577 lines
26 KiB
Plaintext
577 lines
26 KiB
Plaintext
In the text below, incompatible changes are labeled with the Postfix
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snapshot that introduced the change. If you upgrade from a later
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Postfix version, then you do not have to worry about that particular
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incompatibility.
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The official Postfix release is called 2.1.x where 2=major release
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number, 1=minor release number, x=patchlevel. Snapshot releases
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are called 2.2-yyyymmdd where yyyymmdd is the release date (yyyy=year,
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mm=month, dd=day). The mail_release_date configuration parameter
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contains the release date (both for official release and snapshot
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release). Patches are issued for the official release and change
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the patchlevel and the release date. Patches are never issued for
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snapshot releases.
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Major changes - critical
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------------------------
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If you run Postfix 2.0 or earlier then you must stop Postfix before
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upgrading. The master-child protocols have changed between Postfix
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1.1 and 2.0, and version 2.1 sometimes writes queue files that the
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2.0 and earlier queue managers complain about. If this happens move
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the files from the corrupt directory to the maildrop directory and
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give them another chance.
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[Incompat 20021119] The Postfix upgrade procedure will add two new
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services to your master.cf file: "trace" and "verify". These servers
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can run inside a chroot jail, have no interaction with users, and
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don't talk to the network. If Postfix complains that "trace" and
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"verify" are not found, you made the error of copying your old
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Postfix configuration files over the new ones. Execute "postfix
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upgrade-configuration" to repair the Postfix configuration files.
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[Incompat 20040331] Support for the non-standard Errors-To: message
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header is removed. This also helps to stop potential attacks that
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rely on bouncing mail to a destination that is not directly reachable
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by the attacker. Specify "enable_errors_to = yes" to get the old
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behavior.
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Queue files written by Postfix 2.1 may contain information that
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is incompatible with older Postfix versions:
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[Incompat 20040120] Queue files creates with "sendmail -v" are no
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longer compatible with Postfix versions 2.0 and earlier. A new
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record type, "killed", was introduced in order to avoid repeated
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mail delivery reports from mail that could not be delivered due to
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a temporary error condition.
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[Incompat 20030125] This release adds a new queue file record type
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for the address specified in "REDIRECT user@domain" actions in
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access maps or header/body_checks. Queue files with these records
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will be rejected by older Postfix versions.
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[Feature 20040120] The new queue manager nqmgr has become the
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default qmgr queue manager. For a limited time the old queue manager
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remains available under the name oqmgr. The name nqmgr still works
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but will cause a warning to be logged.
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[Incompat 20040413] The Postfix SMTP server no longer accepts mail
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from or to an address ending in "@", including address forms that
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rewrite into an address that ends in "@"). Specify "resolve_null_domain
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= yes" to get the old behavior.
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[Incompat 20031226] Postfix no longer allows mail addresses with
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bare numeric IP addresses (user@1.2.3.4). This is not configurable.
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The form user@[ipaddress] is still allowed.
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[Incompat 20031226] Bounce messages now have a separate queue life
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time. This is controlled by the bounce_queue_lifetime parameter.
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Major changes - build environment
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---------------------------------
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[Incompat 20030112] The Postfix build procedure now uses the
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pcre-config utility (part of PCRE version 3) to find out the
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pathnames of the PCRE include file and object library, instead of
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probing /usr/include and/or /usr/lib. To build with PCRE version
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2 support you will have to specify pathnames as described in
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PCRE_README. To build without PCRE support, specify: make Makefiles
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CCARGS="-DNO_PRCE".
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Major changes - documentation
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-----------------------------
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[Feature 20040331] Complete documentation rewrite. All parameters
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are now described in postconf(5), and all commands and daemons are
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shown in their proper context in the OVERVIEW document.
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- All documents come as HTML and ASCII text.
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- All HTML documents have hyperlinks for every parameter name,
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for every Postfix manual page, and for every README file.
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- All documents specify what feature is available in what release.
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- The sample-*.cf configuration files no longer exist. The information
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is now available in HTML documents, README files and UNIX man pages).
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- The mumble_table example configuration files no longer exist.
