postfix-master/lmtp.8.html

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   7 SMTP(8)                                                                SMTP(8)
   8
   9 <b>NAME</b>
  10        smtp - Postfix SMTP+LMTP client
  11
  12 <b>SYNOPSIS</b>
  13        <b>smtp</b> [generic Postfix daemon options]
  14
  15 <b>DESCRIPTION</b>
  16        The  Postfix SMTP+LMTP client implements the SMTP and LMTP
  17        mail delivery protocols.  It  processes  message  delivery
  18        requests  from the queue manager. Each request specifies a
  19        queue file, a sender address, a domain or host to  deliver
  20        to, and recipient information.  This program expects to be
  21        run from the <a href="master.8.html"><b>master</b>(8)</a> process manager.
  22
  23        The SMTP+LMTP client updates  the  queue  file  and  marks
  24        recipients  as  finished,  or it informs the queue manager
  25        that delivery should be  tried  again  at  a  later  time.
  26        Delivery   status  reports  are  sent  to  the  <a href="bounce.8.html"><b>bounce</b>(8)</a>,
  27        <a href="defer.8.html"><b>defer</b>(8)</a> or <a href="trace.8.html"><b>trace</b>(8)</a> daemon as appropriate.
  28
  29        The SMTP+LMTP client looks up a  list  of  mail  exchanger
  30        addresses  for  the  destination  host,  sorts the list by
  31        preference, and connects to each listed address  until  it
  32        finds a server that responds.
  33
  34        When  a  server  is  not  reachable, or when mail delivery
  35        fails due to a recoverable error condition, the  SMTP+LMTP
  36        client  will try to deliver the mail to an alternate host.
  37
  38        After a successful mail transaction, a connection  may  be
  39        saved to the <a href="scache.8.html"><b>scache</b>(8)</a> connection cache server, so that it
  40        may be used by  any  SMTP+LMTP  client  for  a  subsequent
  41        transaction.
  42
  43        By  default, connection caching is enabled temporarily for
  44        destinations that have a high volume of mail in the active
  45        queue.  Connection  caching can be enabled permanently for
  46        specific destinations.
  47
  48 <b>SMTP DESTINATION SYNTAX</b>
  49        SMTP destinations have the following form:
  50
  51        <i>domainname</i>
  52
  53        <i>domainname</i>:<i>port</i>
  54               Look up  the  mail  exchangers  for  the  specified
  55               domain, and connect to the specified port (default:
  56               <b>smtp</b>).
  57
  58        [<i>hostname</i>]
  59
  60        [<i>hostname</i>]:<i>port</i>
  61               Look up the address(es) of the specified host,  and
  62               connect to the specified port (default: <b>smtp</b>).
  63
  64        [<i>address</i>]
  65
  66        [<i>address</i>]:<i>port</i>
  67               Connect  to  the host at the specified address, and
  68               connect to the specified port (default:  <b>smtp</b>).  An
  69               IPv6 address must be formatted as [<b>ipv6</b>:<i>address</i>].
  70
  71 <b>LMTP DESTINATION SYNTAX</b>
  72        LMTP destinations have the following form:
  73
  74        <b>unix</b>:<i>pathname</i>
  75               Connect  to  the  local  UNIX-domain server that is
  76               bound to the specified  <i>pathname</i>.  If  the  process
  77               runs  chrooted, an absolute pathname is interpreted
  78               relative to the Postfix queue directory.
  79
  80        <b>inet</b>:<i>hostname</i>
  81
  82        <b>inet:</b><i>hostname</i>:<i>port</i>
  83
  84        <b>inet</b>:[<i>address</i>]
  85
  86        <b>inet</b>:[<i>address</i>]:<i>port</i>
  87               Connect to the specified TCP port on the  specified
  88               local or remote host. If no port is specified, con-
  89               nect to the port defined as  <b>lmtp</b>  in  <b>services</b>(4).
  90               If no such service is found, the <b><a href="postconf.5.html#lmtp_tcp_port">lmtp_tcp_port</a></b> con-
  91               figuration parameter (default value of 24) will  be
  92               used.    An  IPv6  address  must  be  formatted  as
  93               [<b>ipv6</b>:<i>address</i>].
  94
  95 <b>SECURITY</b>
  96        The SMTP+LMTP client is moderately security-sensitive.  It
  97        talks  to  SMTP  or LMTP servers and to DNS servers on the
  98        network. The SMTP+LMTP client can be run chrooted at fixed
  99        low privilege.
 100
 101 <b>STANDARDS</b>
 102        <a href="http://tools.ietf.org/html/rfc821">RFC 821</a> (SMTP protocol)
 103        <a href="http://tools.ietf.org/html/rfc822">RFC 822</a> (ARPA Internet Text Messages)
 104        <a href="http://tools.ietf.org/html/rfc1651">RFC 1651</a> (SMTP service extensions)
 105        <a href="http://tools.ietf.org/html/rfc1652">RFC 1652</a> (8bit-MIME transport)
 106        <a href="http://tools.ietf.org/html/rfc1870">RFC 1870</a> (Message Size Declaration)
 107        <a href="http://tools.ietf.org/html/rfc2033">RFC 2033</a> (LMTP protocol)
 108        <a href="http://tools.ietf.org/html/rfc2034">RFC 2034</a> (SMTP Enhanced Error Codes)
 109        <a href="http://tools.ietf.org/html/rfc2045">RFC 2045</a> (MIME: Format of Internet Message Bodies)
 110        <a href="http://tools.ietf.org/html/rfc2046">RFC 2046</a> (MIME: Media Types)
 111        <a href="http://tools.ietf.org/html/rfc2554">RFC 2554</a> (AUTH command)
 112        <a href="http://tools.ietf.org/html/rfc2821">RFC 2821</a> (SMTP protocol)
 113        <a href="http://tools.ietf.org/html/rfc2920">RFC 2920</a> (SMTP Pipelining)
 114        <a href="http://tools.ietf.org/html/rfc3207">RFC 3207</a> (STARTTLS command)
 115        <a href="http://tools.ietf.org/html/rfc3461">RFC 3461</a> (SMTP DSN Extension)
 116        <a href="http://tools.ietf.org/html/rfc3463">RFC 3463</a> (Enhanced Status Codes)
 117        <a href="http://tools.ietf.org/html/rfc4954">RFC 4954</a> (AUTH command)
 118
 119 <b>DIAGNOSTICS</b>
 120        Problems  and transactions are logged to <b>syslogd</b>(8).  Cor-
 121        rupted message files are marked so that the queue  manager
 122        can move them to the <b>corrupt</b> queue for further inspection.
