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

Paul Graydon paulgraydon at gmail.com
Tue Mar 9 15:57:42 UTC 2010

Chan Chung Hang Christopher wrote:
> 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've never found it particularly necessary to tune exim, out of the box 
with a basic configuration it handles itself very well and scales nicely 
even up to heavy loads.  I've used it in 100k+ e-mails a day 
environments without any stability or performance problems.  It's a 
rather popular mail server in the UK, possibly by nature of it's origins 
at Cambridge.

I've not spent much time using postfix, but every time I have it's been 
relatively straightforward and intuitive as well.  Always seems to 
perform well too :)

I rather feel its a bit of a case of 6 of one, half a dozen of the 
other.  Both tackle the same problem from slightly different angles, and 
both have achieved excellence in their own ways.

There is a great introduction to configuring exim on this site: 


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