or include with opportunistic TLS encryption.
464 smtp_tls_ciphers (export)
466 The minimum TLS cipher grade that the Postfix SMTP client will
467 use with opportunistic TLS encryption.
468 smtp_tls_eccert_file (empty)
470 File with the Postfix SMTP client ECDSA certificate in PEM for‐
471 mat.
472 smtp_tls_eckey_file ($smtp_tls_eccert_file)
474 File with the Postfix SMTP client ECDSA private key in PEM for‐
475 mat.
476
478 The following configuration parameters exist for compatibility with
479 Postfix versions before 2.3. Support for these will be removed in a
480 future release.
481 smtp_use_tls (no)
483 Opportunistic mode: use TLS when a remote SMTP server announces
484 STARTTLS support, otherwise send the mail in the clear.
485 smtp_enforce_tls (no)
487 Enforcement mode: require that remote SMTP servers use TLS
488 encryption, and never send mail in the clear.
489 smtp_tls_enforce_peername (yes)
491 With mandatory TLS encryption, require that the remote SMTP
492 server hostname matches the information in the remote SMTP
493 server certificate.
494 smtp_tls_per_site (empty)
496 Optional lookup tables with the Postfix SMTP client TLS usage
497 policy by next-hop destination and by remote SMTP server host‐
498 name.
499 smtp_tls_cipherlist (empty)
501 Obsolete Postfix < 2.3 control for the Postfix SMTP client TLS
502 cipher list.
503
505 smtp_destination_concurrency_limit ($default_destination_concur‐
506 rency_limit)
507 The maximal number of parallel deliveries to the same destina‐
508 tion via the smtp message delivery transport.
509 smtp_destination_recipient_limit ($default_destination_recipient_limit)
511 The maximal number of recipients per message for the smtp mes‐
512 sage delivery transport.
513 smtp_connect_timeout (30s)
515 The SMTP client time limit for completing a TCP connection, or
516 zero (use the operating system built-in time limit).
517 smtp_helo_timeout (300s)
519 The SMTP client time limit for sending the HELO or EHLO command,
520 and for receiving the initial server response.
521 lmtp_lhlo_timeout (300s)
523 The LMTP client time limit for sending the LHLO command, and for
524 receiving the initial server response.
525 smtp_xforward_timeout (300s)
527 The SMTP client time limit for sending the XFORWARD command, and
528 for receiving the server response.
529 smtp_mail_timeout (300s)
531 The SMTP client time limit for sending the MAIL FROM command,
532 and for receiving the server response.
533 smtp_rcpt_timeout (300s)
535 The SMTP client time limit for sending the SMTP RCPT TO command,
536 and for receiving the server response.
537 smtp_data_init_timeout (120s)
539 The SMTP client time limit for sending the SMTP DATA command,
540 and for receiving the server response.
541 smtp_data_xfer_timeout (180s)
543 The SMTP client time limit for sending the SMTP message content.
544 smtp_data_done_timeout (600s)
546 The SMTP client time limit for sending the SMTP ".", and for
547 receiving the server response.
548 smtp_quit_timeout (300s)
550 The SMTP client time limit for sending the QUIT command, and for
551 receiving the server response.
552 Available in Postfix version 2.1 and later:
554 smtp_mx_address_limit (5)
556 The maximal number of MX (mail exchanger) IP addresses that can
557 result from mail exchanger lookups, or zero (no limit).
558 smtp_mx_session_limit (2)
560 The maximal number of SMTP sessions per delivery request before
561 giving up or delivering to a fall-back relay host, or zero (no
562 limit).
563 smtp_rset_timeout (20s)
565 The SMTP client time limit for sending the RSET command, and for
566 receiving the server response.
567 Available in Postfix version 2.2 and earlier:
569 lmtp_cache_connection (yes)
571 Keep Postfix LMTP client connections open for up to $max_idle
572 seconds.
573 Available in Postfix version 2.2 and later:
575 smtp_connection_cache_destinations (empty)
577 Permanently enable SMTP connection caching for the specified
578 destinations.
579 smtp_connection_cache_on_demand (yes)
581 Temporarily enable SMTP connection caching while a destination
582 has a high volume of mail in the active queue.
583 smtp_connection_reuse_time_limit (300s)
585 The amount of time during which Postfix will use an SMTP connec‐
586 tion repeatedly.
587 smtp_connection_cache_time_limit (2s)
589 When SMTP connection caching is enabled, the amount of time that
590 an unused SMTP client socket is kept open before it is closed.
591 Available in Postfix version 2.3 and later:
593 connection_cache_protocol_timeout (5s)
595 Time limit for connection cache connect, send or receive opera‐
596 tions.
597
599 debug_peer_level (2)
600 The increment in verbose logging level when a remote client or
601 server matches a pattern in the debug_peer_list parameter.
602 debug_peer_list (empty)
604 Optional list of remote client or server hostname or network
605 address patterns that cause the verbose logging level to
606 increase by the amount specified in $debug_peer_level.
