Re: [exim] Local senders whitelist: practical limits

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Author: W B Hacker
Date:  
To: exim users
Subject: Re: [exim] Local senders whitelist: practical limits
Rob Munsch wrote:
> Hello list.
>
> Due to increasingly fascist local antispam policies, we are of course
> bouncing a lot of people's mail. Such people are invariably the friends
> and/or business contacts of Important People in the office.
>
> I'm using an
>
>    accept
>      senders = lsearch*@;/etc/exim4/local_whitelist

>
> before my ACLs start getting nasty, which a flat file containing the
> addresses of People Who Should Never Be Blocked. But naturally now that
> the existance of this file is known, everyone wants in on it. One
> enterprising department forwarded me a spreadsheet of 2000 addresses
> "who we never want to get bounces," most of them from @gmail.
>
> So:
>
> 1) How large can this local_whitelist get before i start doing Horrible
> Things to my server's performance?


With most modern CPU, MB, memory, HDD, and file systems, probably well into
tens of thousands of entries. Even then not 'horrible' - just not optimal.

>
> and
>
> 2) Is there a better, more efficient way to call a whitelist other than
> referring to a flat file?


AFAIK, the fastest and least-load is probably one of the variants of a CBD or
TinyDB.

You might have substantial gains by first checking domain-only for as many as
possible, as this will often clear entire companies or even entire 'well
behaved' ISP's with less work.

FWIW, gmail we receive here is pretty clean, though we do pre-check to insure it
is really from gmail, not *forged* gmail.

HTH,

Bill