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[Incompat 20040413] The LMTP, Cyrus and Qmail related README files will
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not be included in the Postfix version 2.1 distribution. They will
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be made available via http://www.postfix.org/, and in Postfix 2.2
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snapshots.
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[Feature 20040413] You can install documentation in HTML format
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besides the README files. Installation of README files is now
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optional.
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Major changes - access control
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------------------------------
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[Feature 20031215] Easier debugging of SMTPD access restrictions.
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The SMTP command "xclient name=xxx addr=yyy" changes Postfix's idea
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of the remote client name and address, so that you can pretend to
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connect from anywhere on the Internet. Use of this command is
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restricted to clients that match the list of names or addresses
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specified with the smtpd_authorized_xclient_hosts parameter. By
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default, XCLIENT is not accepted from anywhere. More details are
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in the XCLIENT_README file.
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[Feature 20030715] Support for multi-valued RBL lookup results.
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For example, specify "reject_rbl_client foo.bar.tld=127.0.0.3" to
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reject clients that are listed with a "127.0.0.3" address record.
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More information is in the postconf(5) manual page.
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[Feature 20030917] New "check_{helo,sender,recipient}_{ns,mx}_access
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type:table" restrictions that apply the specified access table to
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the NS or MX hosts of the host/domain given in HELO, EHLO, MAIL
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FROM or RCPT TO commands. More information is in the postconf(5)
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manual page.
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This can be used to block mail from so-called spammer havens (all
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domains that are served by the same DNS server, all domains that
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resolve to the same MX host), from sender addresses that resolve
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to Verisign's wild-card mail responder, or from domains that claim
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to have mail servers in reserved networks such as 127.0.0.1.
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Note: OK actions are not allowed for security reasons. Instead of
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OK, use DUNNO in order to exclude specific hosts from blacklists.
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If an OK result is found for an NS or MX host, Postfix rejects the
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SMTP command with "451 Server configuration error".
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[Feature 20040413] Support for a "WARN text..." feature in SMTPD
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access tables, just like the WARN feature in header/body_checks.
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[Feature 20040122] New "PREPEND headername: headervalue" action in
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Postfix access maps. Primarily intended for tagging mail by for
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example, an external SMTPD policy server. See access(5).
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[Feature 20040124] New "PREPEND text" action in Postfix header/body_checks
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maps. This action prepends a header or body line immediately before
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the line that triggers the action. See header_checks(5) for details.
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[Feature 20030125] New "REDIRECT user@domain" action for access
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maps and header/body_checks that overrides all the originally
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specified recipients of a message. Wietse would never recommend
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that people use this to redirect (bounced) SPAM to the beneficiaries
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of an advertisement campaign. See access(5) and header_checks(5).
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[Feature 20031215] The reject_sender_login_mismatch feature (used
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with SASL authenticated logins) is now implemented in terms of more
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basic restrictions: reject_unauth_sender_login_mismatch (reject
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mail when $sender_login_maps lists an owner for the sender address
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but the SMTP client is not SASL authenticated) and
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reject_auth_sender_login_mismatch (reject mail when the sender
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address is not owned by the SASL authenticated user). The
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sender_login_maps now support multiple owners per sender address.
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See postconf(5) for details.
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Major changes - address verification
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------------------------------------
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[Feature 20021119] Address verification blocks mail from or to
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addresses that are not deliverable. This is turned on with the
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reject_unverified_sender UCE restriction. Addresses are verified
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by probing, that is, by sending mail that is not actually delivered
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(SMTP interruptus). Detailed information is in the
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ADDRESS_VERIFICATION_README file.
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Address verification can follow a different route than ordinary
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mail, typically to avoid sending probes to a relay host. To make
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this possible, the address resolver supports multiple personalities.
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For more detail see the ADDRESS_VERIFICATION_README file.
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New "sendmail -bv" option. Postfix probes the specified recipient
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addresses without actually delivering mail, and sends back an email
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delivery report. This is useful for testing address rewriting and
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address routing, and shows the final envelope and header addresses.
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This feature currently does not access or update the sender address
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verification database.
