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.\" $FreeBSD$ 18.\" 19.Dd November 16, 2001 20.Dt RARPD 8 21.Os 22.Sh NAME 23.Nm rarpd 24.Nd reverse ARP daemon 25.Sh SYNOPSIS 26.Nm 27.Fl a 28.Op Fl dfsv 29.Op Fl t Ar directory 30.Nm 31.Op Fl dfsv 32.Op Fl t Ar directory 33.Ar interface 34.Sh DESCRIPTION 35The 36.Nm 37utility services Reverse ARP requests on the Ethernet connected to 38.Ar interface . 39Upon receiving a request, 40.Nm 41maps the target hardware address to an IP address via its name, which 42must be present in both the 43.Xr ethers 5 44and 45.Xr hosts 5 46databases. 47If a host does not exist in both databases, the translation cannot 48proceed and a reply will not be sent. 49.Pp 50By default, a request is honored only if the server 51(i.e., the host that 52.Nm 53is running on) 54can "boot" the target; that is, a file or directory matching the glob 55.Pa /tftpboot/\fIipaddr\fP* 56exists, where 57.Em ipaddr 58is the target IP address in hex. 59For example, the IP address 204.216.27.18 will be replied to if any of 60.Pa /tftpboot/CCD81B12 , 61.Pa /tftpboot/CCD81B12.SUN3 , 62or 63.Pa /tftpboot/CCD81B12-boot 64exist. 65This requirement can be overridden with the 66.Fl s 67flag (see below). 68.Pp 69In normal operation, 70.Nm 71forks a copy of itself and runs in the background. 72Anomalies and errors are reported via 73.Xr syslog 3 . 74.Pp 75The following options are available: 76.Bl -tag -width indent 77.It Fl a 78Listen on all the Ethernets attached to the system. 79If 80.Fl a 81is omitted, an interface must be specified. 82.It Fl d 83If 84.Fl f 85is also specified, 86.Nm 87logs messages to 88.Em stdout 89and 90.Em stderr 91instead of via 92.Xr syslog 3 . 93.It Fl f 94Run in the foreground. 95.It Fl s 96Supply a response to any RARP request for which an ethernet to IP address 97mapping exists; do not depend on the existence of 98.Pa /tftpboot/\fIipaddr\fP* . 99.It Fl t 100Supply an alternate tftp root directory to 101.Pa /tftpboot , 102similar to the 103.Fl s 104option of 105.Xr tftpd 8 . 106This permits 107.Nm 108to selectively respond to RARP requests, but use an alternate directory 109for IP checking. 110.It Fl v 111Enable verbose syslogging. 112.El 113.Sh FILES 114.Bl -tag -width /etc/ethers -compact 115.It Pa /etc/ethers 116.It Pa /etc/hosts 117.It Pa /tftpboot 118.El 119.Sh SEE ALSO 120.Xr bpf 4 121.Rs 122.%A "Finlayson, R." 123.%A "Mann, T." 124.%A "Mogul, J.C." 125.%A "Theimer, M." 126.%T "RFC 903: Reverse Address Resolution Protocol" 127.%D "June 1984" 128.%O "4 p" 129.Re 130.Sh AUTHORS 131.An -nosplit 132.An Craig Leres Aq leres@ee.lbl.gov 133and 134.An Steven McCanne Aq mccanne@ee.lbl.gov . 135Lawrence Berkeley Laboratory, University of California, Berkeley, CA. 136.Sh BUGS 137The 138.Nm 139utility can depend on the DNS to resolve the name discovered from 140.Pa /etc/ethers . 141If this name is not in the DNS but is in 142.Pa /etc/hosts , 143the DNS lookup can cause a delayed RARP response, so in this situation 144it is recommended to configure 145.Xr nsswitch.conf 5 146to read 147.Pa /etc/hosts 148first. 149