Forum Discussion

Thiyagu_343098's avatar
Thiyagu_343098
Icon for Nimbostratus rankNimbostratus
Sep 20, 2018

query on static NAT

Hi, we have design like the traffic from the client to LB is not getting SNAT so the source IP will be preserverd all the way to the application servers.

 

As far as the reverse traffic is concerned, we have a static NAT is configured on LB to change the source IP of the traffic flow to the VIP IP of LB.

 

we have alos VIP of type "forwarding IP" for routing based on host IP for the traffic from the server to LB.

 

for some reasons I was told the traffic from the server is not getting NATed to the IP of VIP.

 

Please let me know do I need to associate the NAT to the VIP to take effect of it?

 

Or does NAT object match for the specfic traffic flow and does the translation?

 

application delivery
BIG-IP
LTM
  • AlanTen's avatar
    AlanTen
    Icon for Altostratus rankAltostratus
    Sep 20, 2018

    If you're not using SNAT and are preserving the client's real IP address all the way to the application servers then you will need to ensure that either you use the F5 VIP as the default gateway for the application servers or a network design/routing that will ensure that the return path traffic goes back to the F5.

     

    Associating NAT to the VIP will ensure that the traffic returns via the F5 and is applied by using "Source Address Translation : AutoMAP" or "Source Address Translation : SNAT : user defined SNAT pool".