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Nishant_374138's avatar
Nishant_374138
Icon for Nimbostratus rankNimbostratus
Oct 10, 2018

Unable to ping from F5 LTM to it's internal VLAN nodes

![Image Text] (/Portals/0/Users/122/38/374138/F5LTMSnapshot-2.jpg?ver=2018-10-10-053047-617)

 

5 Replies

  • Hamish's avatar
    Hamish
    Icon for Cirrocumulus rankCirrocumulus

    My money is on an eternal issue. All 3 hosts (1 that works, and 2 that don't) are accessed via the same network interface. The fact that 1 works indicates that there's network connectivity to the VLAN (10.2.0.0/24). However I would

     

    1. Do you get ARP responses for all 3 hosts? or just the one that works.
    2. If no arp resolution, debug that. Do you see the arp requests being sent on the right interface? Do you see the arp requests arrive at the hosts with that address? Do you see them reply? Do you see the reply get to the BigIP?

       

    3. If you get the MAC resolved (ARP works) then tcpdump the interface to prove you are sending ICMP echo-requests... Again, run through the same diags as for the arp. Do you see the traffic leave the bigIP? With the right MAC address? Do you see the echo-request arrive at the destination? Do you seethe response go back? Do all the responses (echo-response) arrive back at the BigIP on the same interface that they left from? (BigIP doesn't do async routing by default)

       

    Once you have done all that you may have a new direction to look into.

     

  • Check ARP tables... and make sure you've turned off windows firewall on the nodes, or they won't answer you via ICMP (ping). Also check subnet masks for consistency, and ensure service is running on each node & test it

     

    • Nishant_374138's avatar
      Nishant_374138
      Icon for Nimbostratus rankNimbostratus

      A very good evening..

       

      Hi DevnullNZ and Hamish,

       

      Thanks for your quick reply. Yes i am getting ARP entry of my internal VLAN nodes in ARP table.

       

      I am exiting to tell you that the issue is resolved-

       

      ICMP(ping) issue resolved after turning off windows firewall and i am also able to telnet http service after enabling http service on server.

       

      Thanks a lot.. You saved my lot of time.

       

      Thanks, Nishant

       

  • Check ARP tables... and make sure you've turned off windows firewall on the nodes, or they won't answer you via ICMP (ping). Also check subnet masks for consistency, and ensure service is running on each node & test it

     

    • Nishant_374138's avatar
      Nishant_374138
      Icon for Nimbostratus rankNimbostratus

      A very good evening..

       

      Hi DevnullNZ and Hamish,

       

      Thanks for your quick reply. Yes i am getting ARP entry of my internal VLAN nodes in ARP table.

       

      I am exiting to tell you that the issue is resolved-

       

      ICMP(ping) issue resolved after turning off windows firewall and i am also able to telnet http service after enabling http service on server.

       

      Thanks a lot.. You saved my lot of time.

       

      Thanks, Nishant