Exchange settings for Gateway change

We have a Server running Exchange with a default gateway of on a cisco 877 (iPrimus line). I would like to change gateways on the server  to a different router, cisco 851, gateway (Telstra Line).

What do i need to consider in terms of Exchange, SMTP, DNS and MX settings to ensure that exchange will continue to work after I have done the switch?

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danmax1979Author Commented:
Additional info: We are currntly using a smart host that i assume will also need to be changed to a telstra equivalent
BusbarSolutions ArchitectCommented:
if both are going from the same ISP then nothing.
if they use different ISP then you will need to update the MX record and PTR records as well as your web mail URL
Hypercat (Deb)Commented:
The internal IP address ( changing to is not the issue.  Is your EXTERNAL IP address changing?  The only reason you would need to make any changes would be if that external IP will be different. Other than that, you just replace one router with the other and make sure to configure all of your firewall and packet forwarding/filters the same as on the old router.

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Hypercat (Deb)Commented:
One other thing - you need to make sure that the internal default gateway on all of your servers/workstations is also changed from to
danmax1979Author Commented:
Thanks for that, external ip address IS also changing.
BusbarSolutions ArchitectCommented:
so you will need to change
mx records IP
PTR records IP
web mail A record  IP
Ensure the router/firewall is forwarding incoming smtp traffic to your server.
Will need to change your servers NIC Gateway to point to the .254 address, rather than the current .1 address.

If you forward email to a smart host, update that to your new ISP smart host.
If you forward unresolved recipients to a smart host, update that ot your new ISP smart host.
DNS on your server, if you have DNS forwarders manually assigned, update these to your new ISP DNS servers.

As mentioned previously, your MX record on the domain you email from will need to point to your new external staic IP address and the associated rDNS record will need updating to your new static IP address (your ISP does this, not you).
danmax1979Author Commented:
Hi Guys,

Just an update on the situation here, I have had our MX records modified and everything is now working, mail going in and out etc.

We ended up creating a new mx record and also kept our old one as a backup incase we need to switch back at some time.

Recently (last few months) we have been having some issues with spam being sent to AND from our domain. Now that i have made this change there are a heap of recipients in the Queue getting "Delivery Status Failure" messages stuck in a "Retry" state. The thing is the majority of these recipients look like they are spam type addresses (see attached image).

This is probably a good thing but there are also the odd good address getting caught in this state. Is there something I may have forgotten or is it a case of some people perhaps not recognizing (or permitting) the new address?

danmax1979Author Commented:
Also just noticed that under the SMTP server properties, in the Advanced option on the Delivery tab, Masquerade Domain is set on

Should this be changed to
danmax1979Author Commented:
Ok I have implemented that, and i will monitor the performance over the coming days.

Thanks everyone for your help.
Shreedhar EtteCommented:
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