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

Forum Discussion

Alkuin_Melvin_1's avatar
Alkuin_Melvin_1
Icon for Nimbostratus rankNimbostratus
Dec 09, 2015

TCPDump for capturing traffing between Virtual Server and Pool Members

Hi guys, glad to have this community to help me.   I want to ask what is the best way to capturing traffic between my servers going to a VS and specific pool members.   For example i have one ...
application delivery
LTM
Hannes_Rapp_162's avatar
Hannes_Rapp_162
Icon for Nacreous rankNacreous
Dec 09, 2015

Problem is that for the serverside connection, the source IP is your VS IP (or SNAT IP if you use), therefore, nothing will be captured by your filter.

Why not set up two concurrent captures and later compare them side by side for the complete flow? If someone has any better ideas to get it in a single filter capture, please let me know!

tcpdump -i VLAN-EXTERNAL 'src host 172.16.16.100 and dst host 172.16.16.1' -w ext.pcap
tcpdump -i VLAN-INTERNAL 'src host 172.16.16.1 and (dst host 10.10.10.11 or dst host 10.10.10.12)' -w int.pcap
  • IRONMAN's avatar
    IRONMAN
    Icon for Cirrostratus rankCirrostratus
    Feb 13, 2019

    Are you sure , in Server Side , the Source IP for capture (172.16.16.1), which is VIP IP,without SNAT, As per me, it should be client Source IP?

     

    But i am confused. please confirm?