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Bhavik_1402's avatar
Bhavik_1402
Icon for Nimbostratus rankNimbostratus
Apr 12, 2021

Self IP in different subnet and VS and pool members are in same subnet then Self ip

Hi Team,   I'm working on one of the installation where the requirement is that VS - e.g 10.10.10.X and pool members are in same subnet 10.10.10.X whereas F5 Self IPs will be in different subnet ...
application delivery
BIG-IP
different subnets
LTM
routing
vs
Heino's avatar
Heino
Icon for Cirrus rankCirrus

Will F5 be the router for the 10.10.10.0/24 network? Will it provide the default gateway for the servers?

 

If this is the case then traffic hitting the VS will be sent on to the server without going by the switch-router. No significant difference compared to a setup with the gateway on a switch-router. The benefit of having the default gateway on F5 is that you don't have to snat the client requests. Instead of using automap or snat pool you can use the original client IP. This is very useful for loadbalancing radius requests.

Bhavik_1402's avatar
Bhavik_1402
Icon for Nimbostratus rankNimbostratus
Apr 15, 2021

Thanks Heino,

 

F5 will not be router for 10.10.10.0/24 network as it will be on switch and pool members(servers) gateway will be switch so we need to use SNAT. I am still not clear on how the routing/switching or traffic will flow.

  • Heino's avatar
    Heino
    Icon for Cirrus rankCirrus
    Apr 18, 2021

    I seriously hope that SanjayP's answer works foryou, because I can't recommend what I'm about to reply. Absolutely avoid the following if possible. It will only give you a headache.

     

    I've had to resolve a similar problem previously on a competing platform. It wasn't the same though. My VS was in a different subnet, I just had to SNAT to a subnet that would route differently that standard.

    Traffic flow:

    1. I used SNAT to map the communication from reverse-proxy to the server.
    2. Then I used Policy Based Routing, based on source address (your SNAT pool) to ensure that that network segment is routed through your desired gateway address (10.10.20).