The recently published release of the mail server Exim 4.99 has brought a host of accumulated fixes and added new features. Exim is a project written in C and distributed under the GPLv2+ license. According to an automated survey of about 500 thousand mail servers, Exim holds a share of 56%, down from 59.06% a year ago. Postfix is used on 37.45% of servers (up from 34.68%), Sendmail on 3.53% (up from 3.42%), MailEnable on 1.84% (up from 1.81%), MDaemon on 0.40% (up from 0.37%), and Microsoft Exchange on 0.20% (up from 0.17%).
Some of the main changes in this release include:
- Added support for the ESMTP command “ATRN” (Authenticated TURN), allowing the server and client roles to be changed during message delivery. This feature is useful for systems with dynamic IP addresses or inconsistent internet access, enabling the client to act as a server to receive backlogged messages. The command requires successful authentication and a permissive ACL (acl_smtp_atrn).
- Most Exim components can now be compiled as loadable modules, such as JSON and LDAP lookup engines, filters, authentication and routing drivers, PAM, RADIUS, perl, SPF, DKIM, DMARC, ARC components, and non-SMTP transport types.
- Option to disable Exim and Sieve filters at the build stage.
- Added support for DNS records SRV (Service Location Record) to determine recipient mail servers’ TLS support.
- Experimental build option “EXPERIMENTAL_SPF_PERL” offers an alternative SPF authentication mechanism using the Perl module Mail::SPF instead of libspf2.
- Experimental build option “EXPERIMENTAL_NMH” integrates a lookup engine for checking IP addresses in the NMH (Net-Masked Hero) storage.
- Configuration file now includes the “tls_early_banner_hosts” setting to specify hosts for applying the “TLS Early Data” mechanism.
/Reports, release notes, official announcements.