[CentOS] Exim VS Postfix (no flame wars please)

Chan Chung Hang Christopher christopher.chan at bradbury.edu.hk
Tue Mar 9 13:31:08 UTC 2010


Rudi Ahlers wrote:
> Can anyone, who has used both Postfix & Exim please share some experience
> with me? Which of these 2 did you prefer to use, and why?

I have not used exim but I know someone who swears by it. It is highly 
configurable and had stuff like sender based routing before postfix did.


> 
> cPanel uses Exim (and AFAIK, only Exim), VirtualMin seems to use Postfix by
> default and often times when a custom server is installed a client doesn't
> know which to use so we recommend Exim. But, what are the differences
> between these 2, from your experience, if you don't mind telling me?

Exim is monolithic while postfix is not. Next up would be a comparison 
in feature sets (lookup table should be the same - 
mysql,pgsql,ldap,Berkerly DB) but is probably not worth it unless you 
want to do make some really intricate ruleset. The last would probably 
be the difference in behaviour and therefore in tuning. postfix being 
non-monolithic might mean that it has more room for fine-tuning than exim.


> 
> I have used Qmail on FreeBSD 4.8 last and don't even consider this as a good
> mail system anymore, so I'm not even looking at it right now.
> 

qmail on FreeBSD 4.x? Man, FreeBSD 4.x is dog slow. I got a major 
performance boost just be moving from FreeBSD to Redhat Linux back in 
2002/2003 on the same hardware. FreeBSD also only supports directory 
indexing to 1000 entries, anymore than that it will start walking 
through the tree. You do not ever want to build a queue on FreeBSD. 
Anyway, I would not consider using qmail for an mx but I would for an 
outgoing server after it has been patched for smtp-auth support.

The bottom line is, use whatever you are comfortable with or take the 
time to learn the mta's behaviours and features. It won't matter how 
much exim is better than postfix or vice-versa if you are not prepared 
to work with it.


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