Bash: Check if IP-Address is valid

check.sh

function valid_ip()
{
    local  ip=$1
    local  stat=1
    regexv6='^([0-9a-fA-F]{0,4}:){1,7}[0-9a-fA-F]{0,4}$'

    if [[ $ip =~ ^[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}$ ]]; then
        OIFS=$IFS
        IFS='.'
        ip=($ip)
        IFS=$OIFS
        [[ ${ip[0]} -le 255 && ${ip[1]} -le 255 \
            && ${ip[2]} -le 255 && ${ip[3]} -le 255 ]]
        stat=$?

    elif [[ $ip =~ $regexv6 ]]; then
        stat=0
    fi
    return $stat
}

cat my_ip_list.txt | while read ipadr 
do

   if valid_ip $ipadr; then 
      echo IP $ipadr is a valid IP!
   else 
      echo IP $ipadr is a not a IP, skipping!.
   fi
done