Something that I recommend for anyone putting a mail server on the 'net that's open to the public is to telnet to 'relay-test.mail-abuse.org' *FROM* the mail server. The remote host will run a series of tests to see if your system will openly relay for it.
Results from my mail server appear below (note that '206.53.254.241' is my dialup IP address and that 'tnt-206-53-254-241.orl.blueriver.net' is its hostname according to DNS): [jeremy@MERCURY:pts/4:~]$ telnet relay-test.mail-abuse.org Trying 204.152.187.123... Connected to cygnus.mail-abuse.org. Escape character is '^]'. Connecting to 206.53.254.241 ... <<< 220 mercury.main.gaddis.org ESMTP Exim 3.35 #1 Mon, 27 Jan 2003 16:07:28 -0500 >>> HELO cygnus.mail-abuse.org <<< 250 mercury.main.gaddis.org Hello cygnus.mail-abuse.org [204.152.187.123] :Relay test: #Quote test >>> mail from: <[EMAIL PROTECTED]> <<< 250 <[EMAIL PROTECTED]> is syntactically correct >>> rcpt to: <"[EMAIL PROTECTED]"> <<< 501 <"[EMAIL PROTECTED]">: recipient address must contain a domain >>> rset <<< 250 Reset OK :Relay test: #Test 1 >>> mail from: <[EMAIL PROTECTED]> <<< 250 <[EMAIL PROTECTED]> is syntactically correct >>> rcpt to: <[EMAIL PROTECTED]> <<< 550 relaying to <[EMAIL PROTECTED]> prohibited by administrator >>> rset <<< 250 Reset OK :Relay test: #Test 2 >>> mail from: <[EMAIL PROTECTED]> <<< 250 <[EMAIL PROTECTED]> is syntactically correct >>> rcpt to: <[EMAIL PROTECTED]> <<< 550 relaying to <[EMAIL PROTECTED]> prohibited by administrator >>> rset <<< 250 Reset OK :Relay test: #test 3 >>> mail from: <spamtest@localhost> <<< 250 <spamtest@localhost> is syntactically correct >>> rcpt to: <[EMAIL PROTECTED]> <<< 550 relaying to <[EMAIL PROTECTED]> prohibited by administrator >>> rset <<< 250 Reset OK :Relay test: #Test 4 >>> mail from: <spamtest> <<< 501 <spamtest>: sender address must contain a domain >>> rset <<< 250 Reset OK :Relay test: #Test 5 >>> mail from: <> <<< 250 <> is syntactically correct >>> rcpt to: <[EMAIL PROTECTED]> <<< 550 relaying to <[EMAIL PROTECTED]> prohibited by administrator >>> rset <<< 250 Reset OK :Relay test: #Test 6 >>> mail from: <[EMAIL PROTECTED]> <<< 250 <[EMAIL PROTECTED]> is syntactically correct >>> rcpt to: <[EMAIL PROTECTED]> <<< 550 relaying to <[EMAIL PROTECTED]> prohibited by administrator >>> rset <<< 250 Reset OK :Relay test: #Test 7 >>> mail from: <spamtest@[206.53.254.241]> <<< 250 <spamtest@[206.53.254.241]> is syntactically correct >>> rcpt to: <[EMAIL PROTECTED]> <<< 550 relaying to <[EMAIL PROTECTED]> prohibited by administrator >>> rset <<< 250 Reset OK :Relay test: #Test 8 >>> mail from: <[EMAIL PROTECTED]> <<< 250 <[EMAIL PROTECTED]> is syntactically correct >>> rcpt to: <[EMAIL PROTECTED]> <<< 550 relaying to <[EMAIL PROTECTED]> prohibited by administrator >>> rset <<< 250 Reset OK :Relay test: #Test 9 >>> mail from: <[EMAIL PROTECTED]> <<< 250 <[EMAIL PROTECTED]> is syntactically correct >>> rcpt to: <nobody%mail-abuse.org@[206.53.254.241]> <<< 550 relaying to <nobody%mail-abuse.org@[206.53.254.241]> prohibited by administrator >>> rset <<< 250 Reset OK :Relay test: #Test 10 >>> mail from: <[EMAIL PROTECTED]> <<< 250 <[EMAIL PROTECTED]> is