 123
 124        Depending on the setting of the <b><a href="postconf.5.html#notify_classes">notify_classes</a></b>  parameter,
 125        the  postmaster is notified of bounces, protocol problems,
 126        and of other trouble.
 127
 128 <b>BUGS</b>
 129        SMTP and LMTP connection caching does not work  with  TLS.
 130        The  necessary  support for TLS object passivation and re-
 131        activation does not exist  without  closing  the  session,
 132        which defeats the purpose.
 133
 134        SMTP and LMTP connection caching assumes that SASL creden-
 135        tials are valid for all destinations  that  map  onto  the
 136        same IP address and TCP port.
 137
 138 <b>CONFIGURATION PARAMETERS</b>
 139        Before  Postfix version 2.3, the LMTP client is a separate
 140        program that implements only a subset of the functionality
 141        available with SMTP: there is no support for TLS, and con-
 142        nections are cached in-process, making it ineffective when
 143        the client is used for multiple domains.
 144
 145        Most  smtp_<i>xxx</i>  configuration  parameters have an lmtp_<i>xxx</i>
 146        "mirror" parameter for the equivalent LMTP  feature.  This
 147        document describes only those LMTP-related parameters that
 148        aren't simply "mirror" parameters.
 149
 150        Changes to <a href="postconf.5.html"><b>main.cf</b></a> are picked up automatically, as <a href="smtp.8.html"><b>smtp</b>(8)</a>
 151        processes  run  for only a limited amount of time. Use the
 152        command "<b>postfix reload</b>" to speed up a change.
 153
 154        The text below provides  only  a  parameter  summary.  See
 155        <a href="postconf.5.html"><b>postconf</b>(5)</a> for more details including examples.
 156
 157 <b>COMPATIBILITY CONTROLS</b>
 158        <b><a href="postconf.5.html#ignore_mx_lookup_error">ignore_mx_lookup_error</a> (no)</b>
 159               Ignore DNS MX lookups that produce no response.
 160
 161        <b><a href="postconf.5.html#smtp_always_send_ehlo">smtp_always_send_ehlo</a> (yes)</b>
 162               Always send EHLO at the start of an SMTP session.
 163
 164        <b><a href="postconf.5.html#smtp_never_send_ehlo">smtp_never_send_ehlo</a> (no)</b>
 165               Never send EHLO at the start of an SMTP session.
 166
 167        <b><a href="postconf.5.html#smtp_defer_if_no_mx_address_found">smtp_defer_if_no_mx_address_found</a> (no)</b>
 168               Defer  mail  delivery when no MX record resolves to
 169               an IP address.
 170
 171        <b><a href="postconf.5.html#smtp_line_length_limit">smtp_line_length_limit</a> (990)</b>
 172               The maximal length of message header and body lines
 173               that Postfix will send via SMTP.
 174
 175        <b><a href="postconf.5.html#smtp_pix_workaround_delay_time">smtp_pix_workaround_delay_time</a> (10s)</b>
 176               How  long  the  Postfix  SMTP  client pauses before
 177               sending ".&lt;CR&gt;&lt;LF&gt;" in order to work around the PIX
 178               firewall "&lt;CR&gt;&lt;LF&gt;.&lt;CR&gt;&lt;LF&gt;" bug.
 179
 180        <b><a href="postconf.5.html#smtp_pix_workaround_threshold_time">smtp_pix_workaround_threshold_time</a> (500s)</b>
 181               How  long a message must be queued before the Post-
 182               fix  SMTP  client  turns  on   the   PIX   firewall
 183               "&lt;CR&gt;&lt;LF&gt;.&lt;CR&gt;&lt;LF&gt;"  bug  workaround  for  delivery
 184               through firewalls with "smtp fixup" mode turned on.
 185
 186        <b><a href="postconf.5.html#smtp_pix_workarounds">smtp_pix_workarounds</a> (disable_esmtp, delay_dotcrlf)</b>
 187               A  list that specifies zero or more workarounds for
 188               CISCO PIX firewall bugs.
 189
 190        <b><a href="postconf.5.html#smtp_pix_workaround_maps">smtp_pix_workaround_maps</a> (empty)</b>
 191               Lookup tables, indexed by the  remote  SMTP  server
 192               address, with per-destination workarounds for CISCO
 193               PIX firewall bugs.
 194
 195        <b><a href="postconf.5.html#smtp_quote_rfc821_envelope">smtp_quote_rfc821_envelope</a> (yes)</b>
 196               Quote addresses in SMTP MAIL FROM and RCPT TO  com-
 197               mands as required by <a href="http://tools.ietf.org/html/rfc2821">RFC 2821</a>.
 198
 199        <b><a href="postconf.5.html#smtp_reply_filter">smtp_reply_filter</a> (empty)</b>
 200               A  mechanism  to transform replies from remote SMTP
 201               servers one line at a time.
 202
 203        <b><a href="postconf.5.html#smtp_skip_5xx_greeting">smtp_skip_5xx_greeting</a> (yes)</b>
 204               Skip SMTP servers that greet with a 5XX status code
 205               (go away, do not try again later).
 206
 207        <b><a href="postconf.5.html#smtp_skip_quit_response">smtp_skip_quit_response</a> (yes)</b>
 208               Do  not wait for the response to the SMTP QUIT com-
 209               mand.
 210
 211        Available in Postfix version 2.0 and earlier:
 212
 213        <b><a href="postconf.5.html#smtp_skip_4xx_greeting">smtp_skip_4xx_greeting</a> (yes)</b>
 214               Skip SMTP servers that greet with a 4XX status code
 215               (go away, try again later).
 216
 217        Available in Postfix version 2.2 and later:
 218
 219        <b><a href="postconf.5.html#smtp_discard_ehlo_keyword_address_maps">smtp_discard_ehlo_keyword_address_maps</a> (empty)</b>
 220               Lookup  tables,  indexed  by the remote SMTP server
 221               address, with case insensitive lists of  EHLO  key-
 222               words  (pipelining,  starttls, auth, etc.) that the
 223               Postfix  SMTP  client  will  ignore  in  the   EHLO
 224               response from a remote SMTP server.
 225
 226        <b><a href="postconf.5.html#smtp_discard_ehlo_keywords">smtp_discard_ehlo_keywords</a> (empty)</b>
 227               A  case insensitive list of EHLO keywords (pipelin-
 228               ing, starttls, auth, etc.) that  the  Postfix  SMTP
 229               client  will  ignore  in  the  EHLO response from a
 230               remote SMTP server.
