Workshop

• SMTP—Simple Mail Transfer Protocol (server-to-server communication)
• POP—Post Office Protocol (client-to-server communication)
• IMAP—Internet Mail Application Protocol (client-to-server communication)
You can telnet to socket 25 to check whether SMTP gateways are up and accepting connections. Here’s an
example:
$ telnet wpo 25
Trying 167.195.160.7…
Connected to wpo.co.chatham.ga.us.
Escape character is ‘^]’.
220 wpo.co.chatham.ga.us GroupWise SMTP/MIME Daemon 4.11 Ready
1993, 1996 Novell, Inc.
You can also telnet to the POP socket (socket 109 and socket 110, depending on the version of POP that
you’re using) and the IMAP socket (socket 143) to make sure that the servers that are supposed to be
accepting these types of connections are up. Here’s an example:
$ telnet moria 143
Trying 167.195.160.6…
Connected to moria.co.chatham.ga.us.
Escape character is ‘^]’.
* OK moria.co.chatham.ga.us IMAP4rev1 v10.170 server ready
If you’re having trouble getting outside mail from the Internet to your intranet, you’ll want to use nslookup to
check your MX record for your zone. An MX record is a special record denoting the “mail exchanger” for
your zone. Here’s an example:
$ nslookup
> set type=mx
> co.chatham.ga.us
co.chatham.ga.us preference = 10, mail exchanger = moria.co.chatham.ga.us
moria.co.chatham.ga.us internet address = 167.195.160.
If it’s not the right server or if you don’t even have one, you’ll need to change this on your DNS server or ask
your ISP to do it for you.
Dialing Difficulties
Do you run into problems with the following types of dialing?
• Dialing out of your intranet and into the Internet
• Dialing out of your intranet and into somebody else’s intranet