---
name: "hosts"
section: "5"
platform: "macos"
package: "files"
version: "974.120.2"
release: "macOS 26.5"
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. 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.

Network addresses may either be specified for IP version 4 or version 6. IP version 4 addresses are specified in the conventional dotted address notation. IP version 6 addresses are specified using the colon-separated notation described in RFC1924.

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

The **hosts** file is read by [mDNSResponder(8)](/mDNSResponder/8.md) and used to supply results for calls to [getaddrinfo(3)](/getaddrinfo/3.md), [getnameinfo(3)](/getnameinfo/3.md), etc. in addition to results obtained from multicast and unicast DNS.

## FILES

- */etc/hosts*

  ## SEE ALSO

[gethostent(3)](/gethostent/3.md), [getipnodebyname(3)](/getipnodebyname/3.md), [getaddrinfo(3)](/getaddrinfo/3.md), [getnameinfo(3)](/getnameinfo/3.md) *RFC1924: A Compact Representation of IPv6 Addresses*.

## HISTORY

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