Forum Discussion

ping-t's avatar
ping-t
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Aug 26, 2025

Round-robin method not load balanced

I have configured BIG-IP 1600 to distribute the load to two servers in a round-robin fashion, but only one of them is communicating and the load is not distributed. We have confirmed that all Pool N...
LTM F5
round robin
nocturnal_soul's avatar
nocturnal_soul
Icon for Altocumulus rankAltocumulus
Aug 28, 2025

You can give this a shot. Think this might work:

  1. Enable SNAT Automap on the virtual server and retest connectivity.
  2. Validate real-server routing to force replies via the BIG-IP (use traceroute).
  3. Confirm VLAN/subnet assignments and Self IP coverage for all pool member subnets.
  4. Tighten health monitors to verify full application functionality, not just TCP.
  5. Capture and review packets on both BIG-IP and real servers to trace asymmetric drops.

By systematically addressing SNAT and asymmetric routing first—and then verifying VLAN, health-monitor, and firewall settings—you can restore true round-robin distribution across both servers.

ping-t's avatar
ping-t
Icon for Altostratus rankAltostratus
Aug 30, 2025

For the first, SNAT Automap is enabled on the virtual server.

  • Aswin_mk's avatar
    Aswin_mk
    Icon for MVP rankMVP
    Sep 03, 2025

    Hi ,

     

    Both of the servers are in same VLAN? also i hope you have enabled layer7 monitor in both servers(ping or tcp will make server up if service down.).  also for fix you can try

    • Enable SNAT Automap on the Virtual Server (for quick test), or
    • Configure a proper return route on both servers pointing back to the F5 Self IP.