Re: [exim] Exim and SPF

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Autor: Christian Balzer
Data:  
Para: exim-users
Asunto: Re: [exim] Exim and SPF
On Tue, 15 Dec 2009 12:48:54 +0000 Mike Cardwell wrote:

> The example they provide looks dangerous to me:
>
> return_path    = $sender_address_local_part=$local_part=$domain=\
>                     ${hash_8:${hmac{md5}{SECRET}{${lc:\
>                       $sender_address_local_part=$local_part=$domain}}}}\
>                     @$sender_address_domain

>
> Local parts in email addresses have a maximum length of 64 characters,
> yet that could easily expand to something considerably larger than 64
> characters...
>

From the RFC:
To the
maximum extent possible, implementation techniques that impose no
limits on the length of these objects should be used.

Lets just say that I have never seen a rejection/error with this when it
clearly exceeded 64 characters. Which it does much less often than you'd
think.

Basically I picked it because it was simple and did NOT include any time
based data as in BATV. Similar line of reasoning why our greylisting does
not include IP addresses.

YMMV etc.

Christian 
-- 
Christian Balzer        Network/Systems Engineer                
chibi@???       Global OnLine Japan/Fusion Communications
http://www.gol.com/