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Re: [spf-discuss] Current spf record for comcast.net?

2007-01-24 19:28:10
At 08:18 PM 1/24/2007 -0500, Scott wrote:
On Wednesday 24 January 2007 17:43, David MacQuigg wrote:
>
> Comcast is one of the worst for confusing everyone trying to pin down their
> server addresses.  I use their entire IP blocks:
> 24.147.0.0/16        65536
> 63.240.76.0/23         512
> 204.127.0.0/16       65536
> 216.148.227.0-255      256
>          Totals:   4 131840

You might consider building a regexp out of the server names Rene Barbier
provided.

As Guy says, its a never-ending battle.

An IPwhois lookup on 206.18.177.0 shows an allocation of 206.16.0.0/14 by the ARIN Regional Registry. That should cover the addresses shown by Rene and Guy and any others in that block that Comcast might decide to use without notice. If that block includes a few zombies, Comcast's reputation will suffer further. They can fix it by publishing a list of their authorized servers, and excluding the zombies.

The strategy now is to not waste any time arguing with the Comcasts of the world, but simply take whatever they give us, and let their reputation fall where it may. There are plenty of companies like AOL that have an excellent reputation, and it doesn't take much effort to go at least the first step - publish your authorized servers. This should be easy even for a big company that relies on spammers for most of its income. The zombies are not paying customers.

The next step is where it gets interesting. Comcast could use different IDs for different mailflows, allowing the reputation of 'comcast.net' to fall where it may, and using a different ID for their reputable mail. Spammers would then demand that their mail be sent under the reputable ID, and Comcast would have a tough decision. However they try to hide it, the basic deal will involve selling reputation earned by their non-spam customers to people who will quickly ruin that reputation. My guess is Comcast will say no, and the spammers will lose. If they say yes, their non-spam customers will move to another company. What is left won't be worth anything to even the spammers.

> My requirements may be somewhat different than yours, however.  I use this
> list for *whitelisting* not *blacklisting*.  If the IP is within one of
> these ranges, we assume it really is comcast.net, and tag it with a 'B'
> rating.  Recipients who will accept B-rated mail can then receive mail from
> comcast.net with no false rejects.
>...
> Not likely.  They have no real incentive to do so, and the mere mention of
> the word 'spam' will shut down any communication with them.  This will
> change only when they start hearing from their own customers, like
> yourself, that their reputation is hurting their business.  This may happen
> when reputation systems like the one I am working on at open-mail.org,
> become more widely used.

Back when I used Comcast's MTAs, I asked and was unable to find someone I
could talk to that could understand what I was asking for.

The only language they understand is $$$.

-- Dave


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