Hi Heiko, On Wed, 16 Jun 2010, Heiko Schlittermann wrote:
>>> Does exim use the Backup MX if the primary MX is available? Can I >>> configure exim to prefer the primary MX? >> >> Exim should try the primary first, as any MTA should. Sometimes it may >> fail to reach the primary, and fall back to the secondary, particularly >> if the primary uses greylisting. The secondary is tempfailing the mail, >> because *it* thinks the primary is still up, which causes exim to try >> the primary again later. Seems fairly normal and OK to me. > > But it's quite stupid by second mx, to think that my (network) > connectivity to the second mx is the same as to the first mx. Maybe, or maybe it just hasn't noticed yet. I implemented a trick with exim to do exactly this, to ensure that the backup MX does not accept mail when the primary is still up, to reduce the backup MX spam problem: http://blog.aptivate.org/2009/01/28/backup-mail-exchangers/ I reduced the callout positive cache expiry time to five minutes, but still during that time, the backup MX will think that the primary is still up. I think that it doesn't do any harm except to slightly delay mail being accepted by the backup when the primary is down. Cheers, Chris. -- _ ___ __ _ / __/ / ,__(_)_ | Chris Wilson <0000 at qwirx.com> - Cambs UK | / (_/ ,\/ _/ /_ \ | Security/C/C++/Java/Perl/SQL/HTML Developer | \ _/_/_/_//_/___/ | We are GNU-free your mind-and your software | -- ## List details at http://lists.exim.org/mailman/listinfo/exim-users ## Exim details at http://www.exim.org/ ## Please use the Wiki with this list - http://wiki.exim.org/
