Changing ISP...quick SMTP question

[BZ079]

We're moving away from our old ISP,

I am looking for conformation before I make any changes, as to what needs to be changed for SMTP.

We have our own Exchange Server, PDC, and Firewall. The new ISP provided us with a new router.

Should it be a matter of swapping out the existing router with the new one, and its setting or is it going to be more complex for SMTP?

SMTP outbound is opened on the firewall through port blah blah, with an address. i.e. 192.168.12.2>172.189.21.2 (not the actual numbers of course) where 172.189.21.2 is our exchange server, is the 192.168.21.2 set externally by our ISP? When a tracetr is done, it comes up Mail.ourname.com Is this something that I need to coordinate with the ISP or is it automatic, or is it part of DNS?


Does anything have to be changed on the exchange server side of things? Im thinking, no, but being a novice I always look for an expert’s opinion.

 

[lhuegele]

If you are changing ISP's, then more than likely your external IP addresses are changing as well. This is not a small deal because you need to make changes to DNS as well as your firewall and the DNS changes could take up to 72 hours to make their way around the entire internet.

Here are some things to remember:

1. The external DNS records for your mail server will need to be changed to point to your new mail server IP address.
2. The SMTP service on your firewall will need to be adjusted to also point the new external IP address to your internal IP address for your server
3. Your new ISP will need to set-up a reverse DNS record for your mail servers new external IP address
4. While none of this should affect outgoing email, incoming email will more than likely be affected.

We use a backup email forwarder for times when we need to take our Exchange server down. That way we don't lose any incoming email. The backup server accepts the incoming email, and then just holds it until our Exchange server is back on line. It then forwards the held emails on to our Exchange server.

Good luck!

 

[BZ079]

Thanks for the info, I completely forgot about the time frame for reverse DNS, As far as incoming mail, it's not a problem as we, like you, have a fowarder, we recently had to do a rebuild on our server due to a system crash, and with the PST files and the new messaged being stored outside we didnt lose anything.



"3. Your new ISP will need to set-up a reverse DNS record for your mail servers new external IP address"

So are you saying that I am going to need multiple external IP's or will 1 do? Again I don't think so, as I may be reading it wrong.

 

[lhuegele]

You only need one external IP address for your server, but since your ISP provides the IP addresses for you, you'll need them to set-up the REVERSE DNS entry for the IP address you assign to your server.

Glad to hear you have a forwarder! I don't know why more people don't use them. They have saved us more than once. <smile>

Good luck!
Larry