Mar 27, 2026 - For details about updated CVE-2025-53521 (BIG-IP APM vulnerability), refer to K000156741.

Forum Discussion

Jonathan0410's avatar
Jonathan0410
Icon for Nimbostratus rankNimbostratus
Jan 28, 2020

Troubleshooting connections to a node

Hi, I have a virtual server that a number of hosts connect to and can work successfully all day, however, there is one particular host that fails to connect.   From the CLI I can validate the w...
application delivery
LTM
TMOS
cjunior's avatar
cjunior
Icon for Nacreous rankNacreous
Jan 28, 2020

Sorry for my question,

As you are looking on network layer, have you tried to capture and see this traffic in the tcpdump utility?

Regards.

  • Jonathan0410's avatar
    Jonathan0410
    Icon for Nimbostratus rankNimbostratus
    Jan 28, 2020

    Hi and thanks for your reply. Yes I used the tcpdump utility, however, it displayed nothing on screen. I just ran tcpdump host <IP address> From the cli.

    • cjunior's avatar
      cjunior
      Icon for Nacreous rankNacreous
      Jan 28, 2020

      I'm little confused now.

      You couldn't see the client IP reaching VS address on any interface?

      You should check current status and access permissions, vlan, etc to the specific client and node.

       

      Anyway, this tcpdump may work to you see both client and server side communication filtering only by client IP:

       

      tcpdump -vni 0.0:nnnp -s0 host <CLIENT IP>

       

      I hope it helps.