rarpd(8)

rarpd8

Reverse arp daemon

Usage

rarpd [-adflt] if0 [ifN]

Overview

rarpd services Reverse ARP requests on the Ethernet connected to the specified interfaces. Upon receiving a request, rarpd maps the target hardware address to an IP address via its name, which must be present in both the ethers(5) and hosts(5) databases. If a host does not exist in both databases, the translation cannot proceed and a reply will not be sent.

In normal operation, rarpd forks a copy of itself and runs in the background. Anomalies and errors are reported via syslog(3).

The options are as follows:

-a

Listen on all the Ethernets attached to the system. If -a is omitted, a list of interfaces must be specified.

-d

Run in debug mode, with all the output to stderr. This option implies the -f option.

-f

Run in the foreground.

Not on Linux.
-l

Log all requests to syslog(3).

Not on Linux, FreeBSD or macOS.
-t

Only honour a request if the server (the host that rarpd is running on) can "boot" the target; that is, if a file or directory called /tftpboot/ipaddr exists, where ipaddr is the target IP address expressed in uppercase hexadecimal (only the first 8 characters of filenames are checked).

Not on Linux or macOS.

Files

/etc/ethers

Ethernet host name database.

/etc/hosts

Host name database.

Releases

61 releases since OpenBSD 2.1; the text changed 13 times.

  1. 2.1–2.3
  2. 2.4
  3. 2.5
  4. 2.6
  5. 2.7–2.8
  6. 2.9–3.5
  7. 3.6–3.8
  8. 3.9–4.1
  9. 4.2–4.3
  10. 4.4–4.8
  11. 4.9–5.2
  12. 5.3–5.6
  13. 5.7–5.8
  14. 5.9–8.0

-l since OpenBSD 2.4; -t since OpenBSD 3.6.

Standards

R. Finlayson, T. Mann, J. Mogul, and M. Theimer, A Reverse Address Resolution Protocol, RFC 903, June 1984.

Authors

Craig Leres ⟨[email protected]⟩ and Steven McCanne ⟨[email protected]⟩, Lawrence Berkeley Laboratory, University of California, Berkeley, CA.

From man 8.0-current-20261107 in OpenBSD 8.0-current (2026-11-07). Parsed by carta from the page's mdoc source.