Forum Discussion

Srikar's avatar
Srikar
Icon for Altostratus rankAltostratus
Apr 01, 2021

Understanding SNAT

SNAT pool is configured but source translation is set to None on Virtual Server and there is a pool attached to it which has Allow SNAT as yes? Does translation happens in this case when client send...
application delivery
BIG-IP
LTM
  • Nikoolayy1's avatar
    Nikoolayy1
    Apr 12, 2021

    Yes, if you have such configuration as this is outside the F5 Virtual servers (VIP) configuration and it works for all traffic matching this SNAT object. The idea is if you want to use the F5 devices just as NAT/SNAT devices without load balancing, you use those objects. You read the article below on how this is done:

     

     

    https://support.f5.com/csp/article/K47945399

     

     

    Please also read this as if you have VIP with snat pool or auto map and NAT and SNAT separate objects the VIP SNAT config takes priority over the NAT and SNAT objects. If the VIP does not do source translation then if there are matching NAT and SNAT objects, they are used as the NAT has higher priority than the SNAT. If there is no NAT object and the VIP does not do translation, then the SNAT is used.

     

     

    https://support.f5.com/csp/article/K9038

Srikar's avatar
Srikar
Icon for Altostratus rankAltostratus

Thanks for the response. I see SNAT List defined with Translation set to use SNAT Pool. So, As per my understanding if SNAT list is defined, F5 will do the translation even SNAT set to None on VS. is it correct?

Nikoolayy1's avatar
Nikoolayy1
Icon for MVP rankMVP
Apr 12, 2021

Yes, if you have such configuration as this is outside the F5 Virtual servers (VIP) configuration and it works for all traffic matching this SNAT object. The idea is if you want to use the F5 devices just as NAT/SNAT devices without load balancing, you use those objects. You read the article below on how this is done:

 

 

https://support.f5.com/csp/article/K47945399

 

 

Please also read this as if you have VIP with snat pool or auto map and NAT and SNAT separate objects the VIP SNAT config takes priority over the NAT and SNAT objects. If the VIP does not do source translation then if there are matching NAT and SNAT objects, they are used as the NAT has higher priority than the SNAT. If there is no NAT object and the VIP does not do translation, then the SNAT is used.

 

 

https://support.f5.com/csp/article/K9038