# Libpcap File Format (nanosecond-resolution) — file signature A1 B2 3C 4D (big-endian) at offset 0

For Libpcap File Format (nanosecond-resolution), hex signature is A1 B2 3C 4D (big-endian); offset is 0; extension is pcap, verified against its source on 2026-09-22.

- **Hex signature:** A1 B2 3C 4D (big-endian) _(verified: appears in the quote below)_
- **Offset:** 0 _(verified: appears in the quote below)_
- **Extension:** pcap _(verified: appears in the quote below)_
- **Format:** Libpcap File Format (nanosecond-resolution) _(verified: appears in the quote below)_

## What the source says

> 4D 3C B2 A1 (little-endian) | M<²¡ | 0 | pcap | Libpcap File Format (nanosecond-resolution) [2] | A1 B2 3C 4D (big-endian) | ¡²<M |

## Source

- https://en.wikipedia.org/wiki/List_of_file_signatures

Last verified: 2026-09-22. Review by: 2027-09-22.
Part of [File format magic numbers](https://referencesource.org/file-format-signatures/).