---
name: "hosts.equiv"
section: "5"
platform: "macos"
package: "Libinfo"
version: "600"
release: "macOS 26.5"
platforms: ["linux", "freebsd", "macos"]
url: "https://new.carta.tech/hosts.equiv"
---

# hosts.equiv(5)

trusted remote hosts and host-user pairs

## NAME

**hosts.equiv**, **.rhosts** – trusted remote hosts and host-user pairs

## DESCRIPTION

The **hosts.equiv** and **.rhosts** files list hosts and users which are \`\`trusted'' by the local host when a connection is made via [rlogind(8)](/rlogind/8.md), [rshd(8)](/rshd/8.md), or any other server that uses [ruserok(3)](/ruserok/3.md). This mechanism bypasses password checks, and is required for access via [rsh(1)](/rsh/1.md).

Each line of these files has the format:

```
hostname [username]
```

The *hostname* may be specified as a host name (typically a fully qualified host name in a DNS environment) or address, *+@netgroup* (from which only the host names are checked), or a \`\`+'' wildcard (allow all hosts).

The *username*, if specified, may be given as a user name on the remote host, *+@netgroup* (from which only the user names are checked), or a \`\`+'' wildcard (allow all remote users).

If a *username* is specified, only that user from the specified host may login to the local machine.  If a *username* is not specified, any user may login with the same user name.

## EXAMPLES

somehost

A common usage:  users on *somehost* may login to the local host as the same user name.

somehost username

The user *username* on *somehost* may login to the local host.  If specified in */etc/hosts.equiv*, the user may login with only the same user name.

\+@anetgroup username

The user *username* may login to the local host from any machine listed in the netgroup *anetgroup*.

```
+
+ +
```

Two severe security hazards.  In the first case, allows a user on any machine to login to the local host as the same user name.  In the second case, allows any user on any machine to login to the local host (as any user, if in */etc/hosts.equiv*).

## WARNINGS

The username checks provided by this mechanism are *not* secure, as the remote user name is received by the server unchecked for validity.  Therefore this mechanism should only be used in an environment where all hosts are completely trusted.

A numeric host address instead of a host name can help security considerations somewhat; the address is then used directly by [iruserok(3)](/iruserok/3.md).

When a username (or netgroup, or +) is specified in */etc/hosts.equiv*, that user (or group of users, or all users, respectively) may login to the local host as *any* *local* *user*. Usernames in */etc/hosts.equiv* should therefore be used with extreme caution, or not at all.

A *.rhosts* file must be owned by the user whose home directory it resides in, and must be writable only by that user.

Logins as root only check root's *.rhosts* file; the */etc/hosts.equiv* file is not checked for security.  Access permitted through root's *.rhosts* file is typically only for [rsh(1)](/rsh/1.md), as root must still login on the console for an interactive login such as [rlogin(1)](/rlogin/1.md).

## FILES

- */etc/hosts.equiv*

  Global trusted host-user pairs list

- *~/.rhosts*

  Per-user trusted host-user pairs list

## SEE ALSO

[rcp(1)](/rcp/1.md), [rlogin(1)](/rlogin/1.md), [rsh(1)](/rsh/1.md), [rcmd(3)](/rcmd/3.md), [ruserok(3)](/ruserok/3.md), [netgroup(5)](/netgroup/5.md)

## HISTORY

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

## BUGS

The [ruserok(3)](/ruserok/3.md) implementation currently skips negative entries (preceded with a \`\`-'' sign) and does not treat them as \`\`short-circuit'' negative entries.