1.\" Copyright (c) 1995 2.\" Bill Paul <wpaul@ctr.columbia.edu>. All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 3. All advertising materials mentioning features or use of this software 13.\" must display the following acknowledgement: 14.\" This product includes software developed by Bill Paul. 15.\" 4. Neither the name of the author nor the names of any co-contributors 16.\" may be used to endorse or promote products derived from this software 17.\" without specific prior written permission. 18.\" 19.\" THIS SOFTWARE IS PROVIDED BY Bill Paul AND CONTRIBUTORS ``AS IS'' AND 20.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 23.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29.\" SUCH DAMAGE. 30.\" 31.\" $FreeBSD$ 32.\" 33.Dd April 12, 1995 34.Dt ETHERS 5 35.Os FreeBSD 2.1 36.Sh NAME 37.Nm ethers 38.Nd ethernet address database 39.Sh DESCRIPTION 40The 41.Nm ethers 42database contains information regarding known 48-bit ethernet addresses 43of hosts on an Internetwork. The data is stored in a file called 44.Pa /etc/ethers 45in the following format: 46.Bd -unfilled -offset indent 47.Pa ethernet-address fully-qualified-host-name 48.Ed 49.Pp 50Items are separated by any number of blanks and/or 51tab characters. A ``#'' at the start of a line indicates the 52beginning of a comment that extends to the end of the line. A ``+'' at 53the start of a line will cause the 54.Xr ethers 3 55library functions to use data stored in the 56.Xr NIS 4 57.Pa ethers.byname 58and 59.Pa ethers.byaddr 60maps in addition to the data in the 61.Pa /etc/ethers 62file. 63.Pp 64An ethernet address is expressed in 65.Tn ASCII 66form as "x:x:x:x:x:x" where 67.Ar x 68is a hexadecimal value between 0x00 and 0xFF. The address values 69should be in network order. Hostnames specified in the 70.Pa /etc/ethers 71database should correspond to entries in the 72.Xr hosts 5 73file. 74.Pp 75The 76.Fn ether_line 77function in the standard C library can be used to break individual 78lines in the 79.Pa /etc/ethers 80database into their individual components: a binary Ethernet address 81stored as an 82.Pa ether_addr 83structure, and a hostname stored as a character string. 84.Sh FILES 85.Bl -tag -width /etc/services -compact 86.It Pa /etc/ethers 87The 88.Nm ethers 89file resides in 90.Pa /etc . 91.El 92.Sh SEE ALSO 93.Xr ethers 3 , 94.Xr yp 4 95.Sh HISTORY 96The 97.Nm ethers 98format is based on the format used in SunOS 4.1.x. 99