5. DSCP support for outbound connections: on a transport using the smtp driver,
set "dscp = ef", for instance, to cause the connections to have the relevant
- DSCP (IPv4 TOS or IPv6 TCLASS) value in the header. Supported values depend
- upon system libraries. "exim -bI:dscp" to list the ones Exim knows of.
+ DSCP (IPv4 TOS or IPv6 TCLASS) value in the header.
+
+ Similarly for inbound connections, there is a new control modifier, dscp,
+ so "warn control = dscp/ef" in the connect ACL, or after authentication.
+
+ Supported values depend upon system libraries. "exim -bI:dscp" to list the
+ ones Exim knows of. You can also set a raw number 0..0x3F.
+
+ 6. The -G command-line flag is no longer ignored; it is now equivalent to an
+ ACL setting "control = suppress_local_fixups". The -L command-line flag
+ is now accepted and forces use of syslog, with the provided tag as the
+ process name. A few other flags used by Sendmail are now accepted and
+ ignored.
+
+ 7. New cutthrough routing feature. Requested by a "control = cutthrough_delivery"
+ ACL modifier; works for single-recipient mails which are recieved on and
+ deliverable via SMTP. Using the connection made for a recipient verify,
+ if requested before the verify, or a new one made for the purpose while
+ the inbound connection is still active. The bulk of the mail item is copied
+ direct from the inbound socket to the outbound (as well as the spool file).
+ When the source notifies the end of data, the data acceptance by the destination
+ is negociated before the acceptance is sent to the source. If the destination
+ does not accept the mail item, for example due to content-scanning, the item
+ is not accepted from the source and therefore there is no need to generate
+ a bounce mail. This is of benefit when providing a secondary-MX service.
+ The downside is that delays are under the control of the ultimate destination
+ system not your own.
+
+ The Recieved-by: header on items delivered by cutthrough is generated
+ early in of reception rather than at the end; this will affect any timestamp
+ included. The log line showing delivery is recorded before that showing
+ reception; it uses a new ">>" tag instead of "=>".
+
+ To support the feature, verify-callout connections can now use ESMTP and TLS.
+ The usual smtp transport options are honoured, plus a (new, default everything)
+ hosts_verify_avoid_tls.
+
+ New variable families named tls_in_cipher, tls_out_cipher etc. are introduced
+ for specific access to the information for each connection. The old names
+ are present for now but deprecated.
+
+ Not yet supported: IGNOREQUOTA, SIZE, PIPELINING, AUTH.
Version 4.80