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Re: Kernel Oops
From: mouss <mouss_at_nospam>Date: Sat Mar 05 2011 - 13:20:52 GMT
To: postfix-users@postfix.org
Le 05/03/2011 00:18, Stan Hoeppner a écrit :
> lst_hoe02@kwsoft.de put forth on 3/4/2011 3:33 PM:
>
>> BTW, is there any "how-to" for getting the least possible memory
>> footprint for Postfix.
>
>> - don't use regex/pcre maps
>
> This isn't necessarily true, is it? In some cases I would think it's
> dramatically reversed in favor of PCRE tables (unless the Postfix PCRE
> processing code overhead eats up a massive amount of memory). For
> example, with the following single PCRE I can block a few million,
> literally, residential hosts in the Centurylink (formerly Embarq)
> consumer broadband aDSL network:
>
> /^.*\.(dyn|dhcp)\.embarqhsd\.net$/ REJECT Please use ISP relay
>
you can simplify that:
/\.(dyn|dhcp)\.embarqhsd\.net$/ REJECT Please use ISP relay
more generally /^.* is never needed.
anyway, this example is too simple and can be replaced with 2 cdb entries:
.dyn.embarqshd.net REJECT ...
.dhcp.embarqshd.net REJECT ...
a "better" example would be
/(\W\d+){4}\..*\.embarqhsd\.net$/ REJECT ...
> To do this with a CIDR would take at least 100 entries to cover all the
> subnets, probably many many more, due to the way they assign blocks by
> state, and rDNS by customer type, with (dyn|dhcp|sta) all existing
> within each of the top level parents.
>
> To do this with a hash table would require multiple hundreds of entries
> as you'd be limited to using /24s.
>