man > ethers(5)

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📄 NAME

ethers — Ethernet address to IP number database

🚀 Quick Reference

Use Case	Command	Description
🔍 Look up IP by MAC	grep 08:00:20:00:61:CA /etc/ethers	Find IP address for a given Ethernet address
🔍 Look up MAC by IP	grep 192.168.1.1 /etc/ethers	Find Ethernet address for a given IP
📝 Add a static mapping	echo "08:00:20:00:61:CA pal" >> /etc/ethers	Append a new MAC-to-IP entry (requires root)
🔧 Generate rarp table	rarp -f /etc/ethers	Populate RARP table from ethers file
✅ Validate syntax	awk '!/^#/ && NF' /etc/ethers | wc -l	Count non-comment entries (basic sanity check)

📖 DESCRIPTION

/etc/ethers contains 48-bit Ethernet addresses and their corresponding IP numbers, one line for each IP number:

Ethernet-address  IP-number

📝 The two items are separated by any number of SPACE and/or TAB characters. A # at the beginning of a line starts a comment which extends to the end of the line.

🔢 The Ethernet-address is written as x:x:x:x:x:x, where x is a hexadecimal number between 0 and ff which represents one byte of the address, in network byte order (big-endian).

🌐 The IP-number may be a hostname which can be resolved by DNS or a dot-separated number.

💡 EXAMPLES

08:00:20:00:61:CA  pal

This maps the MAC address 08:00:20:00:61:CA to the host pal.

📁 FILES

• 📄 /etc/ethers — Ethernet address to IP mapping database

🔗 SEE ALSO

• rarp(8) — manipulate RARP table

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net-tools — 2008-10-03 — ETHERS(5)

📄 NAME 🚀 Quick Reference 📖 DESCRIPTION 💡 EXAMPLES 📁 FILES 🔗 SEE ALSO