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 July 9, 2012 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.Op Fl P Ar pidfile 31.Nm 32.Op Fl dfsv 33.Op Fl t Ar directory 34.Op Fl P Ar pidfile 35.Ar interface 36.Sh DESCRIPTION 37The 38.Nm 39utility services Reverse ARP requests on the Ethernet connected to 40.Ar interface . 41Upon receiving a request, 42.Nm 43maps the target hardware address to an IP address via its name, which 44must be present in both the 45.Xr ethers 5 46and 47.Xr hosts 5 48databases. 49If a host does not exist in both databases, the translation cannot 50proceed and a reply will not be sent. 51.Pp 52By default, a request is honored only if the server 53(i.e., the host that 54.Nm 55is running on) 56can "boot" the target; that is, a file or directory matching the glob 57.Pa /tftpboot/\fIipaddr\fP* 58exists, where 59.Em ipaddr 60is the target IP address in hex. 61For example, the IP address 204.216.27.18 will be replied to if any of 62.Pa /tftpboot/CCD81B12 , 63.Pa /tftpboot/CCD81B12.SUN3 , 64or 65.Pa /tftpboot/CCD81B12-boot 66exist. 67This requirement can be overridden with the 68.Fl s 69flag (see below). 70.Pp 71In normal operation, 72.Nm 73forks a copy of itself and runs in the background. 74Anomalies and errors are reported via 75.Xr syslog 3 . 76.Pp 77The following options are available: 78.Bl -tag -width indent 79.It Fl a 80Listen on all the Ethernets attached to the system. 81If 82.Fl a 83is omitted, an interface must be specified. 84.It Fl d 85If 86.Fl f 87is also specified, 88.Nm 89logs messages to 90.Em stdout 91and 92.Em stderr 93instead of via 94.Xr syslog 3 . 95.It Fl f 96Run in the foreground. 97.It Fl P 98Specify the pathname of the PID file. 99If not specified, 100.Pa /var/run/rarpd.pid 101or 102.Pa /var/run/rarpd.ifname.pid 103will be used depending on the 104.Fl a 105flag or the specified interface name. 106.It Fl s 107Supply a response to any RARP request for which an ethernet to IP address 108mapping exists; do not depend on the existence of 109.Pa /tftpboot/\fIipaddr\fP* . 110.It Fl t 111Supply an alternate tftp root directory to 112.Pa /tftpboot , 113similar to the 114.Fl s 115option of 116.Xr tftpd 8 . 117This permits 118.Nm 119to selectively respond to RARP requests, but use an alternate directory 120for IP checking. 121.It Fl v 122Enable verbose syslogging. 123.El 124.Sh FILES 125.Bl -tag -width /etc/ethers -compact 126.It Pa /etc/ethers 127.It Pa /etc/hosts 128.It Pa /tftpboot 129.It Pa /var/run/rarpd.pid 130.El 131.Sh SEE ALSO 132.Xr bpf 4 133.Rs 134.%A "Finlayson, R." 135.%A "Mann, T." 136.%A "Mogul, J.C." 137.%A "Theimer, M." 138.%T "RFC 903: Reverse Address Resolution Protocol" 139.%D "June 1984" 140.%O "4 p" 141.Re 142.Sh AUTHORS 143.An -nosplit 144.An Craig Leres Aq leres@ee.lbl.gov 145and 146.An Steven McCanne Aq mccanne@ee.lbl.gov . 147Lawrence Berkeley Laboratory, University of California, Berkeley, CA. 148.Sh BUGS 149The 150.Nm 151utility can depend on the DNS to resolve the name discovered from 152.Pa /etc/ethers . 153If this name is not in the DNS but is in 154.Pa /etc/hosts , 155the DNS lookup can cause a delayed RARP response, so in this situation 156it is recommended to configure 157.Xr nsswitch.conf 5 158to read 159.Pa /etc/hosts 160first. 161