ethers(5)

ethers5

Ethernet host name database

Overview

The ethers file maps Ethernet addresses to host names. Lines consist of an address and a host name, 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.

Ethernet addresses are expressed as six hexadecimal numbers separated by colons. The functions described in ether_aton(3) can read and produce this format.

Files

/etc/ethers

Releases

61 releases since OpenBSD 2.1; the text changed 12 times.

  1. 2.1–2.2
  2. 2.3
  3. 2.4
  4. 2.5
  5. 2.6
  6. 2.7
  7. 2.8
  8. 2.9–3.3
  9. 3.4
  10. 3.5–4.1
  11. 4.2–6.4
  12. 6.5
  13. 6.6–8.0

History

The ethers file format was adopted from SunOS and appeared in NetBSD 0.9b.

Bugs

A name server should be used instead of a static file.

Lines in /etc/ethers are limited to BUFSIZ characters (currently 1024). Longer lines will be ignored.

From man 8.0-current-20261101 in OpenBSD 8.0-current (2026-11-01). Parsed by carta from the page's mdoc source.