The error message "pcap: network type 276 unknown or unsupported"
The pcap file format contains a 16-bit field, known as the "linktype" or "network type", which identifies the type of network traffic being captured. This field is used by pcap readers to determine how to interpret the captured packets. The linktype field is usually set to one of the well-known values defined by the pcap library, such as Ethernet (1), IP (12), or Wi-Fi (802.11) (105). -pcap network type 276 unknown or unsupported-
Recompile and install libpcap. This is overkill for most users. The error message "pcap: network type 276 unknown
For Scapy (Python):
Update Scapy and ensure it links to a modern libpcap: such as Ethernet (1)