Help wanted with e-mail machine

[Frostmarrow]

Hi! I just thought I'd try to get some help from you guys.

I'm about to retire an old e-mail server (running Unix) and start a new one (Exchange). How do I get e-mail to be delivered to the new machine? Who/what routes e-mail in a LAN with a Windows 2000 Server for DNS and DHCP?

Any help would be welcome.

 

[Rodrigo Istalindir]

The same thing that routes email in a Unix environment (or should be, anyway) -- the MX record in your DNS system (or your ISPs DNS system, if they are hosting DNS for you).

But if it's your only mail server, it's not really routing email internally. You'll just configure your mail client to connect to the Exchange box with the desired protocol (POP3, IMAP, MAPI for Outlook).

Most likely you have your firewall configured to forward SMTP traffic (25) to a specific IP address, so you'll either need to make the Exchange box have the same IP as the retired Unix box, or (better) change the firewalll NAT rule to point to the new IP address of the Exchange server. (And if you're not running the Exchange box behind a firewall, you need to stop doing that now.)

Likely your external DNS A and MX records are already pointing to the public IP referenced in the firewall NAT rule. There should be an A record (eg mail.mydomain.com) and an MX record that points to the name specified in the A record.

If you do have multiple internal mail servers and want to relay email between them, you'll have to add their IP addresses to the SMTP connector in Exchange. By default, Exchange 2000 is not an open relay.

If you have lots of users or lots of email, you may want to seriously consider upgrading to Server2k3/Exchange2k3. Exchange 2000 Standard still has a 16GB limit on total email. 2003 ups that to 75GB.

 

[Frostmarrow]

In my case I have a LAN with a single Unix e-mail server. I have a Netscreen/Firewall-box protecting the LAN.

The thing is, I can't seem to find any entry in the firewall that concerns SMTP or port 25.

If I log onto my Exchange account I can't send or receive e-mail. What happens if I just shut Unix down - will Exchange pick up where Unix left?

 

[Rodrigo Istalindir]

If Exchange isn't sending, its either not configured right or your firewall is blocking outbound port 25 (which is a good thing, as it helps prevent the spread of viruses and spam) from unauthorized servers. Generally, Exchange is ready to send by default, with no additional configuration information necessary, so long as your Windows server is set up properly, especially in regards to DNS.

Things to check:

Is your Unix mail server and/or Exchange server inside or outside your firewall? If inside, you'll need to find the NAT rule that converts your public IP address/name for your mail server to the private IP address on the inside of your network. You'll also need to find the
rule that permits inbound SMTP (25) to that external address.

I gotta go to work (removing an Exchange server, oddly enough). Get back to me on the first thing and I'll post more later.

Also, this should probably be moved to the Computers forum, so if the thread disappears later, look there.

 

[Frostmarrow]

Thanks a bunch! I have found the SMTP-entry in the firewall and I can now switch between the two servers. So that takes care of outgoing mail but how do I get the new Exchange to start receiving incoming mail before the Unix one does?