Use 127.0.0.1 for host IP when unset and 0.0.0.0 is not available

lib/vagrant/action/builtin/handle_forwarded_port_collisions.rb

@@ -243,10 +243,19 @@ module Vagrant
         end
 
         def port_check(host_ip, host_port)
-          # If the user hasn't specified a host_ip, his/her intention is taken to be
+          # If no host_ip is specified, intention taken to be list on all interfaces.
-          # to listen on all interfaces.
+          # If platform is windows, default back to localhost only
-          return is_port_open?("0.0.0.0", host_port) if host_ip.nil?
+          test_host_ip = host_ip || "0.0.0.0"
-          return is_port_open?(host_ip, host_port)
+          begin
+            is_port_open?(test_host_ip, host_port)
+          rescue Errno::EADDRNOTAVAIL
+            if !host_ip && test_host_ip == "0.0.0.0"
+              test_host_ip = "127.0.0.1"
+              retry
+            else
+              raise
+            end
+          end
         end
 
         def with_forwarded_ports(env)

test/unit/vagrant/action/builtin/handle_forwarded_port_collisions_test.rb

@@ -106,4 +106,29 @@ describe Vagrant::Action::Builtin::HandleForwardedPortCollisions do
 
   describe "#recover" do
   end
+
+  describe "#port_check" do
+    let(:host_ip){ "127.0.0.1" }
+    let(:host_port){ 8080 }
+
+    it "should check if the port is open" do
+      expect(instance).to receive(:is_port_open?).with(host_ip, host_port).and_return true
+      instance.send(:port_check, host_ip, host_port)
+    end
+
+    context "when host_ip is not set" do
+      let(:host_ip){ nil }
+
+      it "should set host_ip to 0.0.0.0 when unset" do
+        expect(instance).to receive(:is_port_open?).with("0.0.0.0", host_port).and_return true
+        instance.send(:port_check, host_ip, host_port)
+      end
+
+      it "should set host_ip to 127.0.0.1 when 0.0.0.0 is not available" do
+        expect(instance).to receive(:is_port_open?).with("0.0.0.0", host_port).and_raise Errno::EADDRNOTAVAIL
+        expect(instance).to receive(:is_port_open?).with("127.0.0.1", host_port).and_return true
+        instance.send(:port_check, host_ip, host_port)
+      end
+    end
+  end
 end