F5 BIG-IP LTM/DNS Regular ping loss from cisco

For traffic drop problem, you can take a packet capture concurrently on both Cisco and the BIG-IP.

From BIG-IP, you can use:

$ tcpdump -vvv -ni 0.0:nnnp -s0 host <Cisco_IP_Address> -w /var/tmp/F5_traffic_drop.pcap

From Cisco, you will need to create an access-list with the IP address you want to capture and type a couple of commands as described here: https://activereach.net/support/knowledge-base/connectivity-networking/capturing-packets-with-cisco-ios/

You can then open your capture on Wireshark. It should be enough to isolate the problem further, i.e. you will definitely see if F5 is replying to all ICMP requests, etc.

For more info about tcpdump, please refer to https://support.f5.com/csp/article/K13637