From f17ea36ca3d992876b58395bb9d90645b40753c2 Mon Sep 17 00:00:00 2001
From: Brendan Coles <bcoles@gmail.com>
Date: Sun, 13 Sep 2015 16:24:18 +0000
Subject: [PATCH] Rescue DNS server port unavailable - Fix #1166

---
 extensions/dns/dns.rb | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/extensions/dns/dns.rb b/extensions/dns/dns.rb
index 0f8100572..f05944b06 100644
--- a/extensions/dns/dns.rb
+++ b/extensions/dns/dns.rb
@@ -124,7 +124,18 @@ module BeEF
                   @otherwise = Proc.new { |t| t.passthrough!(resolver) }
                 end
 
-                super(:listen => listen)
+                begin
+                  super(:listen => listen)
+                rescue RuntimeError => e
+                  if e.message =~ /no datagram socket/ || e.message =~ /no acceptor/ # the port is in use
+                    print_error "[DNS] Another process is already listening on port #{options[:listen]}"
+                    print_error "Exiting..."
+                    exit 127
+                  else
+                    raise
+                  end
+                end
+
               end
             end
           end