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

# ethers(5)

ethernet address database

## NAME

**ethers** – ethernet address database

## DESCRIPTION

The **ethers** database contains information regarding known 48-bit ethernet addresses of hosts on an Internetwork. The data is stored in a file called */etc/ethers* in the following format:

*ethernet-address* *fully-qualified-host-name*

Items are separated by any number of blanks and/or tab characters. A \`\`#'' at the start of a line indicates the beginning of a comment that extends to the end of the line. A \`\`+'' at the start of a line will cause the [ethers(3)](/ethers/3.md) library functions to use data stored in the NIS *ethers.byname* and *ethers.byaddr* maps in addition to the data in the */etc/ethers* file.

An ethernet address is expressed in ASCII form as "x:x:x:x:x:x" where *x* is a hexadecimal value between 0x00 and 0xFF. The address values should be in network order. Hostnames specified in the */etc/ethers* database should correspond to entries in the [hosts(5)](/hosts/5.md) file.

The **ether\_line**() function in the standard C library can be used to break individual lines in the */etc/ethers* database into their individual components: a binary Ethernet address stored as an *ether\_addr* structure, and a hostname stored as a character string.

## FILES

- */etc/ethers*

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

## SEE ALSO

[ethers(3)](/ethers/3.md), [yp(8)](/yp/8.md)

## HISTORY

The **ethers** format is based on the format used in SunOS 4.1.x.