iRule to change IP destination

First, thanks for your help. Here are the details about my configuration. Im using BIG-IP for a VOIP platform. Its unusual specially as BIGIP is not used as a load balancer but mainly as a packet inspector that redirect the SIP traffic to certain SIP Application server directly plugged to the BIGIP.

 

 

The VS I am using to apply the iRules is a Standard VS, Destination = Network (0.0.0.0/0.0.0.0), configured for UDP, port 5060, with a SIP Profile.

 

Hence, in virtual address list I have only 0.0.0.0.

 

 

There are 4 machines directly plugged to the BIG-IP. Here is the type of things I want to achieve:

 

on eth0, one phone is connected to the BIG-IP. It is in VLAN1 (untagged).

 

on eth1, there is a call manager connected to the BIGIP. It is VLAN2 (untagged).

 

on eth2, there is a SIP AS. It is VLAN3 (untagged).

 

 

They all belong to a VLAN Group. I have added one route which is "Use Gateway 192.168.100.1" so that all traffic goes through BIGIP. The three machines are all in the same VLAN, the traffic is then untagged.

 

 

What I want to achieve is to redirect the traffic for certain SIP messages. For example, I have defined an iRule with:

 

if {[SIP::method] equals "NOTIFY"} {

 

pool SIPApplicationServer_pool

 

}

 

 

where SIPApplicationServer_pool is a pool defined with only one member.

 

 

It does the job: when a phone on eth0 sends a NOTIFY to the call manager on eth1, BIG-IP applies the iRule and sends

 

the packet to eth2 instead. The problem is:

 

 

- in my VS: if Address Translation is disabled, I can see the packet on the SIP AS with Wireshark, but the IP Destination address did not change. It is still the IP address of the call manager. Same if I use the command node.

 

 

- If Adress Translation is enabled, it works! But all the traffic gets stuck in the BIG-IP. It doesn't know where to send the packets anymore. I see them entering but not going out.

 

 

David