Forum Discussion

Gonzalex_330537's avatar
Gonzalex_330537
Icon for Cirrostratus rankCirrostratus
Dec 07, 2017

How to assign SNAT Object (not SNAT Pool) to Virtual Server?

All, would you please help me clarify the following SNAT doubts.

 

The page at https://support.f5.com/kb/en-us/products/big-ip_ltm/manuals/product/tmos-routing-administration-11-6-0/7.html states the following, in regards to SNAT:

 

"You must assign the SNAT to a virtual server."

 

I know I can attach a SNAT-Pool to a virtual server but, I cannot find a way to assign a SNAT object to a virtual server!

 

  1. Is the documentation wrong?
  2. Should the documentation be correct, how do I assign a SNAT object (not snat pool object) to a virtual server
  3. Assuming the documentation is wrong, what is the point of creating a snat object then, given that I can create a snat_pool and assign it to a vs right away!?

Thanks in advance.

 

application delivery
LTM
TMOS
  • Surgeon's avatar
    Surgeon
    Ret. Employee
    Jun 05, 2018

    BIG-IP has three types of snat objects: ip address, snat pool and automap.

     

    Did it answer your question?

     

  • youssef1's avatar
    youssef1
    Icon for Cumulonimbus rankCumulonimbus
    Jun 05, 2018

    Hi Gonzalex,

     

    You have 3 types of SNAT:

     

    Source Address Translation : Auto Map

     

    the F5 is SNATing (translate source address) to a floating-ip (if cluster) or self-IP (if standalone) in the egress interface.

     

    Source Address Translation : Snat Pool

     

    In this case, when you create a snat pool even if you don't assign snat pool to a virtual server, IP set in the snat pool will be notify to the network (ARP). So user can Ping this IP... If you want to nat user request with SNAT POOL IP you have to set it on your VS.

     

    additiona, snat is initiated from one direction depending on configuration.

     

    Source Address Translation : NAT

     

    In this case NAT provides a routable address for sending packets to or from a node that has a private class IP address. So you don't need to use it trough an Virtual Server.you might want to allow a client on an external network to send a request directly to a specific internal node (thus bypassing the normal load balancing server selection).

     

    So tu sum up you don't need to set NAT in VS in order to use it. You can use NAT just by create NAT Rules...

     

    https://support.f5.com/kb/en-us/products/big-ip_ltm/manuals/product/tmos-routing-administration-11-6-0/7.html

     

    Let me now if it's clear...