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Major changes - content inspection
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----------------------------------
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[Feature 20030704] The Postfix SMTP server can be configured to
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send all mail into a real-time content filter that inspects mail
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BEFORE it is queued. See the SMTPD_PROXY_README file for details.
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[Feature 20031022] Improved logging by Postfix daemons behind an
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SMTP-based proxy filter. The logging now shows the remote client
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name and address, instead of localhost[127.0.0.1]. This uses the
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new SMTP command "XFORWARD addr=client-address name=client-hostname",
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which specifies remote client information for logging purposes.
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This command is restricted to clients that match the list of names
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or addresses specified with the smtpd_authorized_xforward_hosts
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parameter. By default, XFORWARD is not accepted from anywhere.
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For an example, see the SMTPD_PROXY_README file.
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[Feature 20030706] New receive_override_options parameter that
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eliminates the need for different cleanup service instances before
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and after an external content filter. One parameter controls what
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happens before or after the content filter: rejecting unknown
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recipients, canonical mapping, virtual alias expansion, masquerading,
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automatic BCC recipients and header/body checks. See postconf(5)
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for the fine details.
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[Feature 20040124] New "PREPEND text" action in Postfix header/body_checks
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maps. This action prepends a header or body line immediately before
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the line that triggers the action. See header_checks(5) for details.
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[Feature 20030125] New "REDIRECT user@domain" action for access maps
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and header/body_checks that overrides all the originally specified
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recipients of a message. Wietse would never recommend that people
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use this to redirect (bounced) SPAM to the beneficiaries of an
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advertisement campaign. See header_checks(5) and access(5).
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[Incompat 20030915] In header/body_checks actions, the OK action
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is being phased out, and the DUNNO action is being phased in. Both
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actions still work and do the same thing, but hopefully DUNNO causes
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less confusion. See header_checks(5) for details.
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Major changes - policy delegation
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---------------------------------
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[Feature 20030715] Support for SMTP access policy delegation to an
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external server. Greylisting and SPF are provided as examples.
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See the SMTPD_POLICY_README file for further information.
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Major changes - client rate limiting
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------------------------------------
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Note: this feature is not included with Postfix 2.1, but it is
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documented is here so that the information will not be lost.
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[Feature 20031111] Preliminary defense against SMTP clients that
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hammer an SMTP server with too many connections. By default, the
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number of simultaneous connections per client is limited to half
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the default process limit, and no limit is imposed on the number
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of successive connections per time unit that a client is allowed
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to make.
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The new anvil server maintains the connection statistics, and logs
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the maximum connection count and connection rate per client every
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anvil_status_update_time seconds (10 minutes), or when it terminates
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(when there is no work to be done, or when "postfix reload" was
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issued). Once you have an idea what the numbers look like, you can
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clamp down the limits for your system.
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The relevant main.cf configuration parameters are: smtpd_client-
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connection_count_limit for the number of simultaneous connections
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per client, and smtpd_client_connection_rate_limit for the number
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of successive connections per unit time and client. The time unit
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is specified with the anvil_rate_time_unit parameter, and is one
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minute by default.
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When Postfix rejects a client, it sends a 450 status code and
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disconnects, and logs a warning with the client name/address and
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the service name from master.cf. You can, for example, capture this
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information with a logfile watching program that updates a firewall
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rule (such a watcher program is not included with Postfix).
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To avoid rejecting authorized hosts, the smtpd_client_connection-
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limit_exceptions parameter takes a list of network/netmask expressions,
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hostnames or .domain names that are excluded from these restrictions.
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By default, all clients in $mynetworks are excluded; you will
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probably want to use a more restrictive setting.
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For further information, see: smtpd(8) and anvil(8).
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Major changes - configuration management
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----------------------------------------
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[Feature 20040413] New postfix(1) command features:
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- "postfix set-permissions" corrects Postfix file and directory
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permissions and allows you to change mail_owner or setgid_group
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settings after Postfix is installed.
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- "postfix upgrade-configuration" fixes Postfix systems after people
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copy over their old configuration files after installing a new
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Postfix system.
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See postfix(1) for details.
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[Incompat 20040120] The format of the postfix-files file has changed.
