xref: /freebsd/usr.sbin/rarpd/rarpd.8 (revision b7e469ad1099b9c91f5285c8666e8f37c30003c6)

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.Dd July 19, 1993
.Dt RARPD 8
.Os
.Sh NAME
.Nm rarpd
.Nd reverse ARP daemon
.Sh SYNOPSIS
.Nm rarpd
.Op Fl afsv
.Op Ar interface
.Sh DESCRIPTION
.Nm Rarpd
services Reverse ARP requests on the Ethernet connected to
.Ar interface .
Upon receiving a request,
.Nm
maps the target hardware address to an IP address via its name, which
must be present in both the
.Xr ethers 5
and
.Xr 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
.Nm
is running on)
can "boot" the target; that is, a file or directory matching the glob
.Pa /tftpboot/\fIipaddr\fP*
exists, where
.Em ipaddr
is the target IP address in hex.
For example, the IP address 204.216.27.18 will be replied to if any of
.Pa /tftpboot/CCD81B12 ,
.Pa /tftpboot/CCD81B12.SUN3 ,
or
.Pa /tftpboot/CCD81B12-boot
exist.
This requirement can be overridden with the
.Fl s
flag (see below).

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

.Pp
The following options are available:
.Bl -tag -width indent
.It Fl a
Listen on all the Ethernets attached to the system.
If
.Fl a
is omitted, an interface must be specified.
.It Fl f
Run in the foreground.
.It Fl s
Supply a response to any RARP request for which an ethernet to IP address
mapping exists; do not depend on the existence of
.Pa /tftpboot/\fIipaddr\fP* .
.It Fl v
Enable verbose sysloging.
.El
.Sh FILES
.Bl -tag -width /etc/ethers -compact
.It Pa /etc/ethers
.It Pa /etc/hosts
.It Pa /tftpboot
.El
.Sh SEE ALSO
.Xr bpf 4
.Pp
RFC 903: Finlayson, R.; Mann, T.; Mogul, J.C.; Theimer, M.  Reverse Address
Resolution Protocol.  1984 June; 4 p.
.Sh AUTHORS
.An Craig Leres Aq leres@ee.lbl.gov
and
.An Steven McCanne Aq mccanne@ee.lbl.gov .
Lawrence Berkeley Laboratory, University of California, Berkeley, CA.
.Sh BUGS
.Nm Rarpd
can depend on the DNS to resolve the name discovered from
.Pa /etc/ethers .
If this name is not in the DNS but is in
.Pa /etc/hosts ,
the DNS lookup
can cause a delayed RARP response, so in this situation it is reccommended to
configure
.Pa /etc/host.conf
to read
.Pa /etc/hosts
first.