Re: [Asrg] DNS-based Email Sender Authentication Mechanisms: aCritical Review

["Chris Lewis" <[e-mail]>]

Jose-Marcio Martins da Cruz wrote:

> Well. Me too, I don't understand why it could be interesting to check SPF in the MUA. It 
> may be interesting to check SPF when one have access to both sender domain and IP address 
> of the SMTP client connecting to the MTA. This information isn't usually available to the 
> MUA, unless it will trust on data available on headers.

The Thunderbird SPF/DK plugin, for example, has a configuration option 
that tells it how to parse the Received lines to pluck out the IP and 
HELO recorded in the Received line the user's perimeter MTA has generated.

It works well enough in that regard.

[The plugin isn't compliant with SPF per-se, it checks From:, because it 
usually can't get the MAIL FROM.  This is configurable.]

I experimented with it.  It works.  But doesn't add enough to be worth 
while if you already have decent MTA-end filtering.

If you don't have decent MTA filtering, it might be worthwhile.