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There is a new type for hard links. With hard or symbolic link
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entries, the first field is now the destination pathname and the
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"owner" field is now the origin pathname, while "group" and
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"permissions" are ignored.
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Major changes - core functionality
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----------------------------------
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[Feature 20030704] New enable_original_recipient parameter (default:
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yes) to control whether Postfix keeps track of original recipient
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address information. If this is turned off Postfix produces no
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X-Original-To: headers and ignores the original recipient when
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eliminating duplicates after virtual alias expansion. Code by Victor
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Duchovni.
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[Feature 20030417] Automatic BCC recipients depending on sender or
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recipient address. The configuration parameters in question are
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"sender_bcc_maps" and "recipient_bcc_maps". See postconf(5).
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[Incompat 20030415] Too many people mess up their net/mask patterns,
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causing open mail relay problems. Postfix processes now abort when
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given a net/mask pattern with a non-zero host portion (for example,
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168.100.189.2/28), and suggest to specify the proper net/mask
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pattern instead (for example, 168.100.189.0/28).
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[Feature 20030415] Workaround for file system clock drift that
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caused Postfix to ignore new mail (this could happen with file
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systems mounted from a server). Postfix now logs a warning and
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proceeds with only slightly reduced performance, instead of ignoring
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new mail.
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Major changes - database support
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--------------------------------
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Liviu Daia took the lead in a revision of the LDAP, MySQL and
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PostgreSQL clients. Credits also go to Victor Duchovni and to
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Lamont Jones.
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[Feature 20030915] LDAP parameters can now be defined in external
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files. Specify the LDAP maps in main.cf as
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ldap:/path/to/ldap.cf
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and write the LDAP parameters in /path/to/ldap.cf, without the
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"ldapsource_" prefix. This makes it possible to securely store
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bind passwords for plain auth outside of main.cf (which must be
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world readable). The old syntax still works, for backwards
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compatibility.
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[Feature 20030915] Support for LDAP URLs in the LDAP parameter
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"server_host", if Postfix is linked against OpenLDAP. LDAP hosts,
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ports, and connection protocols to be used as LDAP sources can be
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specified as a blank-separated list of LDAP URLs in "server_host".
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As with OpenLDAP, specifying a port in a LDAP URL overrides
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"server_port". Examples:
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server_host = ldap://ldap.itd.umich.edu
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server_host = ldaps://ldap.itd.umich.edu:636
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server_host = ldapi://%2Fsome%2Fpath
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[Feature 20030915] The LDAP SSL scheme ldaps:// is available if
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OpenLDAP was compiled with SSL support. New parameters "tls_ca_cert_dir",
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"tls_ca_cert_file", "tls_cert", "tls_key", "tls_require_cert",
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"tls_random_file", "tls_cipher_suite" control the certificates,
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source of random numbers, and cipher suites used for SSL connections.
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See LDAP_README for further information.
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[Feature 20030915] Support for STARTTLS command in LDAP, if Postfix
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is linked against OpenLDAP and OpenLDAP was compiled with SSL
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support. STARTTLS is controlled by the "start_tls" parameter.
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The above parameters for certificates, source of random numbers,
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and cipher suites also apply. See LDAP_README for further information.
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[Incompat 20030704] Support for client side LDAP caching is gone.
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OpenLDAP 2.1.13 and later no longer support it, and the feature
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never worked well. Postfix now ignores cache controlling parameters
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in an LDAP configuration file and logs a warning.
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[Feature 20030415] PostgreSQL table lookups. Specify "pgsql:/file/name"
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where "/file/name" defines the database. See "man pgsql_table" for
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examples, and the PGSQL_README file for general information.
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Major changes - internals
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-------------------------
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[Incompat 20040120] The format of the postfix-files file has changed.
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There is a new type for hard links. With hard or symbolic link
|
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entries, the first field is now the destination pathname and the
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"owner" field is now the origin pathname, while "group" and
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"permissions" are ignored.
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[Incompat 20040120] The LDAP and SQL client source code is moved
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to the global directory in order to eliminate reversed dependencies.
