diff --git a/ChangeLog.md b/ChangeLog.md
--- a/ChangeLog.md
+++ b/ChangeLog.md
@@ -1,5 +1,9 @@
 # Revision history for ip2proxy
 
+## 2.1.0 -- 2019-07-22
+
+* Added support for 6to4 and Teredo.
+
 ## 2.0.0 -- 2019-05-27
 
 * Added support for PX5 to PX8 packages.
diff --git a/IP2Proxy.hs b/IP2Proxy.hs
--- a/IP2Proxy.hs
+++ b/IP2Proxy.hs
@@ -99,7 +99,7 @@
     The 'getModuleVersion' function returns a string containing the module version.
 -}
 getModuleVersion :: String
-getModuleVersion = "2.0.0"
+getModuleVersion = "2.1.0"
 
 {-|
     The 'getPackageVersion' function returns a string containing the package version.
@@ -435,21 +435,32 @@
 doQuery :: String -> Meta -> String -> Int -> IO IP2ProxyRecord
 doQuery myfile meta myip mode = do
     contents <- BS.readFile myfile
-    let from = 281470681743360
-    let to = 281474976710655
-    let fromA = 0
-    let toA = 4294967295
+    let fromV4Mapped = 281470681743360
+    let toV4Mapped = 281474976710655
+    let fromV4Compatible = 0
+    let toV4Compatible = 4294967295
+    let from6To4 = 42545680458834377588178886921629466624
+    let to6To4 = 42550872755692912415807417417958686719
+    let fromTeredo = 42540488161975842760550356425300246528
+    let toTeredo = 42540488241204005274814694018844196863
+    let last32Bits = 4294967295
     
     ipnum <- tryfirst myip
     if ipnum == -1
         then do
             let x = "INVALID IP ADDRESS"
             return $ IP2ProxyRecord x x x x x x x x x x x (-1)
-        else if ipnum >= from && ipnum <= to
+        else if ipnum >= fromV4Mapped && ipnum <= toV4Mapped
             then do
-                return $ search4 contents (ipnum - (toInteger from)) (databasetype meta) 0 (ipv4databasecount meta) (ipv4databaseaddr meta) (ipv4indexbaseaddr meta) (ipv4columnsize meta) mode
-            else if ipnum >= fromA && ipnum <= toA
+                return $ search4 contents (ipnum - (toInteger fromV4Mapped)) (databasetype meta) 0 (ipv4databasecount meta) (ipv4databaseaddr meta) (ipv4indexbaseaddr meta) (ipv4columnsize meta) mode
+            else if ipnum >= from6To4 && ipnum <= to6To4
                 then do
-                    return $ search4 contents ipnum (databasetype meta) 0 (ipv4databasecount meta) (ipv4databaseaddr meta) (ipv4indexbaseaddr meta) (ipv4columnsize meta) mode
-                else do
-                    return $ search6 contents ipnum (databasetype meta) 0 (ipv6databasecount meta) (ipv6databaseaddr meta) (ipv6indexbaseaddr meta) (ipv6columnsize meta) mode
+                    return $ search4 contents ((ipnum `rotateR` 80) .&. last32Bits) (databasetype meta) 0 (ipv4databasecount meta) (ipv4databaseaddr meta) (ipv4indexbaseaddr meta) (ipv4columnsize meta) mode
+                else if ipnum >= fromTeredo && ipnum <= toTeredo
+                    then do
+                        return $ search4 contents ((complement ipnum) .&. last32Bits) (databasetype meta) 0 (ipv4databasecount meta) (ipv4databaseaddr meta) (ipv4indexbaseaddr meta) (ipv4columnsize meta) mode
+                    else if ipnum >= fromV4Compatible && ipnum <= toV4Compatible
+                        then do
+                            return $ search4 contents ipnum (databasetype meta) 0 (ipv4databasecount meta) (ipv4databaseaddr meta) (ipv4indexbaseaddr meta) (ipv4columnsize meta) mode
+                        else do
+                            return $ search6 contents ipnum (databasetype meta) 0 (ipv6databasecount meta) (ipv6databaseaddr meta) (ipv6indexbaseaddr meta) (ipv6columnsize meta) mode
diff --git a/LICENSE b/LICENSE
--- a/LICENSE
+++ b/LICENSE
@@ -1,21 +1,21 @@
-MIT License
-
-Copyright (c) 2019 IP2Location.com
-
-Permission is hereby granted, free of charge, to any person obtaining a copy
-of this software and associated documentation files (the "Software"), to deal
-in the Software without restriction, including without limitation the rights
-to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
-copies of the Software, and to permit persons to whom the Software is
-furnished to do so, subject to the following conditions:
-
-The above copyright notice and this permission notice shall be included in all
-copies or substantial portions of the Software.
-
-THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
-SOFTWARE.
+MIT License
+
+Copyright (c) 2019 IP2Location.com
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
diff --git a/ip2proxy.cabal b/ip2proxy.cabal
--- a/ip2proxy.cabal
+++ b/ip2proxy.cabal
@@ -10,7 +10,7 @@
 -- PVP summary:      +-+------- breaking API changes
 --                   | | +----- non-breaking API additions
 --                   | | | +--- code changes with no API change
-version:             2.0.0
+version:             2.1.0
 
 -- A short (one-line) description of the package.
 synopsis:            IP2Proxy Haskell package for proxy detection.