607 error_notice_recipient (postmaster)
609 The recipient of postmaster notifications about mail delivery
610 problems that are caused by policy, resource, software or proto‐
611 col errors.
612 internal_mail_filter_classes (empty)
614 What categories of Postfix-generated mail are subject to before-
615 queue content inspection by non_smtpd_milters, header_checks and
616 body_checks.
617 notify_classes (resource, software)
619 The list of error classes that are reported to the postmaster.
620
622 best_mx_transport (empty)
623 Where the Postfix SMTP client should deliver mail when it
624 detects a "mail loops back to myself" error condition.
625 config_directory (see 'postconf -d' output)
627 The default location of the Postfix main.cf and master.cf con‐
628 figuration files.
629 daemon_timeout (18000s)
631 How much time a Postfix daemon process may take to handle a
632 request before it is terminated by a built-in watchdog timer.
633 delay_logging_resolution_limit (2)
635 The maximal number of digits after the decimal point when log‐
636 ging sub-second delay values.
637 disable_dns_lookups (no)
639 Disable DNS lookups in the Postfix SMTP and LMTP clients.
640 inet_interfaces (all)
642 The network interface addresses that this mail system receives
643 mail on.
644 inet_protocols (ipv4)
646 The Internet protocols Postfix will attempt to use when making
647 or accepting connections.
648 ipc_timeout (3600s)
650 The time limit for sending or receiving information over an
651 internal communication channel.
652 lmtp_assume_final (no)
654 When an LMTP server announces no DSN support, assume that the
655 server performs final delivery, and send "delivered" delivery
656 status notifications instead of "relayed".
657 lmtp_tcp_port (24)
659 The default TCP port that the Postfix LMTP client connects to.
660 max_idle (100s)
662 The maximum amount of time that an idle Postfix daemon process
663 waits for an incoming connection before terminating voluntarily.
664 max_use (100)
666 The maximal number of incoming connections that a Postfix daemon
667 process will service before terminating voluntarily.
668 process_id (read-only)
670 The process ID of a Postfix command or daemon process.
671 process_name (read-only)
673 The process name of a Postfix command or daemon process.
674 proxy_interfaces (empty)
676 The network interface addresses that this mail system receives
677 mail on by way of a proxy or network address translation unit.
678 smtp_bind_address (empty)
680 An optional numerical network address that the Postfix SMTP
681 client should bind to when making an IPv4 connection.
682 smtp_bind_address6 (empty)
684 An optional numerical network address that the Postfix SMTP
685 client should bind to when making an IPv6 connection.
686 smtp_helo_name ($myhostname)
688 The hostname to send in the SMTP EHLO or HELO command.
689 lmtp_lhlo_name ($myhostname)
691 The hostname to send in the LMTP LHLO command.
692 smtp_host_lookup (dns)
694 What mechanisms when the Postfix SMTP client uses to look up a
695 host's IP address.
696 smtp_randomize_addresses (yes)
698 Randomize the order of equal-preference MX host addresses.
699 syslog_facility (mail)
701 The syslog facility of Postfix logging.
702 syslog_name (see 'postconf -d' output)
704 The mail system name that is prepended to the process name in
705 syslog records, so that "smtpd" becomes, for example, "post‐
706 fix/smtpd".
707 Available with Postfix 2.2 and earlier:
709 fallback_relay (empty)
711 Optional list of relay hosts for SMTP destinations that can't be
712 found or that are unreachable.
713 Available with Postfix 2.3 and later:
715 smtp_fallback_relay ($fallback_relay)
717 Optional list of relay hosts for SMTP destinations that can't be
718 found or that are unreachable.
719
721 generic(5), output address rewriting
722 header_checks(5), message header content inspection
723 body_checks(5), body parts content inspection
724 qmgr(8), queue manager
725 bounce(8), delivery status reports
726 scache(8), connection cache server
727 postconf(5), configuration parameters
728 master(5), generic daemon options
729 master(8), process manager
730 tlsmgr(8), TLS session and PRNG management
731 syslogd(8), system logging
732
734 Use "postconf readme_directory" or "postconf html_directory" to locate
735 this information.
736 SASL_README, Postfix SASL howto
737 TLS_README, Postfix STARTTLS howto
738
740 The Secure Mailer license must be distributed with this software.
741
743 Wietse Venema
744 IBM T.J. Watson Research
745 P.O. Box 704
746 Yorktown Heights, NY 10598, USA
747 Command pipelining in cooperation with:
749 Jon Ribbens
750 Oaktree Internet Solutions Ltd.,
751 Internet House,
752 Canal Basin,
753 Coventry,
754 CV1 4LY, United Kingdom.
755 SASL support originally by:
757 Till Franke
758 SuSE Rhein/Main AG
759 65760 Eschborn, Germany
760 TLS support originally by:
762 Lutz Jaenicke
763 BTU Cottbus
764 Allgemeine Elektrotechnik
765 Universitaetsplatz 3-4
766 D-03044 Cottbus, Germany
767 Revised TLS and SMTP connection cache support by:
769 Victor Duchovni
770 Morgan Stanley
771 SMTP(8)