1.\" @(#) $FreeBSD$ (LBL) 2.\" 3.\" Copyright (c) 1990, 1991, 1993 The Regents of the University of 4.\" California. All rights reserved. 5.\" 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that: (1) source code distributions 8.\" retain the above copyright notice and this paragraph in its entirety, (2) 9.\" distributions including binary code include the above copyright notice and 10.\" this paragraph in its entirety in the documentation or other materials 11.\" provided with the distribution, and (3) all advertising materials mentioning 12.\" features or use of this software display the following acknowledgement: 13.\" ``This product includes software developed by the University of California, 14.\" Lawrence Berkeley Laboratory and its contributors.'' Neither the name of 15.\" the University nor the names of its contributors may be used to endorse 16.\" or promote products derived from this software without specific prior 17.\" written permission. 18.\" THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED 19.\" WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF 20.\" MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. 21.\" 22.Dd November 16, 2001 23.Dt RARPD 8 24.Os 25.Sh NAME 26.Nm rarpd 27.Nd reverse ARP daemon 28.Sh SYNOPSIS 29.Nm 30.Op Fl adfsv 31.Op Fl t Ar directory 32.Op Ar interface 33.Sh DESCRIPTION 34.Nm 35services Reverse ARP requests on the Ethernet connected to 36.Ar interface . 37Upon receiving a request, 38.Nm 39maps the target hardware address to an IP address via its name, which 40must be present in both the 41.Xr ethers 5 42and 43.Xr hosts 5 44databases. 45If a host does not exist in both databases, the translation cannot 46proceed and a reply will not be sent. 47.Pp 48By default, a request is honored only if the server 49(i.e., the host that 50.Nm 51is running on) 52can "boot" the target; that is, a file or directory matching the glob 53.Pa /tftpboot/\fIipaddr\fP* 54exists, where 55.Em ipaddr 56is the target IP address in hex. 57For example, the IP address 204.216.27.18 will be replied to if any of 58.Pa /tftpboot/CCD81B12 , 59.Pa /tftpboot/CCD81B12.SUN3 , 60or 61.Pa /tftpboot/CCD81B12-boot 62exist. 63This requirement can be overridden with the 64.Fl s 65flag (see below). 66.Pp 67In normal operation, 68.Nm 69forks a copy of itself and runs in the background. 70Anomalies and errors are reported via 71.Xr syslog 3 . 72.Pp 73The following options are available: 74.Bl -tag -width indent 75.It Fl a 76Listen on all the Ethernets attached to the system. 77If 78.Fl a 79is omitted, an interface must be specified. 80.It Fl d 81If 82.Fl f 83is also specified, 84.Nm 85logs messages to 86.Em stdout 87and 88.Em stderr 89instead of via 90.Xr syslog 3 . 91.It Fl f 92Run in the foreground. 93.It Fl s 94Supply a response to any RARP request for which an ethernet to IP address 95mapping exists; do not depend on the existence of 96.Pa /tftpboot/\fIipaddr\fP* . 97.It Fl t 98Supply an alternate tftp root directory to 99.Pa /tftpboot , 100similar to the 101.Fl s 102option of 103.Xr tftpd 8 . 104This permits 105.Nm 106to selectively respond to RARP requests, but use an alternate directory 107for IP checking. 108.It Fl v 109Enable verbose syslogging. 110.El 111.Sh FILES 112.Bl -tag -width /etc/ethers -compact 113.It Pa /etc/ethers 114.It Pa /etc/hosts 115.It Pa /tftpboot 116.El 117.Sh SEE ALSO 118.Xr bpf 4 119.Rs 120.%A "Finlayson, R." 121.%A "Mann, T." 122.%A "Mogul, J.C." 123.%A "Theimer, M." 124.%T "RFC 903: Reverse Address Resolution Protocol" 125.%D "June 1984" 126.%O "4 p" 127.Re 128.Sh AUTHORS 129.An -nosplit 130.An Craig Leres Aq leres@ee.lbl.gov 131and 132.An Steven McCanne Aq mccanne@ee.lbl.gov . 133Lawrence Berkeley Laboratory, University of California, Berkeley, CA. 134.Sh BUGS 135.Nm 136can depend on the DNS to resolve the name discovered from 137.Pa /etc/ethers . 138If this name is not in the DNS but is in 139.Pa /etc/hosts , 140the DNS lookup can cause a delayed RARP response, so in this situation 141it is recommended to configure 142.Xr nsswitch.conf 5 143to read 144.Pa /etc/hosts 145first. 146