Although MX Lookup is not a real term, I like to call an 'nslookup -q=mx' an MX lookup. It is basically looking for the mx records (mail exchange records) for a domain.
If you want to know the names of the mail servers for a domain and the priority level, then you should do an nslookup -q=mx
By all means! It is public knowledge, if you know how to look for it.
This page shows local mail exchanger information. Type the domain name only in the text input below. (i.e. - davidj.org) and then click 'MX Lookup'.
Observe Returns:
Look for preference =#, mail exchanger = server.name.info
Sort Preferences:
The lower number, when there are multiple servers, determines the order that mail will try to send on.
Connect via telnet on port 25:
Telnet to port 25 to see if you can connect, if you can't, you have found your first problem.
Verify SMTP server accepts an email address.
Use smtp commands to send a test message:
If you connect, use mail and rcpt and data commands to send a test message.
mail from:
rcpt to:
data: Type some lines and then put a period by itself on your last line.
quit: To close the connection
Return to the main page.
