I tried these commands:
1.tcpdump -r bpf-pcap.pcapng -w op2.txt proto not dns and not tcp
2.tcpdump -r bpf-pcap.pcapng -w op2.txt proto not dns and tcp
None of these are correct. I also checked the manual page but couldn't find what's wrong.
What have I missed?
I think you want:
tcpdump -r bpf-pcap.pcapng -w op2.pcap not port 53 and not tcp
Note -w
doesn't write a text file but a binary file with the raw packets.