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[Feature 20030606] Complete rewrite of the queue file record reading
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loops in the pickup, cleanup and in the queue manager daemons. This
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code had deteriorated over time. The new code eliminates an old
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problem where the queue manager had to read most queue file records
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twice in the case of an alias/include file expansion with more than
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qmgr_message_recipient_limit recipients.
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[Feature 20030125] Code cleanup up of queue manager internals.
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Queue names are no longer mixed up with the next-hop destination,
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and the address resolver loop is now easier to understand.
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[Feature 20030104] Multi-server daemons (servers that accept
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simultaneous connections from multiple clients) will now stop
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accepting new connections after serving $max_use clients. This
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allows multi-server daemons to automatically restart even on busy
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mail systems.
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[Feature 20030104] Clients of multi-server daemons such as
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trivial-rewrite and the new proxymap service now automatically
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disconnect after $ipc_ttl seconds of activity (default: 1000s).
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This allows multi-server daemons to automatically restart even on
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busy mail systems.
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[Incompat 20021119] The file format of bounce/defer logfiles has
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changed from the old one-line ad-hoc format to a more structured
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multi-line format. For backwards compatibility, Postfix now creates
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bounce/defer logfile entries that contain both the old and the new
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format, so that you can go back to an older Postfix release without
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losing information. Old Postfix versions will warn about malformed
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logfile entries, but should work properly. To disable backwards
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compatibility specify "backwards_bounce_logfile_compatibility =
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no" in main.cf.
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[Feature 20021119] Both "sendmail -bv" and "sendmail -v" use the
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new "trace" daemon that is automatically added to master.cf when
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you upgrade.
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Major changes - logging
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-----------------------
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[Incompat 20040413] The postmap and postalias commands now report
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errors to syslogd in addition to reporting them to the standard
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error output. This makes logfile analysis easier.
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[Incompat 20031203] Many SMTPD "reject" logfile entries now show
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NOQUEUE instead of a queue ID. This is because Postfix no longer
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creates a queue file before the SMTP server has received a valid
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recipient.
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Major changes - lookup table support
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------------------------------------
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[Feature 20030704] New CIDR-based lookup table, remotely based on
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code by Jozsef Kadlecsik. For details and examples, see "man
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cidr_table".
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[Feature 20030704] The TCP-based table lookup protocol is finished.
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For details and examples, see "man tcp_table". This will allow you
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to implement your own greylisting, or to do your own open proxy
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tests before accepting mail. This table will not be included with
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Postfix 2.1 because the protocol is obsoleted by the policy delegation
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(see elsewhere in this document) which does a much better job.
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[Feature 20030704] Support for !/pattern/ (negative matches) in
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PCRE lookup tables by Victor Duchovni. See "man pcre_table" and
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"man regexp_table" for more.
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Major changes - resource control
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--------------------------------
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[Incompat 20031022] The Postfix SMTP server no longer accepts mail
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when the amount of free queue space is less than 1.5 times the
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message_size_limit value.
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Major changes - security
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------------------------
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[Incompat 20040413] The Postfix SMTP server no longer accepts mail
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from or to an address ending in "@", including address forms that
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rewrite into an address that ends in "@"). Specify "resolve_null_domain
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= yes" to get the old behavior.
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[Incompat 20040331] Support for the non-standard Errors-To: message
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header is removed. This also helps to stop potential attacks that
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rely on bouncing mail to a destination that is not directly reachable
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by the attacker. Specify ""enable_errors_to = yes" to get the old
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behavior.
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[Incompat 20040331] Tarpit delays are reduced. The Postfix SMTP
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server no longer delays responses until the client has made
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$smtpd_soft_error_limit errors, and the delay is fixed at
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$smtpd_error_sleep_time seconds. Postfix still disconnects after
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$smtpd_hard_error_limit errors.
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[Incompat 20040120] The SMTP server can reject non-existent sender
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addresses in a local, virtual or relay domain; specify
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"reject_unlisted_sender=yes" in order to require that a sender
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address passes the same "user unknown" test as a recipient would
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have to pass. This is optional in Postfix 2.1, likely to be turned
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on by default in Postfix 2.2.
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[Incompat 20031226] Postfix no longer allows mail addresses with
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bare numeric IP addresses (user@1.2.3.4). This is not configurable.
