-pcap Network Type 276 Unknown Or Unsupported- 📢

Standard Ethernet is type 1 (LINKTYPE_ETHERNET). So why type 276?

Modern network cards and virtualized switches (e.g., in high-frequency trading or telecom environments) can use a feature called “packet mpacket” or “multi-packet” mode. Instead of generating a separate PCAP record for every tiny 64-byte ACK packet—which wastes CPU and storage—the driver bundles several Ethernet frames into one big “super-packet.” Each bundled frame retains its original Ethernet headers, but they are packed contiguously.

When a capture tool like libpcap saves this to a file, it sets the link-layer header type to 276 so that a reader knows: “Warning: Inside this packet, there are multiple Ethernet frames. Parse them in sequence.”

Use this for a quick question in a community channel.

Subject: Issue parsing PCAP - "network type 276 unknown or unsupported" -pcap network type 276 unknown or unsupported-

Body: Hey everyone, I'm hitting a wall with a capture file. When I try to open it in Wireshark, I get the error: -pcap network type 276 unknown or unsupported-.

I believe type 276 is a specialized header (possibly related to [Infiniband/Raw IP/proprietary link]), but I can't find documentation on how to force Wireshark to interpret it.

Has anyone run into this specific type before? Is there a dd command or a wiretap setting I can use to strip the header and view the payload?

Thanks!

from scapy.all import rdpcap, wrpcap, Raw
pkts = rdpcap("in.pcap")
out = []
for p in pkts:
    b = bytes(p)[4:]
    out.append(Raw(b))
wrpcap("out.pcap", out)

To understand the error, you must understand the pcap link-layer header type (DLT, or Data Link Type). When a packet is captured, the capture tool does not just store the raw IP packets; it stores the frame exactly as it appeared on the wire (or in the host OS). The DLT value tells the reading application how to parse the first few bytes of the packet.

For example: