RARPD(8) BSD System Manager's Manual RARPD(8)
rarpd -- reverse ARP daemon
rarpd -a [-dfsv] [-t directory] [-P pidfile]
rarpd [-dfsv] [-t directory] [-P pidfile] interface
The rarpd utility services Reverse ARP requests on the Ethernet connected to interface.
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.
By default, a request is honored only if the server (i.e., the host that rarpd is running
on) can "boot" the target; that is, a file or directory matching the glob /tftpboot/ipaddr*
exists, where ipaddr is the target IP address in hex. For example, the IP address
126.96.36.199 will be replied to if any of /tftpboot/CCD81B12, /tftpboot/CCD81B12.SUN3, or
/tftpboot/CCD81B12-boot exist. This requirement can be overridden with the -s flag (see
In normal operation, rarpd forks a copy of itself and runs in the background. Anomalies and
errors are reported via syslog(3).
The following options are available:
-a Listen on all the Ethernets attached to the system. If -a is omitted, an interface
must be specified.
-d If -f is also specified, rarpd logs messages to stdout and stderr instead of via
-f Run in the foreground.
-P Specify the pathname of the PID file. If not specified, /var/run/rarpd.pid or
/var/run/rarpd.ifname.pid will be used depending on the -a flag or the specified
-s Supply a response to any RARP request for which an ethernet to IP address mapping
exists; do not depend on the existence of /tftpboot/ipaddr*.
-t Supply an alternate tftp root directory to /tftpboot, similar to the -s option of
tftpd(8). This permits rarpd to selectively respond to RARP requests, but use an
alternate directory for IP checking.
-v Enable verbose syslogging.
Finlayson, R., Mann, T., Mogul, J.C., and Theimer, M., RFC 903: Reverse Address Resolution
Protocol, June 1984, 4 p.
Craig Leres <firstname.lastname@example.org> and Steven McCanne <email@example.com>. Lawrence Berkeley
Laboratory, University of California, Berkeley, CA.
The rarpd utility can depend on the DNS to resolve the name discovered from /etc/ethers. If
this name is not in the DNS but is in /etc/hosts, the DNS lookup can cause a delayed RARP
response, so in this situation it is recommended to configure nsswitch.conf(5) to read
BSD July 9, 2012 BSD