diff --git a/dynhost.sh b/dynhost.sh
index 5414f02..f199d71 100644
--- a/dynhost.sh
+++ b/dynhost.sh
@@ -1,26 +1,46 @@
 #!/usr/bin/env sh
-
+# Function to verify If IP adress is valid
+check_ip () {
+  rxV4='([1-9]?[0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])'
+  rxV6='(([0-9a-fA-F]{1,4}:){7,7}[0-9a-fA-F]{1,4}|([0-9a-fA-F]{1,4}:){1,7}:|([0-9a-fA-F]{1,4}:){1,6}:[0-9a-fA-F]{1,4}|([0-9a-fA-F]{1,4}:){1,5}(:[0-9a-fA-F]{1,4}){1,2}|([0-9a-fA-F]{1,4}:){1,4}(:[0-9a-fA-F]{1,4}){1,3}|([0-9a-fA-F]{1,4}:){1,3}(:[0-9a-fA-F]{1,4}){1,4}|([0-9a-fA-F]{1,4}:){1,2}(:[0-9a-fA-F]{1,4}){1,5}|[0-9a-fA-F]{1,4}:((:[0-9a-fA-F]{1,4}){1,6})|:((:[0-9a-fA-F]{1,4}){1,7}|:)|fe80:(:[0-9a-fA-F]{0,4}){0,4}%[0-9a-zA-Z]{1,}|::(ffff(:0{1,4}){0,1}:){0,1}((25[0-5]|(2[0-4]|1{0,1}[0-9]){0,1}[0-9])\.){3,3}(25[0-5]|(2[0-4]|1{0,1}[0-9]){0,1}[0-9])|([0-9a-fA-F]{1,4}:){1,4}:((25[0-5]|(2[0-4]|1{0,1}[0-9]){0,1}[0-9])\.){3,3}(25[0-5]|(2[0-4]|1{0,1}[0-9]){0,1}[0-9]))'
+  
+  if [ "$2" == "V4" ]
+  then
+    if ! [[ $1 =~ ^$rxV4\.$rxV4\.$rxV4\.$rxV4$ ]]; then
+      exit 5
+    fi
+  elif [ "$2" == "V6"  ]
+  then
+    if ! [[ $1 =~ ^$rxV6$ ]]; then
+      exit 5
+    fi
+  else
+    exit 6
+  fi
+}
 # Account configuration
+IP_VERSION="V4"
 HOST=DOMAINE_NAME
 LOGIN=LOGIN
 PASSWORD=PASSWORD
 
 PATH_LOG=/var/log/dynhostovh.log
-
 # Get current IPv4 and corresponding configured
 HOST_IP=$(dig +short $HOST A)
-CURRENT_IP=$(curl -m 5 -4 ifconfig.co 2>/dev/null)
-if [ -z $CURRENT_IP ]
-then
-  CURRENT_IP=$(dig +short myip.opendns.com @resolver1.opendns.com)
+
+
+CURRENT_IP=$(dig +short myip.opendns.com @resolver1.opendns.com)
+if [ -z "$CURRENT_IP" ]; then
+  CURRENT_IP=`curl -m 5 -4 ifconfig.co 2>/dev/null`
 fi
 CURRENT_DATETIME=$(date -R)
 
-# Update dynamic IPv4, if needed
-if [ -z $CURRENT_IP ] || [ -z $HOST_IP ]
+# # Update dynamic IPv4, if needed
+if [ -z "$CURRENT_IP" ] || [ -z "$HOST_IP" ]
 then
-  echo "[$CURRENT_DATETIME]: No IP retrieved" >> $PATH_LOG
+  echo "[$CURRENT_DATETIME]: No IP retrieved"
 else
+  check_ip $CURRENT_IP $IP_VERSION
   if [ "$HOST_IP" != "$CURRENT_IP" ]
   then
     RES=$(curl -m 5 -L --location-trusted --user "$LOGIN:$PASSWORD" "https://www.ovh.com/nic/update?system=dyndns&hostname=$HOST&myip=$CURRENT_IP")