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SivaYenduri's avatar
Dec 03, 2019
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How does F5 select the IP from SNAT pool to communicate with backend server

Hello All,

 

We have an LB setup and 2 backend servers are configured behind the VIP ip.

We have to troubleshoot a File transfer issue and we need to capture the packets on server and client as well.

We have a SNAT pool (with 10 IP addresses) configured on the VIP.

To capture the packets on the backend server, we need to know the source IP which LB selects from the SNAT pool.

Can someone explain how LB selects the IP from the SNAT pool to communicate with backend server?

 

  • Hi SivaYenduri,

     

    I was able to find a small note in our SNAT feature article that explains this. The system will load balance connections between the SNAT pool addresses based on which members have the least connections.

     

    "Note: The BIG-IP system load balances SNAT pool connections between members using the least connections algorithm."

     

    K7820: Overview of SNAT features

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

     

    -Nathan F

2 Replies

  • Hi SivaYenduri,

     

    I was able to find a small note in our SNAT feature article that explains this. The system will load balance connections between the SNAT pool addresses based on which members have the least connections.

     

    "Note: The BIG-IP system load balances SNAT pool connections between members using the least connections algorithm."

     

    K7820: Overview of SNAT features

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

     

    -Nathan F

    • SivaYenduri's avatar
      SivaYenduri
      Icon for Cirrus rankCirrus

      Hello Nathan,

       

      Thanks for the reply. The document is informative.

      Appreciate your help.

       

      Best Regards

      Siva