Forum Discussion

Chandru_14793's avatar
Chandru_14793
Icon for Nimbostratus rankNimbostratus
Aug 28, 2011

Routing in LTM

Hello,

 

 

I have F5 LTM V9.4.8

 

 

I could see traffic from end hosts reaching the bigip internal interface through tcpdump utility

 

 

but I dont know what happens next, how do I find out if the F5 rejects (drops) the packet or sends it to a different destination router

 

 

Thanks,

 

Chandru

 

basic
getting started
new to f5

1 Reply

  • Hamish's avatar
    Hamish
    Icon for Cirrocumulus rankCirrocumulus
    Sep 27, 2011
    That depends on what options you have set on the VS... There's 3 basic options

     

     

    1. n-path. Just perform a tcpdump on interface 0.0 and watch the packets come in and the packets go out. The response packets probably aren't passing back through your LTM, so you wouldn't necessarily see the returns (THat's not 100%. If you're routing back through the LTM you will see them).

     

     

    2. Routed with NAT destination. Perform a tcpdump on 0.0 and use a filter that allows you to see both the client side (client IP + VS IP:Port) and server side (client IP + pool member IP:Port).

     

     

    3. SNAT... That's more difficult if you have lots of traffic. If it's just you accessing it, then modify the filter in the second option to use the SNAT IP address and pool member IP:Port on the server side connection.

     

     

    The LTM will only reject the packet under a small number of circumstances... If everything is up and running, and the VS is green, everything configured correctly, it should go through fine. Are you having problems somewhere?

     

     

    H