---
name: "protocols"
section: "5"
platform: "macos"
package: "files"
version: "974.120.2"
release: "macOS 26.5"
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 known protocols used in the DARPA Internet.  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.

## INTERACTION WITH DIRECTORY SERVICES

Processes generally find protocol records using one of the [getprotoent(3)](/getprotoent/3.md) family of functions. On Mac OS X, these functions interact with the DirectoryService(8) daemon, which reads the /etc/protocols file as well as searching other directory information services to determine protocol name and number information.

## FILES

- */etc/protocols*

  ## SEE ALSO

[getprotoent(3)](/getprotoent/3.md), DirectoryService(8)

## HISTORY

The **protocols** file format appeared in 4.2BSD.