ethers - Database that maps Ethernet addresses to hostnames
The /etc/ethers file is used in conjunction with the reverse address resolution protocol daemon (rarpd) to map Ethernet addresses to hostnames. It contains information about the known (48-bit) Ethernet addresses of hosts on the Internet.
For each host on an Ethernet, a single line should be present in the file with the following information:
Items are separated by one or more spaces or tabs. A number sign (#) indicates the beginning of a comment that extends to the end of line.
The standard form for Ethernet addresses is:
The x is a hexadecimal number between 0 and ff, representing 1 byte. The address bytes are always in network order.
Hostnames can contain any printable character other than a space, tab, newline, or number sign (#).
Hostnames in the /etc/ethers file should correspond to the hostnames in the /etc/hosts file or to those provided by the name service.
The following is a sample ethers file:
08:00:20:01:e5:1c host1 # Comments go here 08:00:20:01:d0:4c host2 # Comments go here 08:00:20:01:e0:1d host3 # Comments go here 08:00:20:00:c2:4e host4 # Comments go here
Files: hosts(4), packetfilter(7)
Routines: ethers(3) delim off