 231
 232        <b><a href="postconf.5.html#smtp_generic_maps">smtp_generic_maps</a> (empty)</b>
 233               Optional lookup tables that perform address rewrit-
 234               ing  in  the  SMTP client, typically to transform a
 235               locally valid address into a globally valid address
 236               when sending mail across the Internet.
 237
 238        Available in Postfix version 2.2.9 and later:
 239
 240        <b><a href="postconf.5.html#smtp_cname_overrides_servername">smtp_cname_overrides_servername</a> (version dependent)</b>
 241               Allow  DNS CNAME records to override the servername
 242               that the Postfix SMTP client uses for logging, SASL
 243               password  lookup, TLS policy decisions, or TLS cer-
 244               tificate verification.
 245
 246        Available in Postfix version 2.3 and later:
 247
 248        <b><a href="postconf.5.html#lmtp_discard_lhlo_keyword_address_maps">lmtp_discard_lhlo_keyword_address_maps</a> (empty)</b>
 249               Lookup tables, indexed by the  remote  LMTP  server
 250               address,  with  case insensitive lists of LHLO key-
 251               words (pipelining, starttls, auth, etc.)  that  the
 252               LMTP client will ignore in the LHLO response from a
 253               remote LMTP server.
 254
 255        <b><a href="postconf.5.html#lmtp_discard_lhlo_keywords">lmtp_discard_lhlo_keywords</a> (empty)</b>
 256               A case insensitive list of LHLO keywords  (pipelin-
 257               ing,  starttls,  auth,  etc.)  that the LMTP client
 258               will ignore in the LHLO response from a remote LMTP
 259               server.
 260
 261        Available in Postfix version 2.4.4 and later:
 262
 263        <b><a href="postconf.5.html#send_cyrus_sasl_authzid">send_cyrus_sasl_authzid</a> (no)</b>
 264               When authenticating to a remote SMTP or LMTP server
 265               with the default setting "no", send no SASL  autho-
 266               riZation ID (authzid); send only the SASL authenti-
 267               Cation ID (authcid) plus the authcid's password.
 268
 269        Available in Postfix version 2.5 and later:
 270
 271        <b><a href="postconf.5.html#smtp_header_checks">smtp_header_checks</a> (empty)</b>
 272               Restricted <a href="header_checks.5.html"><b>header_checks</b>(5)</a> tables for the  Postfix
 273               SMTP client.
 274
 275        <b><a href="postconf.5.html#smtp_mime_header_checks">smtp_mime_header_checks</a> (empty)</b>
 276               Restricted  <b><a href="postconf.5.html#mime_header_checks">mime_header_checks</a></b>(5)  tables  for  the
 277               Postfix SMTP client.
 278
 279        <b><a href="postconf.5.html#smtp_nested_header_checks">smtp_nested_header_checks</a> (empty)</b>
 280               Restricted <b><a href="postconf.5.html#nested_header_checks">nested_header_checks</a></b>(5) tables  for  the
 281               Postfix SMTP client.
 282
 283        <b><a href="postconf.5.html#smtp_body_checks">smtp_body_checks</a> (empty)</b>
 284               Restricted  <a href="header_checks.5.html"><b>body_checks</b>(5)</a>  tables  for the Postfix
 285               SMTP client.
 286
 287        Available in Postfix version 2.6 and later:
 288
 289        <b><a href="postconf.5.html#tcp_windowsize">tcp_windowsize</a> (0)</b>
 290               An optional workaround for routers that  break  TCP
 291               window scaling.
 292
 293        Available in Postfix version 2.8 and later:
 294
 295        <b><a href="postconf.5.html#smtp_dns_resolver_options">smtp_dns_resolver_options</a> (empty)</b>
 296               DNS Resolver options for the Postfix SMTP client.
 297
 298        Available in Postfix version 2.9 and later:
 299
 300        <b><a href="postconf.5.html#smtp_per_record_deadline">smtp_per_record_deadline</a> (no)</b>
 301               Change the behavior of the smtp_*_timeout time lim-
 302               its, from a time limit per  read  or  write  system
 303               call,  to  a time limit to read or write a complete
 304               record (an SMTP command line, SMTP  response  line,
 305               SMTP  message  content  line,  or TLS protocol mes-
 306               sage).
 307
 308 <b>MIME PROCESSING CONTROLS</b>
 309        Available in Postfix version 2.0 and later:
 310
 311        <b><a href="postconf.5.html#disable_mime_output_conversion">disable_mime_output_conversion</a> (no)</b>
 312               Disable the conversion of 8BITMIME format  to  7BIT
 313               format.
 314
 315        <b><a href="postconf.5.html#mime_boundary_length_limit">mime_boundary_length_limit</a> (2048)</b>
 316               The  maximal  length  of  MIME  multipart  boundary
 317               strings.
 318
 319        <b><a href="postconf.5.html#mime_nesting_limit">mime_nesting_limit</a> (100)</b>
 320               The maximal recursion level that the MIME processor
 321               will handle.
 322
 323 <b>EXTERNAL CONTENT INSPECTION CONTROLS</b>
 324        Available in Postfix version 2.1 and later:
 325
 326        <b><a href="postconf.5.html#smtp_send_xforward_command">smtp_send_xforward_command</a> (no)</b>
 327               Send  the  non-standard  XFORWARD  command when the
 328               Postfix SMTP server EHLO response  announces  XFOR-
 329               WARD support.
 330
 331 <b>SASL AUTHENTICATION CONTROLS</b>
 332        <b><a href="postconf.5.html#smtp_sasl_auth_enable">smtp_sasl_auth_enable</a> (no)</b>
 333               Enable  SASL  authentication  in  the  Postfix SMTP
 334               client.
 335
 336        <b><a href="postconf.5.html#smtp_sasl_password_maps">smtp_sasl_password_maps</a> (empty)</b>
 337               Optional SMTP client lookup tables with  one  user-
 338               name:password  entry per remote hostname or domain,
 339               or sender address when sender-dependent authentica-
 340               tion is enabled.
 341
 342        <b><a href="postconf.5.html#smtp_sasl_security_options">smtp_sasl_security_options</a> (noplaintext, noanonymous)</b>
 343               Postfix  SMTP  client  SASL security options; as of
 344               Postfix 2.3 the list of available features  depends
 345               on  the SASL client implementation that is selected
 346               with <b><a href="postconf.5.html#smtp_sasl_type">smtp_sasl_type</a></b>.
