nanog mailing list archives

Re: AT&T SMTP Admin contact?


From: Brad Laue <brad () brad-x com>
Date: Tue, 24 Nov 2009 19:06:42 -0500

On 2009-11-24, at 6:15 PM, Valdis.Kletnieks () vt edu wrote:

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. ;)

Ah, very true. Still really hoping to get in touch with someone from AT&T. :-)

Thanks for the info.


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