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d6kimbia_295401's avatar
d6kimbia_295401
Icon for Nimbostratus rankNimbostratus
Oct 13, 2016

Virtual Server (type: standard) is not directing traffic to pool

I have an LTM appliance running BIG-IP 12.1.0 with a VS created, pointing at a pool containing two nodes. I can see the connected devices, all are responding to ICMP requests, and are in the same subnet, however navigating to the address of the VS does not take me to either load balanced node. To troubleshoot, I fired up tcpdump and tried to curl the VS address with an empty reply.

 

The nodes however, if I curl their addresses I immediately get a response from nginx (the application running).

 

Any insight? I suspected initially SNAT may be a solution point here, though when I go to compare the LTMs we have in production (and are managed by a third party), there are no SNAT pools or lists in use for the VS pointing to the child pools.

 

Thank you!

 

application delivery
BIG-IP
LTM

3 Replies

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  • Vijay_E's avatar
    Vijay_E
    Icon for Cirrus rankCirrus
    Oct 13, 2016

    Can you curl from F5's bash shell to the pool members ?

     

    I suspect it is a SNAT issue. Just for testing purpose, can you add automap to the VS ?

     

  • R_Marc's avatar
    R_Marc
    Icon for Nimbostratus rankNimbostratus
    Oct 13, 2016

    If you are running in one-arm mode, you likely need to select automap (or create and use a snat pool).

     

  • TayF5un's avatar
    TayF5un
    Icon for Nimbostratus rankNimbostratus
    Oct 13, 2016

    Could be asymmetric-routing problem. If you are running on inline mode, you can use irule;

     

    when CLIENT_ACCEPTED {

     

    if { [IP::addr [IP::client_addr] equals x.x.x.x] } {

     

    snat automap

     

    pool your_pool

     

    }

     

    }