 347
 348        Available in Postfix version 2.2 and later:
 349
 350        <b><a href="postconf.5.html#smtp_sasl_mechanism_filter">smtp_sasl_mechanism_filter</a> (empty)</b>
 351               If non-empty, a Postfix SMTP client filter for  the
 352               remote  SMTP  server's  list of offered SASL mecha-
 353               nisms.
 354
 355        Available in Postfix version 2.3 and later:
 356
 357        <b><a href="postconf.5.html#smtp_sender_dependent_authentication">smtp_sender_dependent_authentication</a> (no)</b>
 358               Enable sender-dependent authentication in the Post-
 359               fix  SMTP  client; this is available only with SASL
 360               authentication,  and   disables   SMTP   connection
 361               caching  to ensure that mail from different senders
 362               will use the appropriate credentials.
 363
 364        <b><a href="postconf.5.html#smtp_sasl_path">smtp_sasl_path</a> (empty)</b>
 365               Implementation-specific information that the  Post-
 366               fix  SMTP client passes through to the SASL plug-in
 367               implementation    that     is     selected     with
 368               <b><a href="postconf.5.html#smtp_sasl_type">smtp_sasl_type</a></b>.
 369
 370        <b><a href="postconf.5.html#smtp_sasl_type">smtp_sasl_type</a> (cyrus)</b>
 371               The  SASL plug-in type that the Postfix SMTP client
 372               should use for authentication.
 373
 374        Available in Postfix version 2.5 and later:
 375
 376        <b><a href="postconf.5.html#smtp_sasl_auth_cache_name">smtp_sasl_auth_cache_name</a> (empty)</b>
 377               An optional table to prevent repeated SASL  authen-
 378               tication  failures with the same remote SMTP server
 379               hostname, username and password.
 380
 381        <b><a href="postconf.5.html#smtp_sasl_auth_cache_time">smtp_sasl_auth_cache_time</a> (90d)</b>
 382               The maximal  age  of  an  <a href="postconf.5.html#smtp_sasl_auth_cache_name">smtp_sasl_auth_cache_name</a>
 383               entry before it is removed.
 384
 385        <b><a href="postconf.5.html#smtp_sasl_auth_soft_bounce">smtp_sasl_auth_soft_bounce</a> (yes)</b>
 386               When  a remote SMTP server rejects a SASL authenti-
 387               cation request with a 535 reply  code,  defer  mail
 388               delivery  instead  of  returning mail as undeliver-
 389               able.
 390
 391 <b>STARTTLS SUPPORT CONTROLS</b>
 392        Detailed information about STARTTLS configuration  may  be
 393        found in the <a href="TLS_README.html">TLS_README</a> document.
 394
 395        <b><a href="postconf.5.html#smtp_tls_security_level">smtp_tls_security_level</a> (empty)</b>
 396               The default SMTP TLS security level for the Postfix
 397               SMTP client; when a non-empty value  is  specified,
 398               this     overrides    the    obsolete    parameters
 399               <a href="postconf.5.html#smtp_use_tls">smtp_use_tls</a>,         <a href="postconf.5.html#smtp_enforce_tls">smtp_enforce_tls</a>,         and
 400               <a href="postconf.5.html#smtp_tls_enforce_peername">smtp_tls_enforce_peername</a>.
 401
 402        <b><a href="postconf.5.html#smtp_sasl_tls_security_options">smtp_sasl_tls_security_options</a>           ($<a href="postconf.5.html#smtp_sasl_security_options">smtp_sasl_secu</a>-</b>
 403        <b><a href="postconf.5.html#smtp_sasl_security_options">rity_options</a>)</b>
 404               The  SASL  authentication security options that the
 405               Postfix SMTP client uses  for  TLS  encrypted  SMTP
 406               sessions.
 407
 408        <b><a href="postconf.5.html#smtp_starttls_timeout">smtp_starttls_timeout</a> (300s)</b>
 409               Time  limit  for Postfix SMTP client write and read
 410               operations during TLS startup  and  shutdown  hand-
 411               shake procedures.
 412
 413        <b><a href="postconf.5.html#smtp_tls_CAfile">smtp_tls_CAfile</a> (empty)</b>
 414               A  file  containing  CA  certificates  of  root CAs
 415               trusted to sign either remote SMTP server  certifi-
 416               cates or intermediate CA certificates.
 417
 418        <b><a href="postconf.5.html#smtp_tls_CApath">smtp_tls_CApath</a> (empty)</b>
 419               Directory  with  PEM  format  certificate authority
 420               certificates that the Postfix SMTP client  uses  to
 421               verify a remote SMTP server certificate.
 422
 423        <b><a href="postconf.5.html#smtp_tls_cert_file">smtp_tls_cert_file</a> (empty)</b>
 424               File  with  the Postfix SMTP client RSA certificate
 425               in PEM format.
 426
 427        <b><a href="postconf.5.html#smtp_tls_mandatory_ciphers">smtp_tls_mandatory_ciphers</a> (medium)</b>
 428               The minimum TLS cipher grade that the Postfix  SMTP
 429               client will use with mandatory TLS encryption.
 430
 431        <b><a href="postconf.5.html#smtp_tls_exclude_ciphers">smtp_tls_exclude_ciphers</a> (empty)</b>
 432               List of ciphers or cipher types to exclude from the
 433               Postfix SMTP client cipher list at all TLS security
 434               levels.
 435
 436        <b><a href="postconf.5.html#smtp_tls_mandatory_exclude_ciphers">smtp_tls_mandatory_exclude_ciphers</a> (empty)</b>
 437               Additional  list  of  ciphers  or  cipher  types to
 438               exclude from the SMTP client cipher list at  manda-
 439               tory TLS security levels.
 440
 441        <b><a href="postconf.5.html#smtp_tls_dcert_file">smtp_tls_dcert_file</a> (empty)</b>
 442               File  with  the Postfix SMTP client DSA certificate
 443               in PEM format.
 444
 445        <b><a href="postconf.5.html#smtp_tls_dkey_file">smtp_tls_dkey_file</a> ($<a href="postconf.5.html#smtp_tls_dcert_file">smtp_tls_dcert_file</a>)</b>
 446               File with the Postfix SMTP client DSA  private  key
 447               in PEM format.
 448
 449        <b><a href="postconf.5.html#smtp_tls_key_file">smtp_tls_key_file</a> ($<a href="postconf.5.html#smtp_tls_cert_file">smtp_tls_cert_file</a>)</b>
 450               File  with  the Postfix SMTP client RSA private key
 451               in PEM format.
