diff --git a/network.sh b/network.sh
index 96dec21..392b4fd 100644
--- a/network.sh
+++ b/network.sh
@@ -75,7 +75,7 @@ searchdomains=$(grep '^search' /etc/resolv.conf | sed 's/search //' | sed 's/ /,
 domainname=$(echo $searchdomains | awk -F"," '{print $1}')
 
 for nameserver in "${nameservers[@]}"; do
-  if [ ! $nameserver =~ .*:.* ]; then
+  if ! [[ $nameserver =~ .*:.* ]]; then
     [[ -z $DNS_SERVERS ]] && DNS_SERVERS=$nameserver || DNS_SERVERS="$DNS_SERVERS,$nameserver"
   fi
 done