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| -rw-r--r-- | RELEASE_NOTES-2.7 | 175 |
1 files changed, 175 insertions, 0 deletions
diff --git a/RELEASE_NOTES-2.7 b/RELEASE_NOTES-2.7 new file mode 100644 index 0000000..8632638 --- /dev/null +++ b/RELEASE_NOTES-2.7 @@ -0,0 +1,175 @@ +The stable Postfix release is called postfix-2.7.x where 2=major +release number, 7=minor release number, x=patchlevel. The stable +release never changes except for patches that address bugs or +emergencies. Patches change the patchlevel and the release date. + +New features are developed in snapshot releases. These are called +postfix-2.8-yyyymmdd where yyyymmdd is the release date (yyyy=year, +mm=month, dd=day). Patches are never issued for snapshot releases; +instead, a new snapshot is released. + +The mail_release_date configuration parameter (format: yyyymmdd) +specifies the release date of a stable release or snapshot release. + +If you upgrade from Postfix 2.5 or earlier, read RELEASE_NOTES-2.6 +before proceeding. + +Major changes - performance +--------------------------- + +[Feature 20100101] Periodic cache cleanup for the verify(8) cache +database. The time between cache cleanup runs is controlled with +the address_verify_cache_cleanup_interval (default: 12h) parameter. +Cache cleanup increases the database access latency, so this should +not be run more often than necessary. + +[Feature 20091109] Improved before-queue filter performance. With +"smtpd_proxy_options = speed_adjust", the Postfix SMTP server +receives the entire message before it connects to a before-queue +content filter. This means you can run more SMTP server processes +with the same number of running content filter processes, and thus, +handle more mail. This feature is off by default until it is proven +to create no new problems. + +This addresses a concern of people in Europe who want to reject all +bad mail with a before-queue filter. The alternative, an after-queue +filter, means they would have to discard bad mail (which is illegal) +or bounce bad mail (which violates good network citizenship). + +NOTE 1: When this feature is turned on, a filter cannot selectively +reject recipients of a multi-recipient message. It is OK to reject +all recipients of the same multi-recipient message, as is deferring +or accepting all recipients of the same multi-recipient message. + +NOTE 2: This feature increases the minimum amount of free queue +space by $message_size_limit. The extra space is needed to save the +message to a temporary file. + +To keep the performance overhead low, the same temporary file is +reused with successive mail transactions (the file is of course +truncated before reuse, so there is no information leakage). + +Major changes - sender reputation +--------------------------------- + +[Feature 20100117] The FILTER action in access maps or header/body_checks +now supports sender reputation schemes that dynamically choose the +SMTP source IP address. Typically, mail is split into classes, and +all mail in class X is sent out from an SMTP client IP address that +is reserved for class X. + +This is implemented by specifying FILTER actions with empty next-hop +destinations in access maps or header/body_checks, and by configuring +in master.cf one Postfix SMTP client for each SMTP source IP address, +where each client has its own "-o myhostname" and "-o smtp_bind_address" +settings. + +[Feature 20091209] sender_dependent_default_transport_maps, a +per-sender override for default_transport. The original motivation +is to use different output channels (with different source IP +addresses) for different sender addresses, in order to keep their +IP-based reputations separate from each other. + +The result value syntax is that of default_transport, not transport_maps. +Thus, sender_dependent_default_transport_maps does not support the +special transport_maps result value syntax for null transport, null +nexthop, or null email address. + +This feature makes sender_dependent_relayhost_maps pretty much +redundant (though sender_dependent_relayhost_maps will often be +easier to use because that is the only thing people want to override). + +Major changes - address verification +------------------------------------ + +[Incompat 20100101] The verify(8) service now uses a persistent +cache by default (address_verify_map = btree:$data_directory/verify_cache). +To disable, specify "address_verify_map =" in main.cf. + +When periodic cache cleanup is enabled (the default), the verify(8) +server now requires that the cache database supports the "delete" +and "sequence" operations. To disable periodic cache cleanup specify +a zero address_verify_cache_cleanup_interval value. + +[Feature 20100101] Periodic cache cleanup for the verify(8) cache +database. The time between cache cleanup runs is controlled with +the address_verify_cache_cleanup_interval (default: 12h) parameter. +Cache cleanup increases the database access latency, so this should +not be run more often than necessary. + +Major changes - content filter +------------------------------ + +[Incompat 20100117] The meaning of an empty filter next-hop destination +has changed (for example, "content_filter = foo:" or "FILTER foo:"). +Postfix now uses the recipient domain, instead of using $myhostname +as in Postfix 2.6 and earlier. To restore the old behavior specify +"default_filter_nexthop = $myhostname", or specify a non-empty +next-hop content filter destination. + +This compatibility option is not needed with SMTP-based content +filters, because these always have an explicit next-hop destination. + +With pipe-based filters that specify no next-hop destination, the +compatibility option restores the FIFO order of deliveries. Without +the compatibility option, the delivery order for filters without +next-hop destination changes to round-robin domain selection. + +[Feature 20100117] The FILTER action in access maps or header/body_checks +now supports sender reputation schemes that dynamically choose the +SMTP source IP address. Typically, mail is split into classes, and +all mail in class X is sent out from an SMTP client IP address that +is reserved for class X. + +This is implemented by specifying FILTER actions with empty next-hop +destinations in access maps or header/body_checks, and by configuring +in master.cf one Postfix SMTP client for each SMTP source IP address, +where each client has its own "-o myhostname" and "-o smtp_bind_address" +settings. + +[Feature 20091109] Improved before-queue filter performance. With +"smtpd_proxy_options = speed_adjust", the Postfix SMTP server +receives the entire message before it connects to a before-queue +content filter. This means you can run more SMTP server processes +with the same number of running content filter processes, and thus, +handle more mail. This feature is off by default until it is proven +to create no new problems. + +This addresses a concern of people in Europe who want to reject all +bad mail with a before-queue filter. The alternative, an after-queue +filter, means they would have to discard bad mail (which is illegal) +or bounce bad mail (which violates good network citizenship). + +NOTE 1: When this feature is turned on, a filter cannot selectively +reject recipients of a multi-recipient message. It is OK to reject +all recipients of the same multi-recipient message, as is deferring +or accepting all recipients of the same multi-recipient message. + +NOTE 2: This feature increases the minimum amount of free queue +space by $message_size_limit. The extra space is needed to save the +message to a temporary file. + +To keep the performance overhead low, the same temporary file is +reused with successive mail transactions (the file is of course +truncated before reuse, so there is no information leakage). + +Major changes - milter +---------------------- + +[Feature 20090606] Support for header checks on Milter-generated +message headers. This can be used, for example, to control mail +flow with Milter-generated headers that carry indicators for badness +or goodness. For details, see the postconf(5) section for +"milter_header_checks". Currently, all header_checks features are +implemented except PREPEND. + +Major changes - multi-instance support +-------------------------------------- + +[Incompat 20090606] The "postmulti -e destroy" command no longer +attempts to remove files that are created AFTER "postmulti -e +create". It still works as expected immediately after creating an +instance by mistake. Trying to automatically remove other files +is too risky because Postfix-owned directories are by design not +trusted. + |