---
name: "protocols"
section: "5"
platform: "freebsd"
package: "base"
version: "16.0-CURRENT-20261027-61c70dc16a79"
release: "FreeBSD 16.0-CURRENT (2026-10-27)"
platforms: ["linux", "freebsd", "openbsd", "macos"]
url: "https://new.carta.tech/protocols"
---

# protocols(5)

protocol name data base

## NAME

**protocols** – protocol name data base

## DESCRIPTION

The **protocols** file contains information regarding the assigned protocol numbers used by IPv4 and IPv6 to identify the next level protocol. For each protocol a single line should be present with the following information:

```
official protocol name
protocol number
aliases
```

Items are separated by any number of blanks and/or tab characters. A \`\`#'' indicates the beginning of a comment; characters up to the end of the line are not interpreted by routines which search the file.

Protocol names may contain any printable character other than a field delimiter, newline, or comment character.

## FILES

- */etc/protocols*

  The **protocols** file resides in */etc*.

## SEE ALSO

[getprotoent(3)](/getprotoent/3.md) *IANA Allocation Guidelines For Values In the Internet Protocol and Related Headers*, RFC 2780, March 2000. *IANA Allocation Guidelines for the Protocol Field*, RFC 5237, February 2008.

## HISTORY

The **protocols** file format appeared in 4.2BSD, describing the "known protocols used in the DARPA Internet".

## BUGS

A name server should be used instead of a static file.