Forum Discussion

ccook_14058's avatar
ccook_14058
Icon for Nimbostratus rankNimbostratus
Sep 11, 2014

Virtual Server using external site as pool member, routing problem?

I believe my issue is pretty straight forward but I'm not able to get it going. I'm not able to use an external host ( a host that my F5 does not have direct access to via one of its vlans ) as a pool number. No issues when using any hosts on any of the different vlans connected directly to the f5. I imagine the virtual host doesn't know how to route out of the network to access the external host, I'm just not sure where exactly I should be defining a "Default Gateway" for the f5 to route things?

 

  • Thank you for the replies, the thing that was causing my issue was simply the route. I really wasnt sure what to put in for the route and had used 0.0.0.0 for Destination and 255.255.0.0 for netmask.

     

    After submitting a support ticket they had me put 0.0.0.0 for the netmask on my route. I had looked through the documentation and wasn't able to come up with that on my own, but this is now resolved.

     

    To recap if this can help someone else.

     

    Virtual server could not use externally hosted website as pool member, could use hosts on local vlans fine. Logged onto the f5 couldn't traceroute or ping the external site, obviously no route.

     

    I needed to add a route on the f5 using 0.0.0.0 for the destination and netmask, and then pointed the gateway at my organizations outward bound router.

     

  • As boneyard has said, you configure routes (default or otherwise) 'under' the Networking tab.

     

    You need to consider routing for two things;

     

    • Health Monitors - you'll need to ensure your F5 can reach your Pool Members and that they can respond to the Self IP(s) of the F5. How your routing is setup will determine which interface, VLAN and subnet and thus Self IP is used.
    • Clients - you can SNAT, in which case you the same rules as per Health Monitors apply, or not, in which case you need to ensure your Pool Members route back to the client source IPs via the F5 (not directly). This isn't always possible, hence the common recommendation to SNAT.
  • you define a default route towards the internet most likely.

     

    you can do this in the networking > route section

     

    you will probably have to use source NAT as the external site has to return the traffic to the F5 or you end up with asymmetric routing.