Philip Hazel wrote: > On Fri, 22 Sep 2006, W B Hacker wrote: > > >>A correspondent MTA will not know prior to starting delivery runs that >><domain1>.<tld> and <domain2>.<tld> are hosted on the same virtual server IP, >>so >>will run separate deliveries for the 'To:', 'CC:', Bcc:' not on the same >>domains. > > > Not true for Exim provided that both the virtual servers are using the > same IP address (as you have stated that they are). Independent of the > domains, Exim sorts outgoing addresses according to the host lists they > route to, and uses a single connection for those that are going to the > same hosts (up to the max_rcpt limit, and subject to having the same > added headers, rewritten return-path, etc, etc. that is, when the > message bodies are identical). >
I am sure you are correct about the code, but doubt that conglomeration / batching is even operative unless there is enough near-simultaneous remote_smtp traffic to have accumulate in queue at all. I just tried to simulate that with 'queue_only = true' and Exim invoked with '-q5m'. Three messages pre-composed, sent as fast as I could hit the button, sat in queue for ~ five minutes - as expected, were then sent 1,2,3, - and arrived at the far-end (a Qmail box in ZRH) with different HELO and hostnames - 'generally' appropriate to the sender accounts. There is an element of chance here in that three PTR records are in DNS pointing to the same IP. (Not a practice I recommend anymore, though it has some advantages w/r a *manual* 'host 203.194.153.81' lookup). The 'why' of that may have to do with my router chain, wherein a router per each hosted domain keys on 'From:', for authenticated submissions heading off-box, sets 'helo_data' accordingly before handing-off to the same remote_smtp transport that uses said data. With our 'normal' settings of q55s and queue_only = false, it works under our typical light loads, so I would presume separate IP with single-host per-IP DNS PTR records would be even better separated under light load. A special case load/queue wise? Yes - but not necessarily an uncommon one. "The scientist said that it couldn't be done, but the damn fool Engineer didn't know that, so he did it." J.J. Pershing. ;-) Bill Hacker -- ## List details at http://www.exim.org/mailman/listinfo/exim-users ## Exim details at http://www.exim.org/ ## Please use the Wiki with this list - http://www.exim.org/eximwiki/
