Re: AT&T SMTP Admin contact?

[Valdis.Kletnieks () vt edu]

On Tue, 24 Nov 2009 16:38:33 EST, Brad Laue said:

> True, but wouldn't a blacklist of SPF records for known spam issuing
> domains be a more maintainable list than an IP block whitelist?
>
> (I'm no doubt missing something very obvious with this question)

140M+ .com where a malicious DNS server in East Podunk can be authoritative for
a domain actually in Bratslavia and domains are cheap and throw-away.

16M /24's, where you (mostly(*)) need to be able to actually route the packets,
so if you have a /24 in Bratslavia, you need something resembling a router
in Bratslavia as well, and somebody willing to light up the other end of
the cable, and you need a way to make BGP announcements (legal or otherwise ;)
to be able to exploit it.

Choose wisely which you'd rather use for defense.

(*) Mostly - though the BGP hack demonstrated at last year's DefCon
did qualify as an Epic Win for kewl presentations. ;)

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