Tcpdump Packet Capture

Packet capture applications such as tcpdump can be useful to:

• Identify if any PTP messages are actually being received on the PTP interface.
• Identify if messages reported missing by sfptpd are actually being received at the PTP interface.
• To inspect individual fields in PTP messages.

The following example shows how to use tcpdump to capture only PTP traffic.

# tcpdump -i <interface> dst port 319 or dst port 320 [-w <filename.pcap>]

where the <interface> is the network adapter interface being used by sfptpd.

Keep pcap files as small as possible, but large enough to capture an instance of the issue sfptpd is experiencing.