irule for base on source ip

Hi Hung, You can add nodes to the F5 with the ping monitor. For example each ISP has customer edge router/device that maybe pingable by your F5. You would add the customer edge router as a node and put a ICMP ping as the default monitor for the node. Then you modify the irule to check for the UP/DOWN Status of the node

For Example

when CLIENT_ACCEPTED {
 if {[IP::addr [IP::client_addr] eq 10.0.x.y]}{
       if { [LB::status node IP_ADDRESS_OF_ISP-A_node ] eq "up" } { 
           snatpool NAT_MAILServer member 255.255.x.y
       } elseif { [LB::status node IP_ADDRESS_OF_ISP-B_node ] eq "up" } {
           snatpool NAT_MAILServer member 183.91.x.y 
       } elseif { [LB::status node IP_ADDRESS_OF_ISP-C_node ] eq "up" } {
           snatpool NAT_MAILServer member 118.69.x.y
       }
 else
    if { [LB::status node [LB::status node IP_ADDRESS_OF_ISP-A_node ] eq "up" } { 
           snatpool NAT_MAILServer member 255.255.x.z
       } elseif { [LB::status node IP_ADDRESS_OF_ISP-B_node ] eq "up" } {
           snatpool NAT_MAILServer member 183.91.x.z
       } elseif { [LB::status node IP_ADDRESS_OF_ISP-C_node ] eq "up" } {
           snatpool NAT_MAILServer member 118.69.x.z
       }
 } }

I hope this helps

-=Bhattman=-