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suthomas1
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Apr 02, 2019

Dynamic nat

Hello,

 

In setting up a virtual service, when should automap be used? is Dynamic NAT same as automap. Please help.

 

  • Hi Thomas,

     

    SNAT:

     

    Snat Automap will Nat the client request with F5 degress interface. So SNAT Automap will allow you to avoid asymmetrical routing. The backend will response to F5 instead client (SNAT is usually utilized when you need to translate the original client IP to that of the SNAT IP. It is also used to make sure that the return traffic is passed to the F5)...

     

    If you need more details about snat you can check this article:

     

    https://support.f5.com/csp/article/K7820

     

    NAT:

     

    NAT is utilized to provide access to non-routeable addresses (RFC1918). Traffic flow initiation is bi-directional

     

    In some cases, 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). To send a request directly to an internal server, a client normally needs to know the internal node’s IP address, which is typically a private class IP address. Because private class IP addresses are non-routable, you can instead create a network translation address (NAT). A NAT is a feature of BIG-IP Local Traffic Managerthat provides a routable IP address that an external node can use to send traffic to, or receive traffic from, an internal node.

     

    More specifically, a NAT is an address translation object that instructs Local Traffic Manager (LTM) to translate one IP address in a packet header to another IP address. A NAT consists of a one-to-one mapping of a public IP address to an internal private class IP address.

     

    Comparison of NATs and SNATs:

     

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