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Exchange - Changing external static I.P, what needs to be done?

Posted on 2014-12-31
Medium Priority
Last Modified: 2015-01-08
After an office move we have been dealt a new external i.p address

Our main server was receiving email fine before the move - I understand that we need to tell the DNS mail.mydomain.com to point to the new I.P address rather than the previous address, which I did yesterday.

We still aren't receiving mail to the new address, should it take this long, is there anything else I need to check or change on the SBS 2008 (exchange) server? Or is it a case of just waiting a bit longer?

If I ping mail.nydomain.com it does seem to be picking up the new i.p address but no 'reply'.
Question by:MadPC

Expert Comment

ID: 40525298
Is the port 25 opened (check FW also)?

run nslookup to check if the MX updated.
Depending on the MX timeout it might take up to 3 days for it to update worldwide.
LVL 14

Expert Comment

by:Andy M
ID: 40525314
Has your router been configured for the new IP or is it a new router? Is the IP address you have been given static or dynamic? (If it's dynamic speak to whoever provided it to get you a static IP otherwise email won't work correctly)

Typically the things to do would be:

1. Configure router for new IP address, test and ensure it is working (do a "whats my ip" from the server). If it's a brand new router configure port forwarding for port 25 and 443 to go to the exchange server.
2. Change MX/dns records so the primary mail record (mail.domain.com) points to the new IP address.  
3. Await dns propagation - typically 24-48 hours depending on your domain host setup. I tend to find most major email providers/dns providers pick up the update within a few hours.

If you have access to a computer that's not on the same network as the server you could also run a telnet test to the IP/dns name to ensure mail flow is working.
LVL 76

Expert Comment

by:Alan Hardisty
ID: 40525343
You will also need to ask your ISP to setup Reverse DNS on your new fixed IP Address or some emails will start to bounce.

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Expert Comment

by:Glenn M
ID: 40525647
Make sure on SBS you re-run the 'Configure E-mail and Internet Connection Wizard'. If you don't start seeing mail flow (which you should by now), run a DNSreport at www.dnsstuff.com and pay particular attention to the sections related to email. Any problems should be identified there.

Author Comment

ID: 40526623

First thing I should confess, in my original post i suggested that if I pinged mail.mydomain.com it showed up the new I.P address - This isn't the case, or at least it isn't today - I may have made an error here as the new I.P is very close to the old one numerically.

@basil2912 - I've ran an nslookup, unfortunately it times out. Is there anyway to speed up the 72 hour process or at least find out if there is a way we can check progress of the change?

@Andy Morton - Nothing is different on the internal network, we have literally uprooted and moved all equipment to the new office, the only thing which has changed is the external (static) I.P address - I'm going to try telnet shortly to see what this throws up.

@Alan Hardisty - I've never heard of this before is it commonplace to do this? Our ISP hasn't changed, we are still with the same provider.

@Glenn M - I've ran the domain through dnsstuff.com, it threw up and error on the email
"All connections to Mailservers port 25 have failed. The standard port for SMTP transactions is 25, so your servers should be operating on that port. It is recommended that it be fixed in order for your mail service to operate properly. The Mail Servers that failed are:

84.xx.xx.xxx | failed message send with: failed cx open with: failed socket connect with: Operation now in progress

A telnet test also times out

Amy other suggestions welcomed!

Author Comment

ID: 40526799
As it turns out, I just checked the DNS records with the hosting provider and for whatever reason the record hadn't updated and was reporting the previous I.P address

I've just changed it (again) and it definitely seems to have saved now, I'll see how it goes, hopefully by tomorrow morning we should be good!

Author Comment

ID: 40528996


Dnsstuff.com is still reporting the same error
"All connections to Mailservers port 25 have failed.


Telnet to the mail server is still unresponsive


Pinging the mail server I.P resolves to the updated address but the request times out


Re-running the 'Configure E-mail and Internet Connection Wizard' seems successful, although there is no issue with the internet connection, this doesn't solve the mail flow issue


If i put mail.mydomain.com in to an off network browser/connection I get the IIS welcome screen


Running nslookup on the server reports 'unknown' but has a reference to the ISP


I can confirm the router is connected to the correct I.P and the server browser reports the correct I.P at whatsmyip.org
So, at the moment we are no further forward and the mail is not getting delivered - I'm totally at a loss with this so any other suggestions are very welcome!

It's been nearly 48 hours since the address was updated, is this just a waiting game?

Accepted Solution

Glenn M earned 1500 total points
ID: 40529000
As per #4, if there is no issue with an Internet connection for browsing from the server and the ICW successfully completed but you can't telnet to the mailserver at the IP address you are supposed to have, that would lead me to believe that you don't actually have the new address yet.

To back up a bit and take the server config out of the equation, if you just connect a laptop directly to the router configured with the static IP you are supposed to be using, does it, in fact, work at that IP address?

An update for a DNS record should take no more than a couple of hours to propagate.

Assisted Solution

MadPC earned 0 total points
ID: 40529082
Cheers Glenn,

I think I've found the issue, apparently the 'Microsoft Exchange Transport' service wasn't started! I just started it and can telnet in no problem

It looks like for some reason that everytime the SBS is restarted that this service doesn't restart on its own for some reason, anyway that's a question for another day

interesting to learn that the DNS should only take a couple of hours to resolve, I'll bear that in mind if we switch I.P in future :)

thanks for all the suggestions!

Expert Comment

by:Glenn M
ID: 40529083
Glad you finally tracked it down.

Author Closing Comment

ID: 40537508
Found an issue with the Microsoft Exchange Transport service not starting automatically

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