 452
 453        <b><a href="postconf.5.html#smtp_tls_loglevel">smtp_tls_loglevel</a> (0)</b>
 454               Enable additional Postfix SMTP  client  logging  of
 455               TLS activity.
 456
 457        <b><a href="postconf.5.html#smtp_tls_note_starttls_offer">smtp_tls_note_starttls_offer</a> (no)</b>
 458               Log  the  hostname  of  a  remote  SMTP server that
 459               offers STARTTLS, when TLS is  not  already  enabled
 460               for that server.
 461
 462        <b><a href="postconf.5.html#smtp_tls_policy_maps">smtp_tls_policy_maps</a> (empty)</b>
 463               Optional lookup tables with the Postfix SMTP client
 464               TLS security policy by next-hop destination; when a
 465               non-empty  value  is  specified, this overrides the
 466               obsolete <a href="postconf.5.html#smtp_tls_per_site">smtp_tls_per_site</a> parameter.
 467
 468        <b><a href="postconf.5.html#smtp_tls_mandatory_protocols">smtp_tls_mandatory_protocols</a> (SSLv3, TLSv1)</b>
 469               List of SSL/TLS protocols  that  the  Postfix  SMTP
 470               client will use with mandatory TLS encryption.
 471
 472        <b><a href="postconf.5.html#smtp_tls_scert_verifydepth">smtp_tls_scert_verifydepth</a> (9)</b>
 473               The  verification depth for remote SMTP server cer-
 474               tificates.
 475
 476        <b><a href="postconf.5.html#smtp_tls_secure_cert_match">smtp_tls_secure_cert_match</a> (nexthop, dot-nexthop)</b>
 477               The server certificate peername verification method
 478               for the "secure" TLS security level.
 479
 480        <b><a href="postconf.5.html#smtp_tls_session_cache_database">smtp_tls_session_cache_database</a> (empty)</b>
 481               Name  of  the  file containing the optional Postfix
 482               SMTP client TLS session cache.
 483
 484        <b><a href="postconf.5.html#smtp_tls_session_cache_timeout">smtp_tls_session_cache_timeout</a> (3600s)</b>
 485               The expiration time of Postfix SMTP client TLS ses-
 486               sion cache information.
 487
 488        <b><a href="postconf.5.html#smtp_tls_verify_cert_match">smtp_tls_verify_cert_match</a> (hostname)</b>
 489               The server certificate peername verification method
 490               for the "verify" TLS security level.
 491
 492        <b><a href="postconf.5.html#tls_daemon_random_bytes">tls_daemon_random_bytes</a> (32)</b>
 493               The number of pseudo-random bytes that  an  <a href="smtp.8.html"><b>smtp</b>(8)</a>
 494               or  <a href="smtpd.8.html"><b>smtpd</b>(8)</a>  process  requests  from the <a href="tlsmgr.8.html"><b>tlsmgr</b>(8)</a>
 495               server in order to seed its internal pseudo  random
 496               number generator (PRNG).
 497
 498        <b><a href="postconf.5.html#tls_high_cipherlist">tls_high_cipherlist</a></b>
 499        <b>(ALL:!EXPORT:!LOW:!MEDIUM:+RC4:@STRENGTH)</b>
 500               The OpenSSL cipherlist for "HIGH" grade ciphers.
 501
 502        <b><a href="postconf.5.html#tls_medium_cipherlist">tls_medium_cipherlist</a> (ALL:!EXPORT:!LOW:+RC4:@STRENGTH)</b>
 503               The OpenSSL cipherlist for "MEDIUM" or higher grade
 504               ciphers.
 505
 506        <b><a href="postconf.5.html#tls_low_cipherlist">tls_low_cipherlist</a> (ALL:!EXPORT:+RC4:@STRENGTH)</b>
 507               The OpenSSL cipherlist for "LOW"  or  higher  grade
 508               ciphers.
 509
 510        <b><a href="postconf.5.html#tls_export_cipherlist">tls_export_cipherlist</a> (ALL:+RC4:@STRENGTH)</b>
 511               The OpenSSL cipherlist for "EXPORT" or higher grade
 512               ciphers.
 513
 514        <b><a href="postconf.5.html#tls_null_cipherlist">tls_null_cipherlist</a> (eNULL:!aNULL)</b>
 515               The OpenSSL cipherlist  for  "NULL"  grade  ciphers
 516               that provide authentication without encryption.
 517
 518        Available in Postfix version 2.4 and later:
 519
 520        <b><a href="postconf.5.html#smtp_sasl_tls_verified_security_options">smtp_sasl_tls_verified_security_options</a></b>
 521        <b>($<a href="postconf.5.html#smtp_sasl_tls_security_options">smtp_sasl_tls_security_options</a>)</b>
 522               The  SASL  authentication security options that the
 523               Postfix SMTP client uses  for  TLS  encrypted  SMTP
 524               sessions with a verified server certificate.
 525
 526        Available in Postfix version 2.5 and later:
 527
 528        <b><a href="postconf.5.html#smtp_tls_fingerprint_cert_match">smtp_tls_fingerprint_cert_match</a> (empty)</b>
 529               List  of  acceptable remote SMTP server certificate
 530               fingerprints for  the  "fingerprint"  TLS  security
 531               level (<b><a href="postconf.5.html#smtp_tls_security_level">smtp_tls_security_level</a></b> = fingerprint).
 532
 533        <b><a href="postconf.5.html#smtp_tls_fingerprint_digest">smtp_tls_fingerprint_digest</a> (md5)</b>
 534               The  message  digest  algorithm  used  to construct
 535               remote SMTP server certificate fingerprints.
 536
 537        Available in Postfix version 2.6 and later:
 538
 539        <b><a href="postconf.5.html#smtp_tls_protocols">smtp_tls_protocols</a> (!SSLv2)</b>
 540               List of TLS protocols that the Postfix SMTP  client
 541               will  exclude  or  include  with  opportunistic TLS
 542               encryption.
 543
 544        <b><a href="postconf.5.html#smtp_tls_ciphers">smtp_tls_ciphers</a> (export)</b>
 545               The minimum TLS cipher grade that the Postfix  SMTP
 546               client  will use with opportunistic TLS encryption.
 547
 548        <b><a href="postconf.5.html#smtp_tls_eccert_file">smtp_tls_eccert_file</a> (empty)</b>
 549               File with the Postfix SMTP client ECDSA certificate
 550               in PEM format.
