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. 44The data is stored in a file called 45.Pa /etc/ethers 46in the following format: 47.Bd -unfilled -offset indent 48.Pa ethernet-address fully-qualified-host-name 49.Ed 50.Pp 51Items are separated by any number of blanks and/or 52tab characters. 53A ``#'' at the start of a line indicates the 54beginning of a comment that extends to the end of the line. 55A ``+'' at 56the start of a line will cause the 57.Xr ethers 3 58library functions to use data stored in the 59.Xr NIS 4 60.Pa ethers.byname 61and 62.Pa ethers.byaddr 63maps in addition to the data in the 64.Pa /etc/ethers 65file. 66.Pp 67An ethernet address is expressed in 68.Tn ASCII 69form as "x:x:x:x:x:x" where 70.Ar x 71is a hexadecimal value between 0x00 and 0xFF. 72The address values 73should be in network order. 74Hostnames specified in the 75.Pa /etc/ethers 76database should correspond to entries in the 77.Xr hosts 5 78file. 79.Pp 80The 81.Fn ether_line 82function in the standard C library can be used to break individual 83lines in the 84.Pa /etc/ethers 85database into their individual components: a binary Ethernet address 86stored as an 87.Pa ether_addr 88structure, and a hostname stored as a character string. 89.Sh FILES 90.Bl -tag -width /etc/services -compact 91.It Pa /etc/ethers 92The 93.Nm ethers 94file resides in 95.Pa /etc . 96.El 97.Sh SEE ALSO 98.Xr ethers 3 , 99.Xr yp 4 100.Sh HISTORY 101The 102.Nm ethers 103format is based on the format used in SunOS 4.1.x. 104