Re: [exim] DomainKeys signing makes headers too long -> tagg…

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Author: Ted Cooper
Date:  
To: exim-users
Subject: Re: [exim] DomainKeys signing makes headers too long -> tagged as spam
Tomasz Chmielewski wrote:
> I.e. google/gmail (I've no idea what it uses for signing) creates a
> "wrapped" DomainKey signature.
> So is dkim-proxy I use for signing mail with Postfix.


I guess that means other implementations out there can handle wrapped
lines. I would have been surprised if they didn't but it was/is still
something is double check. I am surprised that exim didn't wrap the
lines when writing the header as it has a specially built print function
that does just that. Something to look at when/if addressing this. I
guess that means it should be added to Bugzilla.

> I think this test is disabled by default in SpamAssassin (at least the
> newest versions).
> But still, I've seen some installations which have it enabled.
>
> Other things SA is giving points to which are also legitimate in email:
> - really lots of recipients
> - ALL CAPS HEADERS
> - mail sent from Windows machines, if you use p0f (passive OS detection
> - most spam senders are Windows zombies)
> - etc.
>
> Single test is usually not enough to tag the message as spam. But it can
> increase the probability that the message is spam.
> If possible, MTA should avoid increasing that probability.


If I was to use any of those rules, the travel agencies I filter emails
for would get nothing. Most of their "legitimate" mail hits every single
one of those rules, and sometimes the entire message is in capital
letters. Needless to say, SA needed considerable tweaking.

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