Fix undefined method error

[FixRM rapid7#8343]

Author: wchen-r7

modules/auxiliary/gather/external_ip.rb

@@ -42,6 +42,12 @@ def initialize
 	def run
 		connect
 		res = send_request_cgi({'uri' => '/ip', 'method' => 'GET' })
+
+		if res.nil?
+			print_error("Connection timed out")
+			return
+		end
+
 		our_addr = res.body.strip
 		if Rex::Socket.is_ipv4?(our_addr) or Rex::Socket.is_ipv6?(our_addr)
 			print_good("Source ip to #{rhost} is #{our_addr}")