syntactically correct >>> rcpt to: <"[EMAIL PROTECTED]"> <<< 501 <"[EMAIL PROTECTED]">: recipient address must contain a domain >>> rset <<< 250 Reset OK :Relay test: #Test 11 >>> mail from: <[EMAIL PROTECTED]> <<< 250 <[EMAIL PROTECTED]> is syntactically correct >>> rcpt to: <"nobody%mail-abuse.org"> <<< 501 <"nobody%mail-abuse.org">: recipient address must contain a domain >>> rset <<< 250 Reset OK :Relay test: #Test 12 >>> mail from: <spamtest@[206.53.254.241]> <<< 250 <spamtest@[206.53.254.241]> is syntactically correct >>> rcpt to: <[EMAIL PROTECTED]@tnt-206-53-254-241.orl.blueriver.net"> <<< 501 <[EMAIL PROTECTED]@tnt-206-53-254-241.orl.blueriver.net">: malformed address: @tnt-206-53-254-241.orl.bluerive may not<<< 501 <[EMAIL PROTECTED]@tnt-206-53-254-241.orl.blueriver.net">: malformed address: @tnt-206-53-254-241.orl.bluerive may not follow <[EMAIL PROTECTED] >>> rset <<< 250 Reset OK :Relay test: #Test 13 >>> mail from: <[EMAIL PROTECTED]> <<< 250 <[EMAIL PROTECTED]> is syntactically correct >>> rcpt to: <"[EMAIL PROTECTED]"@[206.53.254.241]> <<< 550 relaying to <"[EMAIL PROTECTED]"@[206.53.254.241]> prohibited by administrator >>> rset <<< 250 Reset OK :Relay test: #Test 14 >>> mail from: <[EMAIL PROTECTED]> <<< 250 <[EMAIL PROTECTED]> is syntactically correct >>> rcpt to: <[EMAIL PROTECTED]@[206.53.254.241]> <<< 501 <[EMAIL PROTECTED]@[206.53.254.241]>: malformed address: @[206.53.254.241]> may not follow <[EMAIL PROTECTED] >>> rset <<< 250 Reset OK :Relay test: #Test 15 >>> mail from: <spamtest@[206.53.254.241]> <<< 250 <spamtest@[206.53.254.241]> is syntactically correct >>> rcpt to: <@tnt-206-53-254-241.orl.blueriver.net:[EMAIL PROTECTED]> <<< 550 relaying to <[EMAIL PROTECTED]> prohibited by administrator >>> rset <<< 250 Reset OK :Relay test: #Test 16 >>> mail from: <[EMAIL PROTECTED]> <<< 250 <[EMAIL PROTECTED]> is syntactically correct >>> rcpt to: <@[206.53.254.241]:[EMAIL PROTECTED]> <<< 550 relaying to <[EMAIL PROTECTED]> prohibited by administrator >>> rset <<< 250 Reset OK :Relay test: #Test 17 >>> mail from: <spamtest@[206.53.254.241]> <<< 250 <spamtest@[206.53.254.241]> is syntactically correct >>> rcpt to: <mail-abuse.org!nobody> <<< 501 <mail-abuse.org!nobody>: recipient address must contain a domain >>> rset <<< 250 Reset OK :Relay test: #test 18 >>> mail from: <[EMAIL PROTECTED]> <<< 250 <[EMAIL PROTECTED]> is syntactically correct >>> rcpt to: <mail-abuse.org!nobody@[206.53.254.241]> <<< 550 relaying to <mail-abuse.org!nobody@[206.53.254.241]> prohibited by administrator >>> rset <<< 250 Reset OK :Relay test: #test 19 >>> mail from: <[EMAIL PROTECTED]> <<< 250 <[EMAIL PROTECTED]> is syntactically correct >>> rcpt to: <[EMAIL PROTECTED]> <<< 550 relaying to <[EMAIL PROTECTED]> prohibited by administrator >>> rset <<< 250 Reset OK >>> QUIT <<< 221 mercury.main.gaddis.org closing connection Tested host banner: 220 mercury.main.gaddis.org ESMTP Exim 3.35 #1 Mon, 27 Jan 2003 16:07:28 -0500 System appeared to reject relay attempts Connection closed by foreign host. [jeremy@MERCURY:pts/4:~]$ j. -- Jeremy L. Gaddis <[EMAIL PROTECTED]> <http://www.gaddis.org> -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]
