---
name: "hosts"
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/hosts"
---

# hosts(5)

host name data base

## NAME

**hosts** – host name data base

## DESCRIPTION

The **hosts** file contains information regarding the known hosts on the network. It can be used in conjunction with DNS, and the NIS maps \`hosts.byaddr' and \`hosts.byname', as controlled by [nsswitch.conf(5)](/nsswitch.conf/5.md). For each host a single line should be present with the following information:

```
Internet address
official host name
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.

This file provides a backup used when the name server is not running. For the name server, it is suggested that only a few addresses be included in this file. These include addresses for the local interfaces that [ifconfig(8)](/ifconfig/8.md) needs at boot time and a few machines on the local network.

Network addresses are specified in either the conventional \`\`.'' (dot) notation for IPv4 or colon hexadecimal notation for IPv6, as understood by the [inet\_pton(3)](/inet_pton/3.md) routine from the Internet address manipulation library, [inet(3)](/inet/3.md). Host names may contain any printable character other than a field delimiter, newline, or comment character.

## FILES

- */etc/hosts*

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

## SEE ALSO

[gethostbyname(3)](/gethostbyname/3.md), [inet(3)](/inet/3.md), [nsswitch.conf(5)](/nsswitch.conf/5.md), [ifconfig(8)](/ifconfig/8.md)

## HISTORY

The **hosts** file format appeared in 4.1cBSD.