#!/bin/sh

OFFSET=2012052000

if [ ! $1 ]; then
  echo "SOA: Warning - No remote host specified"
  exit 3
fi

getSerial() {
  #dig +short soa $1 @$2 | awk '{ print $3 }' | tail -n 1
  host -W 1 -t soa $1 $2 2>/dev/null | awk '/SOA/ {print $7}'
}

local=`getSerial "wleiden.net" localhost`
remote=`getSerial wleiden.net $1`

# Get errors or timeouts
if [ "$remote" = "timed" ]; then
  echo "DNS timed out"
  exit 3
fi

perf=`expr $remote - $OFFSET`
diff=`expr $local - $remote`
if [ "$local" = "$remote" ]; then
  echo "SOA: OK (Serial: $local) | soa=$perf"
  exit 0
elif [ $diff -lt 100 ]; then
  echo "SOA: WARNING - Serial difference within day ($diff) (r:$remote/$local) | soa=$perf"
  exit 1
else
  echo "SOA: ERROR - Serial difference (r:$remote/l:$local) | soa=$perf"
  exit 2
fi