Testing a Suspected Open Relay
If you've identifed a server as being a possible Open Relay, but want to test it to make sure, here is how.
Some system administrators consider a test like this to be Network Abuse. Only test systems that have sent you Spam. Type the following. The server's responses are in italics here, don't type those. The server you are testing should respond similarly.
telnet 210.14.249.124 25
220 some.server.name.com ESMTP Sendmail 8.9.3/8.9.2; Fri, 11 Jan 2002 03:58:30 +0800 (CST)
HELO relaytester
250 some.server.name.com Hello [your_ip_address], pleased to meet you
MAIL FROM: <your_email_address>
250 ok
RCPT TO: <your_email_address>
250 ok
DATA
354 go ahead
To: your_email_address
From: your_email_address
Subject: Relay Test to 210.14.249.124
I received spam from this server. I am testing it to see if it's an Open Relay before
sending complaints.
.
250 ok
QUIT
221 some.server.name.com
Note the final period on a line by itself. That is very important, as it tells the server the message is complete.
If the server is not an Open Relay, it should generate an error after you type the RCPT TO: line. An error will be a 550 code instead of a 250 code. Alternately, the server may accept the message and then send you a bounce instead of delivering the message. If the message is delivered normally to you (after some delay, probably, if this system is currently being abused by spammers especially), then you know for sure it is an Open Relay.
[ Back to Skyway West Knowledge Center ]
[ Back to Spam Resource Page ]
Please send corrections or suggestions for improvements in this page to abuse@skywaywest.com
