RARPD(8) BSD System Manager's Manual RARPD(8)NAMErarpd — reverse ARP daemon
SYNOPSISrarpd-a [-dfsv] [-t directory]
rarpd [-dfsv] [-t directory] 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 data‐
bases, 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 18.104.22.168 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 below).
In normal operation, rarpd forks a copy of itself and runs in the back‐
ground. 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 syslog(3).
-f Run in the foreground.
-s Supply a response to any RARP request for which an ethernet to IP
address mapping exists; do not depend on the existence of
-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
-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 /etc/hosts first.
BSD November 16, 2001 BSD