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.Fl a 31.Op Fl dfsv 32.Op Fl t Ar directory 33.Nm 34.Op Fl dfsv 35.Op Fl t Ar directory 36.Ar interface 37.Sh DESCRIPTION 38The 39.Nm 40utility services Reverse ARP requests on the Ethernet connected to 41.Ar interface . 42Upon receiving a request, 43.Nm 44maps the target hardware address to an IP address via its name, which 45must be present in both the 46.Xr ethers 5 47and 48.Xr hosts 5 49databases. 50If a host does not exist in both databases, the translation cannot 51proceed and a reply will not be sent. 52.Pp 53By default, a request is honored only if the server 54(i.e., the host that 55.Nm 56is running on) 57can "boot" the target; that is, a file or directory matching the glob 58.Pa /tftpboot/\fIipaddr\fP* 59exists, where 60.Em ipaddr 61is the target IP address in hex. 62For example, the IP address 204.216.27.18 will be replied to if any of 63.Pa /tftpboot/CCD81B12 , 64.Pa /tftpboot/CCD81B12.SUN3 , 65or 66.Pa /tftpboot/CCD81B12-boot 67exist. 68This requirement can be overridden with the 69.Fl s 70flag (see below). 71.Pp 72In normal operation, 73.Nm 74forks a copy of itself and runs in the background. 75Anomalies and errors are reported via 76.Xr syslog 3 . 77.Pp 78The following options are available: 79.Bl -tag -width indent 80.It Fl a 81Listen on all the Ethernets attached to the system. 82If 83.Fl a 84is omitted, an interface must be specified. 85.It Fl d 86If 87.Fl f 88is also specified, 89.Nm 90logs messages to 91.Em stdout 92and 93.Em stderr 94instead of via 95.Xr syslog 3 . 96.It Fl f 97Run in the foreground. 98.It Fl s 99Supply a response to any RARP request for which an ethernet to IP address 100mapping exists; do not depend on the existence of 101.Pa /tftpboot/\fIipaddr\fP* . 102.It Fl t 103Supply an alternate tftp root directory to 104.Pa /tftpboot , 105similar to the 106.Fl s 107option of 108.Xr tftpd 8 . 109This permits 110.Nm 111to selectively respond to RARP requests, but use an alternate directory 112for IP checking. 113.It Fl v 114Enable verbose syslogging. 115.El 116.Sh FILES 117.Bl -tag -width /etc/ethers -compact 118.It Pa /etc/ethers 119.It Pa /etc/hosts 120.It Pa /tftpboot 121.El 122.Sh SEE ALSO 123.Xr bpf 4 124.Rs 125.%A "Finlayson, R." 126.%A "Mann, T." 127.%A "Mogul, J.C." 128.%A "Theimer, M." 129.%T "RFC 903: Reverse Address Resolution Protocol" 130.%D "June 1984" 131.%O "4 p" 132.Re 133.Sh AUTHORS 134.An -nosplit 135.An Craig Leres Aq leres@ee.lbl.gov 136and 137.An Steven McCanne Aq mccanne@ee.lbl.gov . 138Lawrence Berkeley Laboratory, University of California, Berkeley, CA. 139.Sh BUGS 140The 141.Nm 142utility can depend on the DNS to resolve the name discovered from 143.Pa /etc/ethers . 144If this name is not in the DNS but is in 145.Pa /etc/hosts , 146the DNS lookup can cause a delayed RARP response, so in this situation 147it is recommended to configure 148.Xr nsswitch.conf 5 149to read 150.Pa /etc/hosts 151first. 152