diff --git a/lib/vagrant/util/network_ip.rb b/lib/vagrant/util/network_ip.rb
index 5f22f69d4..1a4653656 100644
--- a/lib/vagrant/util/network_ip.rb
+++ b/lib/vagrant/util/network_ip.rb
@@ -5,34 +5,9 @@ module Vagrant
     module NetworkIP
       # Returns the network address of the given IP and subnet.
       #
-      # If the IP address is an IPv6 address, subnet should be a prefix
-      # length such as "64".
-      #
       # @return [String]
       def network_address(ip, subnet)
-        # If this is an IPv6 address, then just mask it
-        if subnet.to_s =~ /^\d+$/
-          ip = IPAddr.new(ip)
-          return ip.mask(subnet.to_i).to_s
-        end
-
-        ip      = ip_parts(ip)
-        netmask = ip_parts(subnet)
-
-        # Bitwise-AND each octet to get the network address
-        # in octets and join each part with a period to get
-        # the resulting network address.
-        ip.map { |part| part & netmask.shift }.join(".")
-      end
-
-      protected
-
-      # Splits an IP into the four octets and returns each as an
-      # integer in an array.
-      #
-      # @return [Array<Integer>]
-      def ip_parts(ip)
-        ip.split(".").map { |i| i.to_i }
+        IPAddr.new(ip).mask(subnet).to_s
       end
     end
   end
diff --git a/test/unit/vagrant/util/network_ip_test.rb b/test/unit/vagrant/util/network_ip_test.rb
index 9d0d09b12..5351f4f9a 100644
--- a/test/unit/vagrant/util/network_ip_test.rb
+++ b/test/unit/vagrant/util/network_ip_test.rb
@@ -18,6 +18,10 @@ describe Vagrant::Util::NetworkIP do
       expect(klass.network_address("192.168.2.234", "24")).to eq("192.168.2.0")
     end
 
+    it "calculates it properly with integer submask" do
+      expect(klass.network_address("192.168.2.234", 24)).to eq("192.168.2.0")
+    end
+
     it "calculates it properly for IPv6" do
       expect(klass.network_address("fde4:8dba:82e1::c4", "64")).to eq("fde4:8dba:82e1::")
     end
@@ -25,5 +29,9 @@ describe Vagrant::Util::NetworkIP do
     it "calculates it properly for IPv6" do
       expect(klass.network_address("fde4:8dba:82e1::c4", 64)).to eq("fde4:8dba:82e1::")
     end
+
+    it "calculates it properly for IPv6 for string mask" do
+      expect(klass.network_address("fde4:8dba:82e1::c4", "ffff:ffff:ffff:ffff::")).to eq("fde4:8dba:82e1::")
+    end
   end
 end