The release of the Exim mail server version 4.95 has taken place, including accumulated fixes and new features. According to a September automated survey of over a million mail servers, Exim holds a 58% share (up from 57.59% last year), Postfix is used on 34.92% (up from 34.70%), Sendmail accounts for 3.52% (down from 3.75%), MailEnable has 2% (down from 2.07%), MDaemon represents 0.57% (down from 0.73%), and Microsoft Exchange stands at 0.32% (down from 0.42%). Main changes:
- Stable support for the fast-ramp message queue processing mode has been announced, allowing for faster message delivery initiation when there is a large outgoing queue and a significant number of messages directed at common hosts, such as when sending a large volume of emails to major mail providers or through a smarthost. If the mode is activated using the 'queue_fast_ramp' option and two-step queue processing ('-qq') detects a substantial batch of messages directed at a specific mail server, server, delivery for that host will begin immediately.
- The alternative implementation of the SRS (Sender Rewriting Scheme) mechanism — 'SRS_NATIVE' — has been stabilized, requiring no external dependencies (the older experimental implementation required the installation of the libsrs_alt library). SRS allows the sender's address to be rewritten upon forwarding without violating SPF (Sender Policy Framework) checks, while preserving sender information for directing proxy server messages in the event of a delivery failure. The essence of the method is that during the establishment of a connection, identity information is passed along with the original sender, for example, rewriting alice@example.org to alice@example.com will include 'SRS0=HHH=TT=example.org=alice@example.com'. SRS is relevant, such as when managing mailing lists where the original message is redirected to other recipients.
- The TLS_RESUME option has been stabilized, enabling the resumption of previously interrupted TLS connections.
- Support for the high-performance, compact embedded database LMDB, which stores data in a key-value format, has been stabilized. Only lookup queries from existing databases by a single key are supported (writing from Exim to LMDB is not implemented). For example, to check a sender's domain in rules, a query such as '${lookup{$sender_address_domain}lmdb{/var/lib/spamdb/stopdomains.mdb}}' can be used.
- The option "message_linelength_limit" has been added to set a limit on the number of characters per line.
- It is now possible to ignore the cache when performing lookup requests.
- For the appendfile transport, a quota check has been implemented during message reception (SMTP session).
- Support for the option "file=" has been added in lookup requests to SQLite, allowing the specification of a database file for a particular operation without using prefixes in the SQL command string.
- Support for the option "ret=full" has been added in lookup requests to Lsearch, enabling the return of the entire data block corresponding to the key instead of just the first row.
- Establishing TLS connections has been accelerated through preloading and caching information (such as certificates) instead of loading it before each connection handling.
- The parameter "proxy_protocol_timeout" has been added to configure the timeout for the Proxy protocol.
- The parameter "smtp_backlog_monitor" has been added to log information about the size of the queue of pending connections (backlog).
- The parameter "hosts_require_helo" has been added, preventing the sending of the MAIL command if the HELO or EHLO command has not been sent earlier.
- The parameter "allow_insecure_tainted_data" has been added, which causes unsafe escaping of special characters in data to output a warning instead of an error.
- Support for the macOS platform has been discontinued (build files have been moved to the unsupported category).
Source: opennet.ru
