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Amyoussef's avatar
Amyoussef
Icon for Nimbostratus rankNimbostratus
Nov 03, 2022

F5 ltm load balancer

Hello,  We have a routers load balancing problem. We have one pool that contain two routers isp1 and isp2 with round robin and icmp health monitor. One virtual server that handle traffic from lan ...
application delivery
  • Mohamed_Ahmed_Kansoh's avatar
    Mohamed_Ahmed_Kansoh
    Nov 04, 2022

    Hi Amyoussef , 
              I see that this issue is arising out of breaking a stateful connection when turning off one of your pool members which means one of your router.
    I do not know what type of virtual servers do you use in this implementation , but I would like to share with you a solution from my perspective. 

    > First , go to ( Local traffic > Pool > choose your pool > select properties > Select advanced in configuration field > then Action On Service Down and choose "reselect" Option ). 

    > By enabling " Action On Service Down" feature you make a quite stateful connections and maintains it when one of your routers become unavailable. 
    Please note , you need to adjust your virtual server such as ( not using tcp profile and disable Port and address translation ) , also if the traffic goes through a firewall to internet you need make sure that traffic will be allowed through this firewall if one of routers become unavailable. 

    > Please refer to this KB as well , it will help you to configure "Action On Service Down" feature well : 


        https://support.f5.com/csp/article/K15095

    I hope you get ride of your issue soon. 
    Goodluck 

Paulius's avatar
Paulius
Icon for MVP rankMVP
Nov 06, 2022

AmyoussefIn this topology does your BIG-IP have to act as your gateway to your ISP routers? If not you would probably benefit more from having your own edge router or firewall and configuring ECMP on it and point to ISP1 and ISP2 routers. You can then move your F5 further down from the edge and have it handle load balancing for websites, applications, and various other tasks that it is more suited to handling. If you must use the BIG-IP as your edge then Mohamed's response could fix your issue.