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The form user@[ipaddress] is still allowed.
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[Incompat 20030305] Postfix truncates non-address information in message
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address headers (comments, etc.) to 250 characters per address, in
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order to protect vulnerable Sendmail systems against exploitation
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of a remote buffer overflow problem (CERT advisory CA-2003-07).
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[Incompat 20030227] The smtpd_hard_error_limit and smtpd_soft_error_limit
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values now behave as documented, that is, smtpd_hard_error_limit=1
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causes Postfix to disconnect upon the first client error. Previously,
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there was an off-by-one error causing Postfix to change behavior
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after smtpd_hard/soft_error_limit+1 errors.
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Major changes - smtp client
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---------------------------
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[Incompat 20031223] The SMTP client now tries to connect to an
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alternate MX address when a delivery attempt fails **after the
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initial SMTP handshake**. This includes both broken connections
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and 4XX SMTP replies. To get the old behavior, specify
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"smtp_mx_session_limit = 1" in main.cf.
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[Feature 20031223] The SMTP client now tries to connect to an
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alternate MX address when a delivery attempt fails after the
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initial SMTP handshake. This includes both broken connections
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and 4XX SMTP replies.
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As a benefit, fallback_relay now works as promised, not just for
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sessions that fail during the initial handshake.
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The new SMTP client connection management is controlled by two new
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configuration parameters:
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- smtp_mx_address_limit (default unlimited): the number of MX (mail
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exchanger) IP addresses that can result from mail exchanger
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lookups.
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- smtp_mx_session_limit (default 2): the number of SMTP sessions
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per delivery request before giving up or delivering to a fall-back
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relay, ignoring IP addresses that fail to complete the SMTP
|
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initial handshake.
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[Incompat 20031022] Postfix no longer retries delivery when no MX
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host has a valid A record, for compatibility with many other MTAs.
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This change is made in anticipation of a possible Verisign "wild-card
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MX record without A record" for unregistered domains. To get the
|
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old behavior, specify "smtp_defer_if_no_mx_address_found = yes".
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[Incompat 20031022] The Postfix SMTP client no longer looks in
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/etc/hosts by default. To get the old behavior, specify
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"smtp_host_lookup = dns, native".
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[Feature 20030417] Support for sending mail to hosts not in the
|
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DNS, without having to turn off DNS lookups. The "smtp_host_lookup"
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parameter controls how the Postfix SMTP client looks up hosts. In
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|
order to use /etc/hosts besides DNS, specify "smtp_host_lookup =
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dns, native". The default is to use DNS only.
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|
Major changes - user interface
|
|
------------------------------
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[Incompat 20040418] The non-delivery report format has changed.
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|
The "sorry" message and the DSN formatted report now include the
|
|
original recipient address, when that address is different from
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the final recipient address. This makes it easier to diagnose some
|
|
mail delivery problems that happen after mail forwarding.
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[Incompat 20031223] In mailq (queue listing) output, there no longer
|
|
is space between a short queue ID and the "*" (delivery in progress)
|
|
or ! (mail on hold) status indicator. This makes the output easier
|
|
to parse.
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|
|
[Incompat 20030417] "sendmail -t" no longer complains when recipients
|
|
are given on the command line. Instead, it now adds recipients from
|
|
headers to the recipients from the command-line.
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|
|
[Incompat 20030126] The maildir file naming algorithm has changed
|
|
according to an updated version of http://cr.yp.to/proto/maildir.html.
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|
The name is now TIME.VdevIinum.HOST
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|
[Incompat 20021119] The behavior of "sendmail -v" has changed. One
|
|
-v option now produces one email report with the status of each
|
|
recipient. Multiple -v options behave as before: turn on verbose
|
|
logging in the sendmail and postdrop commands.
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|
[Feature 20021119] New "sendmail -bv" option. Postfix probes the
|
|
specified recipient addresses without actually delivering mail,
|
|
and sends back an email delivery report. This is useful for testing
|
|
address rewriting and address routing of both envelope and header
|
|
addresses. This feature currently does not access or update the
|
|
sender address verification database.
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|