 551
 552        <b><a href="postconf.5.html#smtp_tls_eckey_file">smtp_tls_eckey_file</a> ($<a href="postconf.5.html#smtp_tls_eccert_file">smtp_tls_eccert_file</a>)</b>
 553               File with the Postfix SMTP client ECDSA private key
 554               in PEM format.
 555
 556        Available in Postfix version 2.7 and later:
 557
 558        <b><a href="postconf.5.html#smtp_tls_block_early_mail_reply">smtp_tls_block_early_mail_reply</a> (no)</b>
 559               Try to detect a mail hijacking attack  based  on  a
 560               TLS  protocol  vulnerability (CVE-2009-3555), where
 561               an attacker prepends malicious  HELO,  MAIL,  RCPT,
 562               DATA commands to a Postfix SMTP client TLS session.
 563
 564        Available in Postfix version 2.8 and later:
 565
 566        <b><a href="postconf.5.html#tls_disable_workarounds">tls_disable_workarounds</a> (see 'postconf -d' output)</b>
 567               List or bit-mask of  OpenSSL  bug  work-arounds  to
 568               disable.
 569
 570 <b>OBSOLETE STARTTLS CONTROLS</b>
 571        The  following configuration parameters exist for compati-
 572        bility with Postfix versions before 2.3. Support for these
 573        will be removed in a future release.
 574
 575        <b><a href="postconf.5.html#smtp_use_tls">smtp_use_tls</a> (no)</b>
 576               Opportunistic  mode:  use  TLS  when  a remote SMTP
 577               server announces STARTTLS support,  otherwise  send
 578               the mail in the clear.
 579
 580        <b><a href="postconf.5.html#smtp_enforce_tls">smtp_enforce_tls</a> (no)</b>
 581               Enforcement  mode: require that remote SMTP servers
 582               use TLS encryption, and  never  send  mail  in  the
 583               clear.
 584
 585        <b><a href="postconf.5.html#smtp_tls_enforce_peername">smtp_tls_enforce_peername</a> (yes)</b>
 586               With  mandatory  TLS  encryption,  require that the
 587               remote SMTP server hostname matches the information
 588               in the remote SMTP server certificate.
 589
 590        <b><a href="postconf.5.html#smtp_tls_per_site">smtp_tls_per_site</a> (empty)</b>
 591               Optional lookup tables with the Postfix SMTP client
 592               TLS usage policy by  next-hop  destination  and  by
 593               remote SMTP server hostname.
 594
 595        <b><a href="postconf.5.html#smtp_tls_cipherlist">smtp_tls_cipherlist</a> (empty)</b>
 596               Obsolete Postfix &lt; 2.3 control for the Postfix SMTP
 597               client TLS cipher list.
 598
 599 <b>RESOURCE AND RATE CONTROLS</b>
 600        <b><a href="postconf.5.html#smtp_destination_concurrency_limit">smtp_destination_concurrency_limit</a>      ($<a href="postconf.5.html#default_destination_concurrency_limit">default_destina</a>-</b>
 601        <b><a href="postconf.5.html#default_destination_concurrency_limit">tion_concurrency_limit</a>)</b>
 602               The maximal number of parallel  deliveries  to  the
 603               same  destination  via  the  smtp  message delivery
 604               transport.
 605
 606        <b><a href="postconf.5.html#smtp_destination_recipient_limit">smtp_destination_recipient_limit</a>        ($<a href="postconf.5.html#default_destination_recipient_limit">default_destina</a>-</b>
 607        <b><a href="postconf.5.html#default_destination_recipient_limit">tion_recipient_limit</a>)</b>
 608               The maximal number of recipients  per  message  for
 609               the smtp message delivery transport.
 610
 611        <b><a href="postconf.5.html#smtp_connect_timeout">smtp_connect_timeout</a> (30s)</b>
 612               The  SMTP  client  time  limit for completing a TCP
 613               connection,  or  zero  (use  the  operating  system
 614               built-in time limit).
 615
 616        <b><a href="postconf.5.html#smtp_helo_timeout">smtp_helo_timeout</a> (300s)</b>
 617               The  SMTP client time limit for sending the HELO or
 618               EHLO command, and for receiving the initial  server
 619               response.
 620
 621        <b><a href="postconf.5.html#lmtp_lhlo_timeout">lmtp_lhlo_timeout</a> (300s)</b>
 622               The  LMTP  client  time  limit for sending the LHLO
 623               command,  and  for  receiving  the  initial  server
 624               response.
 625
 626        <b><a href="postconf.5.html#smtp_xforward_timeout">smtp_xforward_timeout</a> (300s)</b>
 627               The SMTP client time limit for sending the XFORWARD
 628               command, and for receiving the server response.
 629
 630        <b><a href="postconf.5.html#smtp_mail_timeout">smtp_mail_timeout</a> (300s)</b>
 631               The SMTP client time limit  for  sending  the  MAIL
 632               FROM   command,   and   for  receiving  the  server
 633               response.
 634
 635        <b><a href="postconf.5.html#smtp_rcpt_timeout">smtp_rcpt_timeout</a> (300s)</b>
 636               The SMTP client time limit  for  sending  the  SMTP
 637               RCPT  TO  command,  and  for  receiving  the server
 638               response.
 639
 640        <b><a href="postconf.5.html#smtp_data_init_timeout">smtp_data_init_timeout</a> (120s)</b>
 641               The SMTP client time limit  for  sending  the  SMTP
 642               DATA   command,   and   for  receiving  the  server
 643               response.
 644
 645        <b><a href="postconf.5.html#smtp_data_xfer_timeout">smtp_data_xfer_timeout</a> (180s)</b>
 646               The SMTP client time limit  for  sending  the  SMTP
 647               message content.
 648
 649        <b><a href="postconf.5.html#smtp_data_done_timeout">smtp_data_done_timeout</a> (600s)</b>
 650               The  SMTP  client  time  limit for sending the SMTP
 651               ".", and for receiving the server response.
 652
 653        <b><a href="postconf.5.html#smtp_quit_timeout">smtp_quit_timeout</a> (300s)</b>
 654               The SMTP client time limit  for  sending  the  QUIT
 655               command, and for receiving the server response.
 656
 657        Available in Postfix version 2.1 and later:
 658
 659        <b><a href="postconf.5.html#smtp_mx_address_limit">smtp_mx_address_limit</a> (5)</b>
 660               The  maximal  number  of  MX  (mail  exchanger)  IP
 661               addresses  that  can  result  from  mail  exchanger
 662               lookups, or zero (no limit).
