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 34The 35.Nm 36utility services Reverse ARP requests on the Ethernet connected to 37.Ar interface . 38Upon receiving a request, 39.Nm 40maps the target hardware address to an IP address via its name, which 41must be present in both the 42.Xr ethers 5 43and 44.Xr hosts 5 45databases. 46If a host does not exist in both databases, the translation cannot 47proceed and a reply will not be sent. 48.Pp 49By default, a request is honored only if the server 50(i.e., the host that 51.Nm 52is running on) 53can "boot" the target; that is, a file or directory matching the glob 54.Pa /tftpboot/\fIipaddr\fP* 55exists, where 56.Em ipaddr 57is the target IP address in hex. 58For example, the IP address 204.216.27.18 will be replied to if any of 59.Pa /tftpboot/CCD81B12 , 60.Pa /tftpboot/CCD81B12.SUN3 , 61or 62.Pa /tftpboot/CCD81B12-boot 63exist. 64This requirement can be overridden with the 65.Fl s 66flag (see below). 67.Pp 68In normal operation, 69.Nm 70forks a copy of itself and runs in the background. 71Anomalies and errors are reported via 72.Xr syslog 3 . 73.Pp 74The following options are available: 75.Bl -tag -width indent 76.It Fl a 77Listen on all the Ethernets attached to the system. 78If 79.Fl a 80is omitted, an interface must be specified. 81.It Fl d 82If 83.Fl f 84is also specified, 85.Nm 86logs messages to 87.Em stdout 88and 89.Em stderr 90instead of via 91.Xr syslog 3 . 92.It Fl f 93Run in the foreground. 94.It Fl s 95Supply a response to any RARP request for which an ethernet to IP address 96mapping exists; do not depend on the existence of 97.Pa /tftpboot/\fIipaddr\fP* . 98.It Fl t 99Supply an alternate tftp root directory to 100.Pa /tftpboot , 101similar to the 102.Fl s 103option of 104.Xr tftpd 8 . 105This permits 106.Nm 107to selectively respond to RARP requests, but use an alternate directory 108for IP checking. 109.It Fl v 110Enable verbose syslogging. 111.El 112.Sh FILES 113.Bl -tag -width /etc/ethers -compact 114.It Pa /etc/ethers 115.It Pa /etc/hosts 116.It Pa /tftpboot 117.El 118.Sh SEE ALSO 119.Xr bpf 4 120.Rs 121.%A "Finlayson, R." 122.%A "Mann, T." 123.%A "Mogul, J.C." 124.%A "Theimer, M." 125.%T "RFC 903: Reverse Address Resolution Protocol" 126.%D "June 1984" 127.%O "4 p" 128.Re 129.Sh AUTHORS 130.An -nosplit 131.An Craig Leres Aq leres@ee.lbl.gov 132and 133.An Steven McCanne Aq mccanne@ee.lbl.gov . 134Lawrence Berkeley Laboratory, University of California, Berkeley, CA. 135.Sh BUGS 136The 137.Nm 138utility can depend on the DNS to resolve the name discovered from 139.Pa /etc/ethers . 140If this name is not in the DNS but is in 141.Pa /etc/hosts , 142the DNS lookup can cause a delayed RARP response, so in this situation 143it is recommended to configure 144.Xr nsswitch.conf 5 145to read 146.Pa /etc/hosts 147first. 148