With version 5.2 and later, the old tcpdump configuration method is obsolete. The source filename is automatically generated, and the destination protocol, server and desination filename are specified when copying the tcpdump. Below lists a sample capture.
Changing Encapsulation on Interfaces with Packet Capture Configured Before modifying the encapsulation on a device interface that is configured for packet capture, you must disable packet capture and rename the latest packet capture file. Otherwise, packet capture saves the packets with different encapsulations in the same packet capture file. Packet files containing packets with different encapsulations are not useful, because packet analyzer tools like tcpdump cannot analyze such files.