Forum Discussion
phil_71791
Nimbostratus
NimbostratusSMTP thru F5 issue
we put up a new smtp server up and are running it thru the F5. only one problem left to solve.
the server is NAT thru the F5, and the server has two nic's both with a private IP and the F5 NAT's it to an external IP. this is working but when we send an email from the smtp server thru the F5, it is stamping the email with the IP of the F5 box not the NAT'd address.
so Yahoo and others are trying to do a reverse lookup of the IP the F5 uses for itself.
Is there a way to have the F5 box stamp the email with the external IP of the smtp server.
3 Replies
hwidjaja_37598Altostratus
What mail software are you using? If Postfix, I'm not sure whether you can use 'proxy_interfaces' setting to change this IP.
If it doesn't work, I guess you might be able to configure a VS and use TCP::payload to modify it.
Let us know your current configuration or show us the diagram.- Nat_Thirasuttakorn
Employee
May I ask what do you mean by "stamping the email" ? 
L4L7_53191Fortunately the fix here is easy: create a SNAT address for your email server that matches the Virtual server address that the inbound mail is coming to (i.e. that DNS resolves to). When the outside world then does a lookup it'll see the proper source address / domain name.
-Matt
