diff --git a/script/cache_critical_dns b/script/cache_critical_dns
index ce032c4ffd5..5b75ddc97ef 100755
--- a/script/cache_critical_dns
+++ b/script/cache_critical_dns
@@ -1,6 +1,7 @@
 #!/usr/bin/env ruby
 # frozen_string_literal: true
 
+require 'ipaddr'
 require 'resolv'
 require 'time'
 require 'socket'