VLAN Filters

The DNCA automatically configures its listen filters to allow 802.1q VLAN packets to be captured without explicit configuration.

Note: Exception: When you use port range filters, VLAN traffic is not captured.

If you are using tcpdump for traffic analysis, you must manually apply the VLAN filter tags at the command line to see VLAN packets. In the previous section, the command to start tcpdump must be augmented to enable VLAN packet capture in the following manner:

Note: Remove the slashes at the end of each line, which indicate line continuation.

tcpdump -n -i eth0 "((host 127.0.0.1 and port 80) or \
(host 172.16.0.1 and port 1) or (host 172.16.0.2 and port 2) or \
(vlan and host 127.0.0.1 and port 80) or \
(vlan and host 172.16.0.1 and port 1) or (vlan and host 172.16.0.2 and \
port 2))"