zorba111
asked on
Exchange mailserver stopped working when router was replaced
Because of an ADSL line upgrade we were forced to change our router.
I plugged in the new router, set up the ISP username and password, gave it the right internal IP address (A.B.C.2) and hey presto, we were on the internet again, and VoIP was working.
However, our Exchange mailserver, on the SBS server at A.B.C.253, while able to send mail out, was not collecting any external mail.
We got 5 static IP addresses from our ISP, viz:
" * the network address is: X.Y.Z.192
* your router/hub address is: X.Y.Z.198
* your subnet mask address is: 255.255.255.248 if you have 5 Static IP addresses or 255.255.255.240 if you have 13 Static IP addresses
Your computers can use addresses from X.Y.Z.193 to X.Y.Z.197 "
In DNS our mailserver is set to X.Y.Z.193, but the router is X.Y.Z.198
I think we simply need to set up a route in the router that will convert external IP = X.Y.Z.193 to internal IP = A.B.C.253
correct?
I plugged in the new router, set up the ISP username and password, gave it the right internal IP address (A.B.C.2) and hey presto, we were on the internet again, and VoIP was working.
However, our Exchange mailserver, on the SBS server at A.B.C.253, while able to send mail out, was not collecting any external mail.
We got 5 static IP addresses from our ISP, viz:
" * the network address is: X.Y.Z.192
* your router/hub address is: X.Y.Z.198
* your subnet mask address is: 255.255.255.248 if you have 5 Static IP addresses or 255.255.255.240 if you have 13 Static IP addresses
Your computers can use addresses from X.Y.Z.193 to X.Y.Z.197 "
In DNS our mailserver is set to X.Y.Z.193, but the router is X.Y.Z.198
I think we simply need to set up a route in the router that will convert external IP = X.Y.Z.193 to internal IP = A.B.C.253
correct?
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Eek... Just noticed I posted a config for Cisco routers!
Agree with demazter.
Agree with demazter.
ASKER
thanks guys,
just to point out that NOTHING else has changed, just the ADSL line was upgraded
(AFAIK all our ADSL subscription details are the same, surely the ISP wouldn't change these without notifying us, or have any need to change these?)
...which necessitated a change of router
so @craigbeck, we shouldn't need to change DNS
just to point out that NOTHING else has changed, just the ADSL line was upgraded
(AFAIK all our ADSL subscription details are the same, surely the ISP wouldn't change these without notifying us, or have any need to change these?)
...which necessitated a change of router
so @craigbeck, we shouldn't need to change DNS
ASKER
just to check guys:
The info i got from the ISP is:
" * the network address is: X.Y.Z.192
* your router/hub address is: X.Y.Z.198
* your subnet mask address is: 255.255.255.248 if you have 5 Static IP addresses or 255.255.255.240 if you have 13 Static IP addresses
Your computers can use addresses from X.Y.Z.193 to X.Y.Z.197 "
therefore, any traffic for IP addresses in the range X.Y.Z.193 to X.Y.Z.197 will wind up at our router (with IP address X.Y.Z.198) ?
funny, when I ping the IPs from X.Y.Z.192 to X.Y.Z.198
I get replies from a weird IP address, 81.148.64.1, for all but the "router" IP (X.Y.Z.198).
Is this significant?
The info i got from the ISP is:
" * the network address is: X.Y.Z.192
* your router/hub address is: X.Y.Z.198
* your subnet mask address is: 255.255.255.248 if you have 5 Static IP addresses or 255.255.255.240 if you have 13 Static IP addresses
Your computers can use addresses from X.Y.Z.193 to X.Y.Z.197 "
therefore, any traffic for IP addresses in the range X.Y.Z.193 to X.Y.Z.197 will wind up at our router (with IP address X.Y.Z.198) ?
funny, when I ping the IPs from X.Y.Z.192 to X.Y.Z.198
I get replies from a weird IP address, 81.148.64.1, for all but the "router" IP (X.Y.Z.198).
Is this significant?
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ASKER
Our "new" router is a Draytek Vigor 2800G. I say "new" because we actually used it on the LAN before we got the juniper.
I looked at the Port Forwarding table on the Draytek, and there already is an entry, called SBS-EXCH, which redirects any TCP traffic on port 25, to A.B.C.253, port 25.
So its something else stopping the email reaching the server?
I looked at the Port Forwarding table on the Draytek, and there already is an entry, called SBS-EXCH, which redirects any TCP traffic on port 25, to A.B.C.253, port 25.
So its something else stopping the email reaching the server?
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@tgultekin
there is only an ADSL port on the Draytek, no seperate WAN port...
there is only an ADSL port on the Draytek, no seperate WAN port...
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@tgultekin
I didn't want to change this setting as things seemed to be working "if it ain't broke don't fix it" IIABDFI ? lol.
As it happens we did start to have problems with a banking site after switching routers. I remembered this last post (but not your explicit warning about banking sites - my bad), so came back to it and discovered your solution. So many thanks....
note to self... MultiNAT is mapping internal IP addresses (...NAT) to >1 (...multi) external IP addresses.
see also:
http://www.draytek.co.uk/support/kb_vigor_multinat.html
I didn't want to change this setting as things seemed to be working "if it ain't broke don't fix it" IIABDFI ? lol.
As it happens we did start to have problems with a banking site after switching routers. I remembered this last post (but not your explicit warning about banking sites - my bad), so came back to it and discovered your solution. So many thanks....
note to self... MultiNAT is mapping internal IP addresses (...NAT) to >1 (...multi) external IP addresses.
see also:
http://www.draytek.co.uk/support/kb_vigor_multinat.html
ASKER
tagged my own answer as I got there on my own largely, but others comments helped my overall understanding. Especially tgultekin who helped prevent another problem that arose that wasn't anticipated in the original problem.
ip nat inside source static tcp A.B.C.253 25 X.Y.Z.193 25
Also, you need to check that the DNS for your domain name is correct if you have been assigned a different IP range from what you had before. If you have the same IP range you can ignore the below...
In your DNS zone you need to check the MX record to get the hostname of your mail server, then edit the A record for that host.
So, if your MX record is MAIL.YOURDOMAIN.COM you need to change the IP address for the host called MAIL to X.Y.Z.193