michael@firefly:~$ telnet mailrelay01.virginmedia.co.uk 25
Trying 193.38.119.32...
Connected to mailrelay01.virginmedia.co.uk.
Escape character is '^]'.
220 mailrelay01.telewest.co.uk ESMTP
ehlo mgdm.net
250-mailrelay01.telewest.co.uk
250-8BITMIME
250 SIZE 62914560
mail from:<test@example.org>
250 sender <test@example.org> ok
rcpt to:<eth01@virginmedia.co.uk>
550 #5.1.0 Address rejected eth01@virginmedia.co.uk