diff --git a/vpnsetup_centos.sh b/vpnsetup_centos.sh
index f70bc0b..9591aab 100755
--- a/vpnsetup_centos.sh
+++ b/vpnsetup_centos.sh
@@ -536,8 +536,8 @@ update_iptables() {
 }
 
 apply_gcp_mtu_fix() {
-  if dmidecode -s system-product-name 2>/dev/null | grep -q "Google Compute Engine" \
-    && ifconfig 2>/dev/null | grep "$NET_IFACE" | head -n 1 | grep -q "mtu 1460"; then
+  if dmidecode -s system-product-name 2>/dev/null | grep -qi 'Google Compute Engine' \
+    && ifconfig 2>/dev/null | grep "$NET_IFACE" | head -n 1 | grep -qi 'mtu 1460'; then
     bigecho "Applying fix for MTU size..."
     ifconfig "$NET_IFACE" mtu 1500
     dh_file="/etc/dhcp/dhclient.conf"
diff --git a/vpnsetup_ubuntu.sh b/vpnsetup_ubuntu.sh
index 6156874..49a7411 100755
--- a/vpnsetup_ubuntu.sh
+++ b/vpnsetup_ubuntu.sh
@@ -492,8 +492,8 @@ update_iptables() {
 }
 
 apply_gcp_mtu_fix() {
-  if dmidecode -s system-product-name 2>/dev/null | grep -q "Google Compute Engine" \
-    && ifconfig 2>/dev/null | grep "$NET_IFACE" | head -n 1 | grep -q "mtu 1460"; then
+  if dmidecode -s system-product-name 2>/dev/null | grep -qi 'Google Compute Engine' \
+    && ifconfig 2>/dev/null | grep "$NET_IFACE" | head -n 1 | grep -qi 'mtu 1460'; then
     bigecho "Applying fix for MTU size..."
     ifconfig "$NET_IFACE" mtu 1500
     dh_file="/etc/dhcp/dhclient.conf"