NAT rules for Email exchange/Email Gateway

[Samerrafidsaleem]

Hi Everyone,

I have two IP addresses used for inbound/outbound emails on our email gateway.

I have created the attached rules NAT and Security and I wanted to get opinions if its correct because I tested it and it seems something wrong that prevent emails from in/outbounding and even the web mail access did not work...your advice please.

thanks

[OtakarKlier]

Hello,

I'm sure there is a reason you have two external IP's for this? But it can be accomplished with one. Check out this article on NAT.

https://knowledgebase.paloaltonetworks.com/KCSArticleDetail?id=kA10g000000CllzCAC

Hope it helps.

[Samerrafidsaleem]

Hi

I have one external IP, but two private ip addresses for the email gateway 

first ip for outbound 172.16.16.22

second for inbound 172.16.16.23

these in dmz

and for web mail access for the exchange I have 10.211.0.30 which is on the inside interface.

[Samerrafidsaleem · Accepted solution]

Ok, so after lot of checking.

turned out to be ARP on the Router was keeping the exchange IP address with the old Firewall MAC address which caused the traffic from the exchange to be dropped.

all I had to do is to change ARP age out time to 30 seconds.

all is good and the rules were correct.