[afrinic-anti-spam-discuss] Deploying SPF

[Graham Beneke]

Alain Patrick AINA wrote:
>> What happens if you send me mail and on my mail server, I have filters
>> to forward all my mail to another server which does SPF checking. Since
>> the envelope sender did not change, the mail will be rejected at the 2nd
>> server.

Yes - that is a valid concern that is often raised.

> SPF break forwarding and SRS offers a way to fix it.

Sender Rewriting Scheme (SRS) is one solution. The others are to get the 
forwarding server whitelisted on the receiving server or... just don't 
use forwarding ;-)

Personally - the benefits of SPF far outweigh the headaches of 
forwarding. The number of users affected by broken forwarding is 
marginal when compared the number of users getting benefit from SPF.

I know that Gmail already has SRS in their forwarding engine (can't 
comment on any other providers). The MAILFROM is rewritten with the 
original MAILFROM encoded into the local part and then the domain is 
changed to @gmail.com and thus SPF passes on Gmail's record.

Graham

-- 
Graham Beneke
Apolix Internet Services
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