[Help] How to write iRule to select default gateway based source IP address?

Hi,

you can use an irule like this one (rule edited after Kai comments about IP::addr performances):

when RULE_INIT {
    array set static::SnatPolicy {
        "10.1.1.1" {"Pool_ISP1" "178.102.1.105" ""}
        "10.1.1.2" {"Pool_ISP1" "178.102.1.104" ""}
        "default" {"default_gateway_pool" "178.102.1.104" "122.255.27.144"}
    }
}

when CLIENT_ACCEPTED {
     Check if destination address is local
    if {[IP::addr [IP::local_addr] equals 192.168.0.0/16] || [IP::addr [IP::local_addr] equals 10.0.0.0/8] || [IP::addr [IP::local_addr] equals 172.16.0.0/12]} {
        pool internal_router
    } else { 
        if { [info exists static::SnatPolicy([IP::client_addr])]}{
            set clientip [IP::client_addr]
        } else {
            set clientip "default"
        }
        pool [lindex $static::SnatPolicy($clientip) 0]
    }
}

when LB_SELECTED {
    if { [IP::addr [LB::server addr]/28 equals 178.102.1.96]} {
        set link 1
    } else {
        set link 2
    }
    snat [lindex $static::SnatPolicy($clientip) $link]
}

Hi, Stanislas Piron.

 

I understand.

 

Thank you.

 

Hi Destiny,

Stanislas has shown you a setup based

[array]

information and gateway pools. Let me show you a less integrated and complex setup based on a L2-Forwarding Virtual Server and a slightly less complicated iRule.

Prequisite:

1. Establish a L2-Forwarding Virtual Server and a default route-table for your environment.
2. Figure out all the required exemption of this default route-table (sort of PBR thinkering)
3. Customize the iRule below to selectively overwrite your default routing table.

iRule:

when CLIENT_CONNECTED {
    if { ( [IP::addr [IP::local_addr] equals "10.0.0.0/8"] ) 
      or ( [IP::addr [IP::local_addr] equals "172.16.0.0/12"] )
      or ( [IP::addr [IP::local_addr] equals "192.168.0.0/16"] ) } then {
         This is the section for traffic destined to internal IPs
         The traffic is handled by the regular routing table.
    } elseif { [getfield [IP::client_addr] "%" 1] equals "192.168.10.101" } then {
         This is the section for traffic orginating from IP 192.168.10.101
         Set the SNAT IP to 178.102.1.105
        snat 178.102.1.105
         Set the next-hop to 178.102.1.104
        next-hop 178.102.1.104
    } elseif { [getfield [IP::client_addr] "%" 1] equals "192.168.10.102" } then {
         This is the section for traffic orginating from IP 192.168.10.102
         Set the SNAT IP to 178.102.1.105
        snat 178.102.1.105
         Set the next-hop to 178.102.1.104
        next-hop 178.102.1.104
    } else {
         This is the section for the remaining traffic
         Set the SNAT IP to 122.255.27.145
        snat 122.255.27.145
         Don't overwrite the next-hop to rely on the routing table
    }
}

Cheers, Kai

Hi, Kai.

 

I will try it.

 

Thank you.