diff --git a/src/usr/bin/google_set_hostname b/src/usr/bin/google_set_hostname
index 5a2ac50..317768f 100755
--- a/src/usr/bin/google_set_hostname
+++ b/src/usr/bin/google_set_hostname
@@ -40,14 +40,15 @@ fi
 #     a FQDN that is > 64 bytes.
 #
 # As a result, we set the host name whenever a new host name is set - ignoring when
-# old_fqdn is equal to new_host_name, to the truncated unqualified domain name.
+# old_hostname is equal to new_host_name's host part, to the truncated unqualified
+# domain name.
 
 hostnamecli=$(which hostname 2> /dev/null)
 if [ -x "$hostnamecli" ]; then
-  old_fqdn=$($hostnamecli -f)
+  old_hostname=$($hostnamecli)
 fi
 
-if [ -n "$new_host_name" ] && [ "$new_host_name" != "$old_fqdn" ] && ! echo "$new_host_name" | grep -iq "metadata.google.internal"; then
+if [ -n "$new_host_name" ] && [ "${new_host_name%%.*}" != "$old_hostname" ] && ! echo "$new_host_name" | grep -iq "metadata.google.internal"; then
   hostname "${new_host_name%%.*}"
 
   # If NetworkManager is installed set the hostname with nmcli.