Dusan Baljevic [email protected] Here is a simple way to test your own SMTP gateway if it allows forged emails to be relayed through it. Let’s pretend to run what a typical attacker would run from their fictive domain anybody.dom (their commands are in bold red). # telnet myhost.blah.dom 25 Trying 22.214.171.124... Connected to myhost.blah.dom. Escape character is '^]'. 220 myhost.blah.dom ESMTP ehlo anybody.dom 250-myhost.blah.dom 250-PIPELINING 250-SIZE 61440000 250-VRFY 250-ETRN 250-STARTTLS 250-ENHANCEDSTATUSCODES 250-8BITMIME 250 DSN MAIL FROM:[email protected] 250 2.1.0 Ok RCPT TO:[email protected] 250 2.1.5 Ok DATA 354 End data with <CR><LF>.<CR><LF> Hello Friend, Did you get this? Attacker . 250 2.0.0 Ok: queued as 64D239EF0014 quit 221 2.0.0 Bye Connection closed by foreign host.