nanog mailing list archives
Re: incorrect spam setups cause spool messes on forwarders
From: Suresh Ramasubramanian <suresh () outblaze com>
Date: Tue, 02 Dec 2003 09:37:06 -0500
Valdis.Kletnieks () vt edu writes on 12/2/2003 9:32 AM:
On Tue, 02 Dec 2003 19:23:41 +0800, Suresh Ramasubramanian <suresh () outblaze com> said:What they are trying to do is to connect back to email.com's MXs and ensure that the user <sgswretyshsdhtest () email com> who is trying to send them mail really does exist, and is not just a figment of some spambot's imagination.And they tell that how, exactly, given that many sites do NOT allow VRFY or EXPN?
MAIL FROM: RCPT TO: QUIT: is precisely what they are doing.Nobody except spammers / dictionary attackers seem to VRFY these days for this sort of stuff. In fact grepping your logs for VRFY is often a reliable sign of a dictionary attack on your machines.
I suppose they could do a MAIL FROM/RCPT TO pair, look at the result, and QUIT instead of DATA. Of course, that would be silly, because if it ever ran into another site that tried the same thing, that site would try to call back and do a MAIL FROM/RCPT TO...
MAIL FROM: <> typically, or from a sender that does not return callbacks to it ... so no danger of loops getting set up. Thank God for small mercies, I guess.
srs -- srs (postmaster|suresh)@outblaze.com // gpg : EDEDEFB9 manager, outblaze.com security and antispam operations
Current thread:
- Re: incorrect spam setups cause spool messes on forwarders, (continued)
- Re: incorrect spam setups cause spool messes on forwarders Michael Lewinski (Dec 01)
- Re: incorrect spam setups cause spool messes on forwarders Daniel Roesen (Dec 01)
- Re: incorrect spam setups cause spool messes on forwarders John Brown (CV) (Dec 02)
- Re: incorrect spam setups cause spool messes on forwarders Daniel Roesen (Dec 02)
- Re: incorrect spam setups cause spool messes on forwarders Randy Bush (Dec 02)
- Re: incorrect spam setups cause spool messes on forwarders Paul Vixie (Dec 02)
- Re: incorrect spam setups cause spool messes on forwarders Daniel Roesen (Dec 01)
- Re: incorrect spam setups cause spool messes on forwarders Michael Lewinski (Dec 01)
- Re: incorrect spam setups cause spool messes on forwarders Valdis . Kletnieks (Dec 02)
- Re: incorrect spam setups cause spool messes on forwarders Suresh Ramasubramanian (Dec 02)
- Re: incorrect spam setups cause spool messes on forwarders Richard Cox (Dec 02)
- Re: incorrect spam setups cause spool messes on forwarders Suresh Ramasubramanian (Dec 02)
- Re: incorrect spam setups cause spool messes on forwarders Valdis . Kletnieks (Dec 02)
- Re: incorrect spam setups cause spool messes on forwarders Suresh Ramasubramanian (Dec 02)