[CentOS] Recommend Mail Server

Les Mikesell lesmikesell at gmail.com
Tue Nov 24 04:26:00 UTC 2009

Christopher Chan wrote:
> Ian pointed how he needs to 'replicate' a local copy of user 'accounts' 
> from Exchange so that he does not kill Exchange. I just pointed out that 
> this sort of thing can be done also for sites with a very large user 
> base that will want something that is more efficient that Berkeley DB. 

There might be a few places big enough where using cdb vs. the built in bdb for 
the virtuser table would matter.  But very few.

> You can chain lookups in postfix. Check cdb, then check 
> mysql/postgresql. If the account exists in the cdb, then there is no 
> need to check mysql/postgresql. So essentially only non-existent 
> addresses and recently created addresses will result in hits to 
> mysql/postgresql. This is not a work around. This is performance 
> enhancement. Whacking a local cdb will be faster than whacking a 
> mysql/postgresql database. Geez.

If you have a reasonably fast internal mailer you can just let mimedefang on 
your external relay check against it with smtp in real time.  Exchange isn't one 
of those, though.

   Les Mikesell
    lesmikesell at gmail.com

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