SMTP commands

telnet hostname 25

helo <senderdomain>

mail from:

rcpt to:


enter message, complete with to:, from:, and subject: .... finish with a "." on a line by itself


HTTP commands

telnet hostname 80

GET | HEAD [* | /dirname/filename] HTTP/1.0

return, twice.

Nslookup commands

This one is rather useful in determining what machine actually serves as the mail relay for a domain.
Yes, I know that I could do this with dig....but hey, I'm old fashioned that way....


set query=mx | hinfo # MX returns the mail records, hinfo returns the host info record