/etc/network/if-up.d/000resolvconf is in resolvconf 1.63ubuntu11.
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 | #!/bin/sh
#
# ifup hook script for resolvconf
#
# This file is part of the resolvconf package.
#
[ -x /sbin/resolvconf ] || exit 0
case "$ADDRFAM" in
inet|inet6) : ;;
*) exit 0 ;;
esac
R=""
if [ "$IF_DNS_DOMAIN" ] ; then
R="${R}domain $IF_DNS_DOMAIN
"
fi
if [ "$IF_DNS_SEARCH" ] ; then
R="${R}search $IF_DNS_SEARCH
"
fi
if [ "$IF_DNS_SORTLIST" ] ; then
R="${R}sortlist $IF_DNS_SORTLIST
"
fi
for NS in $IF_DNS_NAMESERVERS ; do
R="${R}nameserver $NS
"
done
echo -n "$R" | /sbin/resolvconf -a "${IFACE}.${ADDRFAM}"
|