etcnet(8) говорит: /etc/net/ifdown-post If exists and is executable, is run after ANY interface is completely gone. Однако: /etc/net#grep -r LOCALSCRIPTDIR scripts/functions scripts/ifdown-wireless scripts/functions:LOCALSCRIPTDIR=/etc/net scripts/functions:declare -rx DENOISE DEFAULT_BONDMODE IFACEDIR LOCALSCRIPTDIR VARLIBDIR scripts/ifdown-wireless:ExecIfExecutable $LOCALSCRIPTDIR/ifdown-pre-local $NAME && print_progress scripts/ifdown-wireless:ExecIfExecutable $LOCALSCRIPTDIR/ifdown-post-local $NAME && print_progress т.е. в мане нужно местами добавить "-local".
fixed in etcnet-0.9.10-alt19