12-11-2013 01:20 PM - edited 03-11-2019 08:16 PM
Hi Guys
can you help me with the following?-
we have an Exchange migration project, so I will need to make changes on the firewall to allow the emails to be delivered on the new server.
having a different IP address on the new server, I will need to create a new NAT rule and access-lists.
the question is if I use port 25 for the new NAT rule it will remove the existing NAT rule which I dont want as the new mail server is still in the testing phase and I dont want to break the connection.
can you please advise how do I test this new server for email sending without removing old one?
I am using a CISCO881 router.
existing NAT rule is-
ip nat inside source static tcp 192.168.1.50 25 interface FastEthernet4 25
and the new server IP will be 192.168.1.100
Thanks
12-11-2013 03:16 PM
Do you have more public IP's than the one assigned to Fa4 or is that the only one?
12-11-2013 03:55 PM
Hi Collin
no I have only one Public IP address.
just a question on top of the question-
what about if I create the new NAT rule with a different external port?
i.e.- ip nat inside source static tcp 192.168.1.100 25 interface FastEthernet4 25230
and then allow the port 25230 on the new server, will that work or I am talking non-sense?
Thanks
12-11-2013 03:58 PM
Using a different port will work fine and since you have only 1 public IP, that is the only way to do it without breaking the production NAT for email.
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