Open Relay Test

[Martin P. Hellwig]

D wrote:
> Nope, quite the contrary..I'm looking to write a simple program for a
> client of mine that will, among other things, verify that their
> clients' email servers do not have open relays.
> 
I usually test it like this:

martin at proxy:~> telnet mail.huygenslyceum.nl smtp
Trying 172.16.64.12...
Connected to mail.huygenslyceum.nl.
Escape character is '^]'.
220 mail.huygenslyceum.nl ESMTP Sendmail 8.12.11/8.12.11; Fri, 17 Feb 
2006 10:03:46 +0100 (CET)
~> helo 172.16.64.1
250 mail.huygenslyceum.nl Hello [172.16.64.1], pleased to meet you
~> mail from: mhellwig at xs4all.nl
250 2.1.0 mhellwig at xs4all.nl... Sender ok
~> rcpt to: martin.hellwig at gmail.com
550 5.7.1 martin.hellwig at gmail.com... Relaying denied. IP name lookup 
failed [172.16.64.1]

To get a more verbose explanation, google for smtp + telnet.

hth
-- 
mph