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omegaman66_1784's avatar
omegaman66_1784
Icon for Nimbostratus rankNimbostratus
Nov 25, 2014

Virtual IP one way

Just trying to understand the difference between Virtual IP and Nat IP

 

I have a vlan 50 that routable in my network and vlan 51 thats not

 

I create a virtual IP with vlan 50 and a node thats on vlan 51 From the node I can ping other virtual F5 vlan 50 IP on itself but cant ping any vlan 50 outside the F5

 

But if I create a NAT with inside and outside of 51/50,From the vlan 51 IP I can ping all vlan 51 IPs on the network.

 

Why is that? Is virtual IP only 1 way?

 

application delivery
big-ip virtual edition
design
LTM

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  • Andreas_Lamprec's avatar
    Andreas_Lamprec
    Icon for Nimbostratus rankNimbostratus
    Nov 26, 2014

    LTM does not forward any IP packets for traffic it is not "responsible" for. If you create a VIP on a port, LTM will forward traffic for this VIP/port to the backend servers. But any traffic from that backend servers to anywhere on the "other side" of LTM is not forwarded by default.

     

    You need to create a "Traffic forwarder" virtual server which is of type "forwarding (IP)" and reacts to 0.0.0.0/0.0.0.0 as Destination Network on "* All Ports" and for "* All Protocols". This virtual server has then be enabled on all vlans where you want the LTM to forward traffic.

     

    As a last step, you need to route your VLAN 51 network to the VLAN 50 address of LTM and also put the VLAN51 address of LTM as default gateway on the nodes in VLAN51.