SUMMARY OF CHANGES BETWEEN SENDMAIL V5 and V8 The following is a summary of the changes between the last commonly available version of sendmail from Berkeley (5.67) and the latest version (8.1). I can't guarantee that it is complete. Connection Caching Instead of closing SMTP connections immediately, those connections are cached for possible future use. The advent of MX records made this effective for mailing lists; in addition, substantial performance improvements can be expected for queue processing. MX Piggybacking If two hosts with different names in a single message happen to have the same set of MX hosts, they can be sent in the same transaction. Version 8 notices this and tries to batch the messages. RFC 1123 Changes A number of changes have been made to make sendmail ``conditionally compliant'' (that is, it satisfies all of the MUST clauses and most but not all of the SHOULD clauses in RFC 1123). The major areas of change are (numbers are RFC 1123 section numbers): 5.2.7 Response to RCPT command is fast. 5.2.8 Numeric IP addresses are logged in Received: lines. 5.2.17 Self domain literal is properly handled. 5.3.2 Better control over individual timeouts. 5.3.3 Error messages are sent as From:<>. 5.3.3 Error messages are never sent to <>. 5.3.3 Route-addrs are pruned. The areas in which sendmail is not ``unconditionally compliant'' are: 5.2.6 Sendmail does do header munging. 5.2.10 Sendmail doesn't always use the exact SMTP message text from RFC 821. 5.3.1.1 Sendmail doesn't guarantee only one connect for each host on queue runs. 5.3.1.1 Sendmail doesn't always provide an adequate limit on concurrency. Extended SMTP Support Version 8 includes both sending and receiving support for Extended SMTP support as defined by RFC 1425 (basic) and RFC 1427 (SIZE); and limited support for RFC 1426 (BODY). Eight-Bit Clean Previous versions of sendmail used the 0200 bit for quoting. This version avoids that use. However, for compatibility with RFC 822, you can set option `7' to get seven bit stripping. Individual mailers can still produce seven bit out put using the `7' mailer flag. User Database The user database is an as-yet experimental attempt to provide unified large-site name support. We are installing it at Berkeley; future versions may show significant modifications. Improved BIND Support The BIND support, particularly for MX records, had a number of annoying ``features'' which have been removed in this release. In particular, these more tightly bind (pun intended) the name server to sendmail, so that the name server resolution rules are incorporated directly into sendmail. Keyed Files Generalized keyed files is an idea taken directly from IDA sendmail (albeit with a completely different implementation). They can be useful on large sites. Version 8 also understands YP. Multi-Word Classes Classes can now be multiple words. For example, CShofmann.CS.Berkeley.EDU allows you to match the entire string ``hofmann.CS.Berkeley.EDU'' using the single construct ``$=S''. Deferred Macro Expansion The $&x construct has been adopted from IDA . IDENT Protocol Support The IDENT protocol as defined in RFC 1413 is supported. Parsing Bug Fixes A number of small bugs having to do with things like backslash-escaped quotes inside of comments have been fixed. Separate Envelope/Header Processing Since the From: line is passed in separately from the envelope sender, these have both been made visible; the $g macro is set to the envelope sender during processing of mailer argument vectors and the header sender during processing of headers. It is also possible to specify separate per-mailer envelope and header processing. The SenderRWSet and RecipientRWset arguments for mailers can be specified as ``envelope/header'' to give different rewritings for envelope versus header addresses. Owner-List Propagates to Envelope When an alias has an associated owner-list name, that alias is used to change the envelope sender address. This will cause downstream errors to be returned to that owner. Dynamic Header Allocation The fixed size limit on header lines has been eliminated. New Command Line Flags The -B flag has been added to pass in body type information. The -p flag has been added to pass in protocol information. The -X flag has been added to allow logging of all protocol in and out of sendmail for debugging. Enhanced Command Line Flags The -q flag can limit limit a queue run to specific recipients, senders, or queue ids using -qRsubstring, -qSsubstring, or -qIsubstring respectively. New