For more information regarding the security incident at F5, the actions we are taking to address it, and our ongoing efforts to protect our customers, click here.

Forum Discussion

spalande's avatar
spalande
Icon for Nacreous rankNacreous
Sep 15, 2014

webserver (client) unable to reach DNS

we have an issue where web servers (vlan40) are unable to reach DNS. for servers F5 is the gateway. Can see DNS traffic coming in but no DNS response. Fw which is next hop is unable to see DNS traffic.

 

Checked everything - portchannel (vlan40, int 1.3) is up - we have wildcard performance layer4 VS configured enabled on vlan40 configured - able to reach DNS from load balancer - Can see DNS response coming in for hosts in another vlan.

 

Please guide what should be next troubleshooting steps Thanks

 

design

2 Replies

  • boneyard's avatar
    boneyard
    Icon for MVP rankMVP
    Sep 15, 2014

    if you have a setup on another VLAN behind the BIG-IP that does work i would compare configs to spot the difference.

     

    is your wildcard performance virtual server configured to handle TCP and UDP?

     

    why don't use an IP forwarding virtual server for this?

     

  • spalande's avatar
    spalande
    Icon for Nacreous rankNacreous
    Sep 15, 2014

    I think next step, i can try creating specific IP forwarding virtual server for DNS servers on port 53...