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clintgx_287644
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Aug 26, 2016

Persistence which doesn't bypass the LTM

Hey,

 

I'm trying to configure an F5 LTM with sticky sessions but I'm having a problem with sessions bypassing the load balancer. I've tried dest_addr and cookie so far with no luck. I need all traffic to go through the load balancer.

 

Can someone please advise me what I am doing wrong or which persistence profile to use so the sessions go through the load balancer.

 

Thanks, clintgx

 

2 Replies

  • Can you clarify what you mean by 'sessions bypassing the load balancer'? Based on face value this generally indicates a routing issue in the rest of the network infrastructure. (Or a server responding with hard-coded links to itself in some cases...)

     

    'Upstream' routers will need to route F5 objects (VIPs for various listeners) to the LTM. 'Downstream' routers will need to route return traffic back to the LTM. If your LTM is not in-line with the default routing pathway, you may need to set up features such as SNAT or policy-based routing to ensure return traffic traverses the LTM.

     

    Persistence is used by LTM to ensure connections are sent to the same pool member based on a trait (cookie, source IP, etc.). It does not impact routing outside of the device.

     

  • Client <> F5 <> Servers

     

    As long as the traffic flow is set up such that it is going through the F5 in the clientside and serverside, normal persistence processing will happen. If you want to force return traffic from servers to pass through the F5, you can utilize SNAT.