and Old Configuration Line Types The `T' (Trusted users) configuration line has been deleted. It will still be accepted but will be ignored. The `K' line has been added to declare database maps. The `V' line has been added to declare the configuration version level. The `M' (mailer) line takes a D= field to specify execution directory. New Options Several new options have been added, many to support new features, others to allow tuning that was previously available only by recompiling. Briefly: b Insist on a minimum number of disk blocks. C Delivery checkpoint interval. E Default error message. G Enable GECOS matching. h Maximum hop count. j Send errors in MIME-encapsulated format. J Forward file path. k Connection cache size K Connection cache lifetime. l Enable Errors-To: header. These headers violate RFC 1123; this option is included to provide back compatibility with old versions of sendmail. O Incoming daemon options (e.g., use alternate SMTP port). p Privacy options. R Don't prune route-addrs. U User database spec. V Fallback ``MX'' host. 7 Do not run eight bit clean. Extended Options The `r' (read timeout), `I' (use BIND), and `T' (queue timeout) options have been extended to pass in more information. The `A' (alias file) option has been extended to allow multiple alias files of different types. New Mailer Flags a Try to use ESMTP. It will fall back to SMTP if the initial EHLO packet is rejected. b Ensure a blank line at the end of messages. c Strip all comments from addresses; this should only be used as a last resort when dealing with cranky mailers. g Never use the null sender as the envelope sender, even when running SMTP. This violates RFC 1123. 7 Strip all output to this mailer to 7 bits. New Pre-Defined Macros $k UUCP node name from uname(2). $m Domain part of our full hostname. $_ RFC 1413-provided sender address. New LHS Token Version 8 allows `$@' on the Left Hand Side of an `R' line to match zero tokens. This is intended to be used to match the null input. Bigger Defaults Version 8 allows up to 100 rulesets instead of 30. It is recommended that rulesets 0-9 be reserved for sendmail's dedicated use in future releases. The total number of MX records that can be used has been raised to 20. The number of queued messages that can be handled at one time has been raised from 600 to 1000. Different Default Tuning Parameters Version 8 has changed the default parameters for tuning queue costs to make the number of recipients more important than the size of the message (for small messages). This is reasonable if you are connected with reasonably fast links. Auto-Quoting in Addresses Previously, the ``Full Name '' syntax would generate incorrect protocol output if ``Full Name'' had special characters such as dot. This version puts quotes around such names. Symbolic Names On Error Mailer Several names have been built in to the $@ portion of the $#error mailer. SMTP VRFY Doesn't Expand Previous versions of sendmail treated VRFY and EXPN the same. In this version, VRFY doesn't expand aliases or follow .forward files. As an optimization, if you run with your default delivery mode being queue-only, the RCPT command will also not chase aliases and .forward files. It will chase them when it processes the queue. [IPC] Mailers Allow Multiple Hosts When an address resolves to a mailer that has ``[IPC]'' as its ``Path'', the $@ part (host name) can be a colon-separated list of hosts instead of a single hostname. This asks sendmail to search the list for the first entry that is available exactly as though it were an MX record. The intent is to route internal traffic through internal networks without publishing an MX record to the net. MX expansion is still done on the individual items. Aliases Extended The implementation has been merged with maps. Among other things, this supports NIS-based aliases. Portability and Security Enhancements A number of internal changes have been made to enhance portability. Several fixes have been made to increase the paranoia factor. Miscellaneous Enhancements Sendmail writes a /etc/sendmail.pid file with the current process id. Two people using the same program (e.g., submit) are considered "different" so that duplicate elimination doesn't delete one of them. The mailstats program prints mailer names and gets the location of the sendmail.st file from /etc/sendmail.cf. Many minor bugs have been fixed, such as handling of backslashes inside of quotes. A hook has been added to allow rewriting of local addresses after aliasing.