1.\" Copyright (c) 1990, 1991, 1993 The Regents of the University of 2.\" California. All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that: (1) source code distributions 6.\" retain the above copyright notice and this paragraph in its entirety, (2) 7.\" distributions including binary code include the above copyright notice and 8.\" this paragraph in its entirety in the documentation or other materials 9.\" provided with the distribution. Neither the name of 10.\" the University nor the names of its contributors may be used to endorse 11.\" or promote products derived from this software without specific prior 12.\" written permission. 13.\" THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED 14.\" WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF 15.\" MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. 16.\" 17.\" $FreeBSD: src/usr.sbin/rarpd/rarpd.8,v 1.22 2005/02/09 18:04:41 ru Exp $ 18.\" $DragonFly: src/usr.sbin/rarpd/rarpd.8,v 1.2 2003/06/17 04:30:02 dillon Exp $ 19.\" 20.Dd November 16, 2001 21.Dt RARPD 8 22.Os 23.Sh NAME 24.Nm rarpd 25.Nd reverse ARP daemon 26.Sh SYNOPSIS 27.Nm 28.Fl a 29.Op Fl dfsv 30.Op Fl t Ar directory 31.Nm 32.Op Fl dfsv 33.Op Fl t Ar directory 34.Ar interface 35.Sh DESCRIPTION 36The 37.Nm 38utility services Reverse ARP requests on the Ethernet connected to 39.Ar interface . 40Upon receiving a request, 41.Nm 42maps the target hardware address to an IP address via its name, which 43must be present in both the 44.Xr ethers 5 45and 46.Xr hosts 5 47databases. 48If a host does not exist in both databases, the translation cannot 49proceed and a reply will not be sent. 50.Pp 51By default, a request is honored only if the server 52(i.e., the host that 53.Nm 54is running on) 55can "boot" the target; that is, a file or directory matching the glob 56.Pa /tftpboot/\fIipaddr\fP* 57exists, where 58.Em ipaddr 59is the target IP address in hex. 60For example, the IP address 204.216.27.18 will be replied to if any of 61.Pa /tftpboot/CCD81B12 , 62.Pa /tftpboot/CCD81B12.SUN3 , 63or 64.Pa /tftpboot/CCD81B12-boot 65exist. 66This requirement can be overridden with the 67.Fl s 68flag (see below). 69.Pp 70In normal operation, 71.Nm 72forks a copy of itself and runs in the background. 73Anomalies and errors are reported via 74.Xr syslog 3 . 75.Pp 76The following options are available: 77.Bl -tag -width indent 78.It Fl a 79Listen on all the Ethernets attached to the system. 80If 81.Fl a 82is omitted, an interface must be specified. 83.It Fl d 84If 85.Fl f 86is also specified, 87.Nm 88logs messages to 89.Em stdout 90and 91.Em stderr 92instead of via 93.Xr syslog 3 . 94.It Fl f 95Run in the foreground. 96.It Fl s 97Supply a response to any RARP request for which an ethernet to IP address 98mapping exists; do not depend on the existence of 99.Pa /tftpboot/\fIipaddr\fP* . 100.It Fl t 101Supply an alternate tftp root directory to 102.Pa /tftpboot , 103similar to the 104.Fl s 105option of 106.Xr tftpd 8 . 107This permits 108.Nm 109to selectively respond to RARP requests, but use an alternate directory 110for IP checking. 111.It Fl v 112Enable verbose syslogging. 113.El 114.Sh FILES 115.Bl -tag -width /etc/ethers -compact 116.It Pa /etc/ethers 117.It Pa /etc/hosts 118.It Pa /tftpboot 119.El 120.Sh SEE ALSO 121.Xr bpf 4 122.Rs 123.%A "Finlayson, R." 124.%A "Mann, T." 125.%A "Mogul, J.C." 126.%A "Theimer, M." 127.%T "RFC 903: Reverse Address Resolution Protocol" 128.%D "June 1984" 129.%O "4 p" 130.Re 131.Sh AUTHORS 132.An -nosplit 133.An Craig Leres Aq leres@ee.lbl.gov 134and 135.An Steven McCanne Aq mccanne@ee.lbl.gov . 136Lawrence Berkeley Laboratory, University of California, Berkeley, CA. 137.Sh BUGS 138The 139.Nm 140utility can depend on the DNS to resolve the name discovered from 141.Pa /etc/ethers . 142If this name is not in the DNS but is in 143.Pa /etc/hosts , 144the DNS lookup can cause a delayed RARP response, so in this situation 145it is recommended to configure 146.Xr nsswitch.conf 5 147to read 148.Pa /etc/hosts 149first. 150