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Eric_26987's avatar
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Jul 15, 2011

IP Forwarding VS - How to Rewrite Destination?

Hey Guys!



I'm currently in the midst of an infrastructure move relocating our services from one network to another in a separate physical location. Some of our clients do not have connectivity to the new location and as a result I need a way to forward their requests from the old site IPs to the new site IPs.



At the old site I have an LTM setup (running 9.4) that will host the IPs that clients currently connect on - what would an irule look like that would forward those requests from the old IPs the new location IPs by placing the new IP in the request in place of the old?



All of our nodes will be at the new location with new IPs so all I have to go on with the old location is the lonely LTM.




Thanks for the assist!


4 Replies

  • Hi Eric,


    Are the clients connecting to IP address that are actually VIP address on the F5? Is there an F5 on the new site?





  • Hi Bhattman,



    Correct, the clients are connecting to VIPs on the LTM at the old site. I have a LTM at the new site where our nodes will be moved to. The IP space is diffenent between the sites I need some way for the old LTM to update the destination IPs of the requests it gets to a virtual address on the new site LTM and forward it along.






  • Why don't you test the new LTM Setup to verify that the application works properly and then execute a DNS Change to gracefully migrate the application from one LTM to the other?



    During the implementation (or prior to it) you could add the new LTM Virtual Server IP Address into the OLD LTM Server Pool and then disable the servers. That would effectively make the OLD LTM a Client to the new LTM during the transition and anyone connecting to the old or new would get sent to the new servers (preventing the need for any data reconciliation).



    Does this make sense?
  • Oh. If you do this:




    add the new LTM Virtual Server IP Address into the OLD LTM Server Pool and then disable the servers.




    Don't forget to Enable SNAT Automap on the OLD LTM Virtual Server.