tcpdump - shows VLAN tag, but filtering doesn't work?
Solution 1:
Probably your tcpdump version is too old, this should work starting from tcpdump 4.9.2 / libcap 1.5.3.
tcpdump -i em2 -n -e '(vlan 2002)'
works with these versions on a RHEL 7 system (loads of stuff output ...)