/usr/sbin/arp2ethers is in arpwatch 2.1a15-1.2.
This file is owned by root:root, with mode 0o755.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 | #!/bin/sh
# @(#) $Id: arp2ethers,v 1.4 2002/01/05 19:40:47 leres Exp $ (LBL)
#
# Convert arp.dat to ethers format
#
# - sort on timestamp, newest first
# - discard entries without simple hostnames
# - discard all but first occurance of each ethernet address
# - discard entires with raw ip addresses for simple names
# - remove ip address and timestamp fields
# - append "-ip" to hosts with decnet address too
# - append "-old", "-old1", etc. as necessary
# - sort
#
# 1999-04-12 KELEMEN Peter <fuji@debian.org>
# Use sh(1) instead of csh(1).
#
# 2000-03-21 Erik Warmelink <erik@selwerd.nl>
# Use next instead of continue in included p.awk.
#
# 2004-06-26 Javier Fernandez-Sanguino <jfs@debian.org>
# Use a default file or the one provided in the command line
FILE=/var/lib/arpwatch/arp.dat
[ -n "$1" ] && FILE=$1
[ -r "$FILE" ] || {
echo "Cannot read file $FILE"
exit 1
}
sort +2rn $FILE | \
awk 'NF == 4 { print }' | \
# 1999-04-12 KELEMEN Peter <fuji@debian.org>
# awk -f p.awk | \
awk '
# Only print the first ethernet address seen
{
e = $1
if (seen[e])
next
seen[e] = 1
print $0
}
' | \
egrep -v '\.[0-9][0-9]*$' | \
sed -e 's/ .* / /' | \
# 1999-04-12 KELEMEN Peter <fuji@debian.org>
# awk -f d.awk | \
awk '
# DECnet hacking
BEGIN {
n = 0
sdecnet = "aa:0:4:"
ldecnet = length(sdecnet)
}
{
++n
e[n] = $1
h[n] = $2
if (sdecnet == substr($1, 1, ldecnet))
decnet[$2] = 1
}
END {
for (i = 1; i <= n; ++i) {
if (decnet[h[i]] && sdecnet != substr(e[i], 1, ldecnet))
h[i] = h[i] "-ip"
print e[i] "\t" h[i]
}
}
' | \
# 1999-04-12 KELEMEN Peter <fuji@debian.org>
# awk -f e.awk | \
awk '
# Add -old suffix to ethers file, as required. Assumed sorted input
{
if (!seen[$2]) {
seen[$2] = 1
print
next
}
h = $2 "-old"
s = h
for (n = 1; seen[h]; ++n)
h = s n
seen[h] = 1
print $1 "\t" h
next
}
' | \
sort
|