[65516] in North American Network Operators' Group
Re: incorrect spam setups cause spool messes on forwarders
daemon@ATHENA.MIT.EDU (Suresh Ramasubramanian)
Mon Dec 1 13:31:53 2003
Date: Mon, 01 Dec 2003 13:30:57 -0500
From: Suresh Ramasubramanian <suresh@outblaze.com>
To: Randy Bush <randy@psg.com>
Cc: nanog@nanog.org
In-Reply-To: <E1AQsVP-0001Oi-MY@ran.psg.com>
Errors-To: owner-nanog-outgoing@merit.edu
Randy Bush writes on 12/1/2003 1:10 PM:
> is the following a general problem, or just one i am seeing?
Verizon does SMTP callbacks, connecting back to the MX of the envelope
sender and trying to verify that the user exists
>
> 2003-12-01 10:09:05 1APbBa-000Ork-DY == foo.user@verizon.net <foo@psg.com> R=lookuphost T=remote_smtp defer (0): SMTP error from remote mailer after MAIL FROM:<nikkiadamczyk@gerbangmail.com> SIZE=5365: host relay.verizon.net [206.46.170.12]: 450 Requested mail action not taken-Try later:sc004pub.verizon.net
>
So this would connect to the MX of gerbangmail.com and try to verify
that whatever@gerbangmail.com exists.
gerbangmail.com. 5h55m6s IN MX 0 sitemail.everyone.net.
If the MX (sitemail.everyone.net) doesn't respond fast enough for
verizon, their tester times out, and the message gets 4xx'd.
srs
--
srs (postmaster|suresh)@outblaze.com // gpg : EDEDEFB9
manager, outblaze.com security and antispam operations
