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aquispe17_31055's avatar
aquispe17_31055
Icon for Nimbostratus rankNimbostratus
May 20, 2018

iRule to forward traffic based in state pool member

Hi eveyone, I have my F5 connected with 3 Internet Service Provider. I have a pool with 3 pool members: Router Provider A, Router Provider B and Router Provider C. I have an irule to take decision about outgoing traffic.Look at this: if { [IP::addr [IP::client_addr] equals 192.168.2.170/32 }{ pool Pool_xxx snat X.X.X.X Today, if the Router o link of Service Provider is down, I manually edit the Irule and change the Source Nat for the IP of other Provider. How can i do this automatically with an irule?? Foe example, if ip address == Y.Y.Y.Y and the Router A is down, then snat is Z.Z.Z.Z. Any idea?

 

application delivery
BIG-IP
big-ip ltm
iRules
  • Simon_Blakely's avatar
    Simon_Blakely
    Icon for Employee rankEmployee
    May 20, 2018

    So you have a gateway pool, with gateway_icmp monitors (maybe with a transparent monitor).

    You need to select the appropriate SNAT IP address based on the selected outgoing router.

    I would apply priority group settings so that you have a preferred router (10.0.0.1) and fallback routers (10.0.0.2, 10.0.0.3).

    Then use an irule similar to the following: 
        when CLIENT_ACCEPTED {
      if {[LB::status pool default_gateway_pool member 10.0.0.1 0] eq "up"}
         Preferred router 10.0.0.1 up, so use correct SNAT
        { snat 10.1.0.1 }
      elseif {[LB::status pool default_gateway_pool member 10.0.0.2 0] eq "up"}
         Preferred Router not up, Fallback1 router 10.0.02 up, 
        { snat 10.2.0.1 }
      elseif {[LB::status pool default_gateway_pool member 10.0.0.3 0] eq "up"}
         Preferred router, Fallback1 router not up,
        { snat 10.3.0.1 }
      }

    I hope this helps.