 663
 664        <b><a href="postconf.5.html#smtp_mx_session_limit">smtp_mx_session_limit</a> (2)</b>
 665               The  maximal  number  of SMTP sessions per delivery
 666               request before giving up or delivering to  a  fall-
 667               back <a href="postconf.5.html#relayhost">relay host</a>, or zero (no limit).
 668
 669        <b><a href="postconf.5.html#smtp_rset_timeout">smtp_rset_timeout</a> (20s)</b>
 670               The  SMTP  client  time  limit for sending the RSET
 671               command, and for receiving the server response.
 672
 673        Available in Postfix version 2.2 and earlier:
 674
 675        <b><a href="postconf.5.html#lmtp_cache_connection">lmtp_cache_connection</a> (yes)</b>
 676               Keep Postfix LMTP client connections open for up to
 677               $<a href="postconf.5.html#max_idle">max_idle</a> seconds.
 678
 679        Available in Postfix version 2.2 and later:
 680
 681        <b><a href="postconf.5.html#smtp_connection_cache_destinations">smtp_connection_cache_destinations</a> (empty)</b>
 682               Permanently  enable SMTP connection caching for the
 683               specified destinations.
 684
 685        <b><a href="postconf.5.html#smtp_connection_cache_on_demand">smtp_connection_cache_on_demand</a> (yes)</b>
 686               Temporarily enable SMTP connection caching while  a
 687               destination has a high volume of mail in the active
 688               queue.
 689
 690        <b><a href="postconf.5.html#smtp_connection_reuse_time_limit">smtp_connection_reuse_time_limit</a> (300s)</b>
 691               The amount of time during which Postfix will use an
 692               SMTP connection repeatedly.
 693
 694        <b><a href="postconf.5.html#smtp_connection_cache_time_limit">smtp_connection_cache_time_limit</a> (2s)</b>
 695               When SMTP connection caching is enabled, the amount
 696               of time that an unused SMTP client socket  is  kept
 697               open before it is closed.
 698
 699        Available in Postfix version 2.3 and later:
 700
 701        <b><a href="postconf.5.html#connection_cache_protocol_timeout">connection_cache_protocol_timeout</a> (5s)</b>
 702               Time  limit  for  connection cache connect, send or
 703               receive operations.
 704
 705        Available in Postfix version 2.9 and later:
 706
 707        <b><a href="postconf.5.html#smtp_per_record_deadline">smtp_per_record_deadline</a> (no)</b>
 708               Change the behavior of the smtp_*_timeout time lim-
 709               its,  from  a  time  limit per read or write system
 710               call, to a time limit to read or write  a  complete
 711               record  (an  SMTP command line, SMTP response line,
 712               SMTP message content line,  or  TLS  protocol  mes-
 713               sage).
 714
 715 <b>TROUBLE SHOOTING CONTROLS</b>
 716        <b><a href="postconf.5.html#debug_peer_level">debug_peer_level</a> (2)</b>
 717               The  increment  in  verbose  logging  level  when a
 718               remote client or server matches a  pattern  in  the
 719               <a href="postconf.5.html#debug_peer_list">debug_peer_list</a> parameter.
 720
 721        <b><a href="postconf.5.html#debug_peer_list">debug_peer_list</a> (empty)</b>
 722               Optional  list  of remote client or server hostname
 723               or network address patterns that cause the  verbose
 724               logging  level  to increase by the amount specified
 725               in $<a href="postconf.5.html#debug_peer_level">debug_peer_level</a>.
 726
 727        <b><a href="postconf.5.html#error_notice_recipient">error_notice_recipient</a> (postmaster)</b>
 728               The recipient  of  postmaster  notifications  about
 729               mail  delivery  problems that are caused by policy,
 730               resource, software or protocol errors.
 731
 732        <b><a href="postconf.5.html#internal_mail_filter_classes">internal_mail_filter_classes</a> (empty)</b>
 733               What categories of Postfix-generated mail are  sub-
 734               ject   to   before-queue   content   inspection  by
 735               <a href="postconf.5.html#non_smtpd_milters">non_smtpd_milters</a>, <a href="postconf.5.html#header_checks">header_checks</a> and <a href="postconf.5.html#body_checks">body_checks</a>.
 736
 737        <b><a href="postconf.5.html#notify_classes">notify_classes</a> (resource, software)</b>
 738               The list of error classes that are reported to  the
 739               postmaster.
 740
 741 <b>MISCELLANEOUS CONTROLS</b>
 742        <b><a href="postconf.5.html#best_mx_transport">best_mx_transport</a> (empty)</b>
 743               Where  the  Postfix SMTP client should deliver mail
 744               when it detects a "mail loops back to myself" error
 745               condition.
 746
 747        <b><a href="postconf.5.html#config_directory">config_directory</a> (see 'postconf -d' output)</b>
 748               The  default  location  of  the Postfix <a href="postconf.5.html">main.cf</a> and
 749               <a href="master.5.html">master.cf</a> configuration files.
 750
 751        <b><a href="postconf.5.html#daemon_timeout">daemon_timeout</a> (18000s)</b>
 752               How much time a Postfix daemon process may take  to
 753               handle  a  request  before  it  is  terminated by a
 754               built-in watchdog timer.
 755
 756        <b><a href="postconf.5.html#delay_logging_resolution_limit">delay_logging_resolution_limit</a> (2)</b>
 757               The maximal number  of  digits  after  the  decimal
 758               point when logging sub-second delay values.
 759
 760        <b><a href="postconf.5.html#disable_dns_lookups">disable_dns_lookups</a> (no)</b>
 761               Disable  DNS  lookups  in the Postfix SMTP and LMTP
 762               clients.
 763
 764        <b><a href="postconf.5.html#inet_interfaces">inet_interfaces</a> (all)</b>
 765               The network interface addresses that this mail sys-
 766               tem receives mail on.
 767
 768        <b><a href="postconf.5.html#inet_protocols">inet_protocols</a> (ipv4)</b>
 769               The  Internet protocols Postfix will attempt to use
 770               when making or accepting connections.
 771
 772        <b><a href="postconf.5.html#ipc_timeout">ipc_timeout</a> (3600s)</b>
 773               The time limit for sending or receiving information
 774               over an internal communication channel.
 775
 776        <b><a href="postconf.5.html#lmtp_assume_final">lmtp_assume_final</a> (no)</b>
 777               When  an  LMTP  server  announces  no  DSN support,
 778               assume that the server performs final delivery, and
 779               send   "delivered"  delivery  status  notifications
 780               instead of "relayed".
