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.Dd April 12, 1995 32.Dt ETHERS 5 33.Os 34.Sh NAME 35.Nm ethers 36.Nd ethernet address database 37.Sh DESCRIPTION 38The 39.Nm 40database contains information regarding known 48-bit ethernet addresses 41of hosts on an Internetwork. 42The data is stored in a file called 43.Pa /etc/ethers 44in the following format: 45.Pp 46.D1 Ar ethernet-address fully-qualified-host-name 47.Pp 48Items are separated by any number of blanks and/or 49tab characters. 50A ``#'' at the start of a line indicates the 51beginning of a comment that extends to the end of the line. 52A ``+'' at 53the start of a line will cause the 54.Xr ethers 3 55library functions to use data stored in the 56.Tn NIS 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. 69The address values 70should be in network order. 71Hostnames specified in the 72.Pa /etc/ethers 73database should correspond to entries in the 74.Xr hosts 5 75file. 76.Pp 77The 78.Fn ether_line 79function in the standard C library can be used to break individual 80lines in the 81.Pa /etc/ethers 82database into their individual components: a binary Ethernet address 83stored as an 84.Pa ether_addr 85structure, and a hostname stored as a character string. 86.Sh FILES 87.Bl -tag -width /etc/services -compact 88.It Pa /etc/ethers 89The 90.Nm 91file resides in 92.Pa /etc . 93.El 94.Sh SEE ALSO 95.Xr ethers 3 , 96.Xr yp 8 97.Sh HISTORY 98The 99.Nm 100format is based on the format used in SunOS 4.1.x. 101