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jenmick1_43986's avatar
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Jan 27, 2012

Inter-VLAN Routing?

Hello all!



I am working with an HA pair of LTM 1600s in a remote DC and a new issue with the configuration has come up. We have a couple of things going on and I am unsure of how to resolve the issue.



Basic configuration


VLAN1 of lies between the LTM and its upstream firewall and routes VLAN2 to the LTM.


VLAN 2 ( is routed from the FW to the LTM (so the default gw is the load balancer)


VLAN 3 ( is directly connected to the firewall.



Server A at needs to talk to a VIP at Currently, a tcpdump on the LTM itself shows the self-ip of the LTM at arp-ing for the VIP. Any traffic coming from external VLANs can go through to the VIP without issues, so I don't want to break that.



I know that I could create a forwarding VS, but I am unsure how to use that VS to only forward traffic from the subnet that is routed to the LTM to the subnet whose default gateway is on the firewall. Any help would be greatly appreciated!




2 Replies

  • Hi,



    Do you have the virtual server enabled on VLAN 3? If not, is there a reason you don't want to?



  • When you create your vserver_forward you can limit it to which vlan its exposed to.



    From your description is this correct?



    LTM intA: (VLAN1, connected to external-FW)


    LTM intB: (VLAN2, connected to internal-FW)



    then how is VLAN3 connected (since you use terms like upstream firewall, FW and then just firewall - is it three different type of firewalls connected on each interface on your LTM)?



    Could you perhaps setup a drawing of this and upload it to or such (and then put a link in here to this drawing)?