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Herman2024's avatar
Herman2024
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3 months ago

which virtual server will be hit?

Hi, we created following virtual forwarding server for internet traffics on LTM. 

     virtual server : internet-vs

     source ip: 192.12.0.1 ( downstream firewall external interface IP)

     destination: 0.0.0.0/0

  For the return traffics of this VS, do we need to create another virtual server?    If we create a new virtual forwarding server like below, will the return traffics of VS "internet-vs" hit this VS "Test-VS"? 

     virtual server: Test-VS

     source: 0.0.0.0/0

     destination: 192.12.0.1

Can someone please advise? Thanks in advance! 

 

  

2 Replies

  • Hello Herman2024​ 

    Noticed there was a response from AXI_MJ and wanted to encourage you to update your post if it has helped answer your question or if you have follow up questions. 

    -Melissa 

  • For normal return traffic, you would not usually need a second forwarding virtual server.

     

    Once the initial flow hits internet-vs, BIG-IP creates a connection table entry for that session and keeps the flow state (including things like the return path / last hop information). So if the original flow is something like:

     

    192.12.0.1:10729 -> 1.1.1.1:80

     

    the return traffic:

     

    1.1.1.1:80 -> 192.12.0.1:10729

     

    would normally be matched against the existing connection entry and forwarded as part of the same flow, rather than hitting a different forwarding VS.

     

    I’d only expect another forwarding VS to matter if this is actually a new connection, or if the return traffic does not match the existing flow tuple/state.