 781
 782        <b><a href="postconf.5.html#lmtp_tcp_port">lmtp_tcp_port</a> (24)</b>
 783               The default TCP port that the Postfix  LMTP  client
 784               connects to.
 785
 786        <b><a href="postconf.5.html#max_idle">max_idle</a> (100s)</b>
 787               The  maximum  amount  of  time that an idle Postfix
 788               daemon process waits  for  an  incoming  connection
 789               before terminating voluntarily.
 790
 791        <b><a href="postconf.5.html#max_use">max_use</a> (100)</b>
 792               The  maximal  number of incoming connections that a
 793               Postfix daemon process will service  before  termi-
 794               nating voluntarily.
 795
 796        <b><a href="postconf.5.html#process_id">process_id</a> (read-only)</b>
 797               The  process  ID  of  a  Postfix  command or daemon
 798               process.
 799
 800        <b><a href="postconf.5.html#process_name">process_name</a> (read-only)</b>
 801               The process name of a  Postfix  command  or  daemon
 802               process.
 803
 804        <b><a href="postconf.5.html#proxy_interfaces">proxy_interfaces</a> (empty)</b>
 805               The network interface addresses that this mail sys-
 806               tem receives mail on by way of a proxy  or  network
 807               address translation unit.
 808
 809        <b><a href="postconf.5.html#smtp_address_preference">smtp_address_preference</a> (ipv6)</b>
 810               The address type ("ipv6", "ipv4" or "any") that the
 811               Postfix SMTP client will try first, when a destina-
 812               tion  has  IPv6  and  IPv4  addresses with equal MX
 813               preference.
 814
 815        <b><a href="postconf.5.html#smtp_bind_address">smtp_bind_address</a> (empty)</b>
 816               An optional  numerical  network  address  that  the
 817               Postfix  SMTP  client should bind to when making an
 818               IPv4 connection.
 819
 820        <b><a href="postconf.5.html#smtp_bind_address6">smtp_bind_address6</a> (empty)</b>
 821               An optional  numerical  network  address  that  the
 822               Postfix  SMTP  client should bind to when making an
 823               IPv6 connection.
 824
 825        <b><a href="postconf.5.html#smtp_helo_name">smtp_helo_name</a> ($<a href="postconf.5.html#myhostname">myhostname</a>)</b>
 826               The hostname to send in the SMTP EHLO or HELO  com-
 827               mand.
 828
 829        <b><a href="postconf.5.html#lmtp_lhlo_name">lmtp_lhlo_name</a> ($<a href="postconf.5.html#myhostname">myhostname</a>)</b>
 830               The hostname to send in the LMTP LHLO command.
 831
 832        <b><a href="postconf.5.html#smtp_host_lookup">smtp_host_lookup</a> (dns)</b>
 833               What  mechanisms  the  Postfix  SMTP client uses to
 834               look up a host's IP address.
 835
 836        <b><a href="postconf.5.html#smtp_randomize_addresses">smtp_randomize_addresses</a> (yes)</b>
 837               Randomize the order  of  equal-preference  MX  host
 838               addresses.
 839
 840        <b><a href="postconf.5.html#syslog_facility">syslog_facility</a> (mail)</b>
 841               The syslog facility of Postfix logging.
 842
 843        <b><a href="postconf.5.html#syslog_name">syslog_name</a> (see 'postconf -d' output)</b>
 844               The  mail  system  name  that  is  prepended to the
 845               process name in syslog  records,  so  that  "smtpd"
 846               becomes, for example, "postfix/smtpd".
 847
 848        Available with Postfix 2.2 and earlier:
 849
 850        <b><a href="postconf.5.html#fallback_relay">fallback_relay</a> (empty)</b>
 851               Optional  list of relay hosts for SMTP destinations
 852               that can't be found or that are unreachable.
 853
 854        Available with Postfix 2.3 and later:
 855
 856        <b><a href="postconf.5.html#smtp_fallback_relay">smtp_fallback_relay</a> ($<a href="postconf.5.html#fallback_relay">fallback_relay</a>)</b>
 857               Optional list of relay hosts for SMTP  destinations
 858               that can't be found or that are unreachable.
 859
 860 <b>SEE ALSO</b>
 861        <a href="generic.5.html">generic(5)</a>, output address rewriting
 862        <a href="header_checks.5.html">header_checks(5)</a>, message header content inspection
 863        <a href="header_checks.5.html">body_checks(5)</a>, body parts content inspection
 864        <a href="qmgr.8.html">qmgr(8)</a>, queue manager
 865        <a href="bounce.8.html">bounce(8)</a>, delivery status reports
 866        <a href="scache.8.html">scache(8)</a>, connection cache server
 867        <a href="postconf.5.html">postconf(5)</a>, configuration parameters
 868        <a href="master.5.html">master(5)</a>, generic daemon options
 869        <a href="master.8.html">master(8)</a>, process manager
 870        <a href="tlsmgr.8.html">tlsmgr(8)</a>, TLS session and PRNG management
 871        syslogd(8), system logging
 872
 873 <b>README FILES</b>
 874        <a href="SASL_README.html">SASL_README</a>, Postfix SASL howto
 875        <a href="TLS_README.html">TLS_README</a>, Postfix STARTTLS howto
 876
 877 <b>LICENSE</b>
 878        The Secure Mailer license must be  distributed  with  this
 879        software.
 880
 881 <b>AUTHOR(S)</b>
 882        Wietse Venema
 883        IBM T.J. Watson Research
 884        P.O. Box 704
 885        Yorktown Heights, NY 10598, USA
 886
 887        Command pipelining in cooperation with:
 888        Jon Ribbens
 889        Oaktree Internet Solutions Ltd.,
 890        Internet House,
 891        Canal Basin,
 892        Coventry,
 893        CV1 4LY, United Kingdom.
 894
 895        SASL support originally by:
 896        Till Franke
 897        SuSE Rhein/Main AG
 898        65760 Eschborn, Germany
 899
 900        TLS support originally by:
 901        Lutz Jaenicke
 902        BTU Cottbus
 903        Allgemeine Elektrotechnik
 904        Universitaetsplatz 3-4
 905        D-03044 Cottbus, Germany
 906
 907        Revised TLS and SMTP connection cache support by:
 908        Victor Duchovni
 909        Morgan Stanley
 910
 911                                                                        SMTP(8)
 912 </pre> </body> </html>