irule to load balance to specific ISP based on source IP

Hi Hawary,

you may use the iRule below on your

IP-Forwarding

• If ISP1 is available it will route traffic from Network 1 to ISP1
• If ISP1 is available it will route traffic from Network 2 to ISP2
• If ISP1 is offline it will route traffic from Network 1 to ISP2
• If ISP1 is offline it will reject traffic from Network 2

Note: You don't have to care if ISP2 is offline - simply try to send traffic to ISP2 as gateway of last resort and see what happens. If ISP2 is down the traffic will be dropped anyway...

when CLIENT_ACCEPTED { 
    if { [IP::addr [IP::client_addr] 10.10.10.0/24] } then {
         Section for Network 1
        if { [active_members GW_ISP_1_POOL] > 0 } then {
             ISP 1 is online. Use VS default settings and local routing table.
        } else {
             ISP 1 is offline. Setting SNAT IP and Nexthop (aka. routing table overwrite) to ISP2
            snat 222.222.222.10 ; Your IP for ISP2
            nexthop 222.222.222.1   ; Def-GW of ISP2
        }
    } elseif { [IP::addr [IP::client_addr] 10.20.20.0/24] } then {
         Section for Network 2
        if { [active_members GW_ISP_1_POOL] > 0 } then {
             ISP 1 is online. Setting SNAT IP and Nexthop (aka. routing table overwrite) to ISP2
            snat 222.222.222.10 ; Your IP for ISP2
            nexthop 222.222.222.1   ; Def-GW of ISP2
        } else {
             ISP 1 is offline. Reject access for Network 2.
            reject
        }
    } else {
         Undefined traffic will use VS default settings...
    } 
}

Note: If you utilize the

IP-Forwarding

snat

nexthop

Cheers, Kai