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: src/share/man/man5/ethers.5,v 1.8.2.4 2002/02/01 15:51:18 ru Exp $ 32.\" $DragonFly: src/share/man/man5/ethers.5,v 1.2 2003/06/17 04:37:00 dillon Exp $ 33.\" 34.Dd April 12, 1995 35.Dt ETHERS 5 36.Os 37.Sh NAME 38.Nm ethers 39.Nd ethernet address database 40.Sh DESCRIPTION 41The 42.Nm 43database contains information regarding known 48-bit ethernet addresses 44of hosts on an Internetwork. 45The data is stored in a file called 46.Pa /etc/ethers 47in the following format: 48.Bd -unfilled -offset indent 49.Pa ethernet-address fully-qualified-host-name 50.Ed 51.Pp 52Items are separated by any number of blanks and/or 53tab characters. 54A ``#'' at the start of a line indicates the 55beginning of a comment that extends to the end of the line. 56A ``+'' at 57the start of a line will cause the 58.Xr ethers 3 59library functions to use data stored in the 60.Xr NIS 4 61.Pa ethers.byname 62and 63.Pa ethers.byaddr 64maps in addition to the data in the 65.Pa /etc/ethers 66file. 67.Pp 68An ethernet address is expressed in 69.Tn ASCII 70form as "x:x:x:x:x:x" where 71.Ar x 72is a hexadecimal value between 0x00 and 0xFF. 73The address values 74should be in network order. 75Hostnames specified in the 76.Pa /etc/ethers 77database should correspond to entries in the 78.Xr hosts 5 79file. 80.Pp 81The 82.Fn ether_line 83function in the standard C library can be used to break individual 84lines in the 85.Pa /etc/ethers 86database into their individual components: a binary Ethernet address 87stored as an 88.Pa ether_addr 89structure, and a hostname stored as a character string. 90.Sh FILES 91.Bl -tag -width /etc/services -compact 92.It Pa /etc/ethers 93The 94.Nm 95file resides in 96.Pa /etc . 97.El 98.Sh SEE ALSO 99.Xr ethers 3 , 100.Xr yp 8 101.Sh HISTORY 102The 103.Nm 104format is based on the format used in SunOS 4.1.x. 105