diff --git a/actions/dynamicdns b/actions/dynamicdns
index 4b45a8c37..3968d744f 100755
--- a/actions/dynamicdns
+++ b/actions/dynamicdns
@@ -374,10 +374,10 @@ case ${cmd} in
         fi
         # if we don't know our WAN IP do a blind update once a hour
         if [ "${wanip}" = ${NOIP} ];then
-            uptime=$(cut -d . -f 1 /proc/uptime)
+            currenttime=$(date +%s)
             LAST=0
             [ -f ${LASTUPDATE} ] && LAST=$(cat ${LASTUPDATE})
-            diff=$((uptime - LAST))
+            diff=$((currenttime - LAST))
             if [ ${diff} -gt ${UPDATEMINUTESUNKNOWN} ];then
                 doUpdate
             fi
@@ -392,7 +392,7 @@ case ${cmd} in
     success)
         date=$(date)
         echo "last update done (${date})" > ${STATUSFILE}
-        awk '{print $1}' /proc/uptime |cut -d . -f 1 > ${LASTUPDATE}
+        date +%s > ${LASTUPDATE}
         # if called from cronjob, the current IP is given as parameter
         if [ $# -eq 1 ];then
             echo "${1}" > ${IPFILE}