diff --git a/Network/DomainAuth/DK/Parser.hs b/Network/DomainAuth/DK/Parser.hs
--- a/Network/DomainAuth/DK/Parser.hs
+++ b/Network/DomainAuth/DK/Parser.hs
@@ -9,7 +9,6 @@
 import Data.Maybe
 import Network.DomainAuth.DK.Types
 import Network.DomainAuth.Mail
-import Prelude hiding (catch)
 
 {-|
   Parsing DomainKey-Signature:.
diff --git a/Network/DomainAuth/DK/Verify.hs b/Network/DomainAuth/DK/Verify.hs
--- a/Network/DomainAuth/DK/Verify.hs
+++ b/Network/DomainAuth/DK/Verify.hs
@@ -53,7 +53,7 @@
 ----------------------------------------------------------------
 
 verifyDK :: Mail -> DK -> PublicKey -> Bool
-verifyDK mail dk pub = rsassa_pkcs1_v1_5_verify ha_SHA1 pub cmail sig
+verifyDK mail dk pub = rsassa_pkcs1_v1_5_verify hashSHA1 pub cmail sig
   where
     sig = B.decode . dkSignature $ dk
     cmail = toLazyByteString (prepareDK dk mail)
diff --git a/Network/DomainAuth/DKIM/Btag.hs b/Network/DomainAuth/DKIM/Btag.hs
--- a/Network/DomainAuth/DKIM/Btag.hs
+++ b/Network/DomainAuth/DKIM/Btag.hs
@@ -1,5 +1,6 @@
 module Network.DomainAuth.DKIM.Btag where
 
+import Control.Monad
 import Data.ByteString.Char8
 import Data.Maybe
 import Text.Appar.ByteString
@@ -18,6 +19,6 @@
     b <- string "b"
     w <- many $ oneOf " \t\r\n"
     e <- string "="
-    some $ noneOf ";"
+    void . some $ noneOf ";"
     s <- option "" (string ";")
     return $ b ++ w ++ e ++ s
diff --git a/Network/DomainAuth/DKIM/Parser.hs b/Network/DomainAuth/DKIM/Parser.hs
--- a/Network/DomainAuth/DKIM/Parser.hs
+++ b/Network/DomainAuth/DKIM/Parser.hs
@@ -8,7 +8,6 @@
 import Data.Maybe
 import Network.DomainAuth.DKIM.Types
 import Network.DomainAuth.Mail
-import Prelude hiding (catch)
 
 {-|
   Parsing DKIM-Signature:.
diff --git a/Network/DomainAuth/DKIM/Verify.hs b/Network/DomainAuth/DKIM/Verify.hs
--- a/Network/DomainAuth/DKIM/Verify.hs
+++ b/Network/DomainAuth/DKIM/Verify.hs
@@ -57,8 +57,8 @@
     bodyHash2 = B.decode . dkimBodyHash
 
 hashAlgo1 :: DkimSigAlgo -> HashInfo
-hashAlgo1 RSA_SHA1   = ha_SHA1
-hashAlgo1 RSA_SHA256 = ha_SHA256
+hashAlgo1 RSA_SHA1   = hashSHA1
+hashAlgo1 RSA_SHA256 = hashSHA256
 
 hashAlgo2 :: DkimSigAlgo -> BL.ByteString -> BL.ByteString
 hashAlgo2 RSA_SHA1   = bytestringDigest . sha1
diff --git a/Network/DomainAuth/Pubkey/RSAPub.hs b/Network/DomainAuth/Pubkey/RSAPub.hs
--- a/Network/DomainAuth/Pubkey/RSAPub.hs
+++ b/Network/DomainAuth/Pubkey/RSAPub.hs
@@ -4,6 +4,7 @@
 
 import Codec.Crypto.RSA
 import Control.Applicative
+import Crypto.Types.PubKey.RSA
 import Data.ByteString (ByteString)
 import qualified Data.ByteString as BS (foldl', dropWhile, length, tail)
 import qualified Data.ByteString.Char8 as BS ()
@@ -20,10 +21,14 @@
     decode = (>>= return . decodeRSAPublicyKey)
 
 lookupPublicKey' :: DNS.Resolver -> Domain -> IO (Maybe ByteString)
-lookupPublicKey' resolver domain = extractPub <$> DNS.lookupTXT resolver domain
+lookupPublicKey' resolver domain = do
+    ex <- DNS.lookupTXT resolver domain
+    case ex of
+        Left  _ -> return Nothing
+        Right x -> return $ extractPub x
 
-extractPub :: Maybe [ByteString] -> Maybe ByteString
-extractPub = (>>= lookup "p" . parseTaggedValue . head)
+extractPub :: [ByteString] -> Maybe ByteString
+extractPub = lookup "p" . parseTaggedValue . head
 
 decodeRSAPublicyKey :: ByteString -> PublicKey
 decodeRSAPublicyKey bs = PublicKey size n e
diff --git a/Network/DomainAuth/SPF.hs b/Network/DomainAuth/SPF.hs
--- a/Network/DomainAuth/SPF.hs
+++ b/Network/DomainAuth/SPF.hs
@@ -8,11 +8,12 @@
   , defaultLimit
   ) where
 
+import Control.Exception as E
 import Data.IP
 import Network.DNS (Domain, Resolver)
-import Network.DomainAuth.Types
 import Network.DomainAuth.SPF.Eval
 import Network.DomainAuth.SPF.Resolver
+import Network.DomainAuth.Types
 import System.IO.Error
 
 {-|
@@ -24,7 +25,7 @@
 -}
 runSPF :: Limit -> Resolver -> Domain -> IP -> IO DAResult
 runSPF lim resolver dom ip =
-    (resolveSPF resolver dom ip >>= evalSPF lim ip) `catch` spfErrorHandle
+    (resolveSPF resolver dom ip >>= evalSPF lim ip) `E.catch` spfErrorHandle
 
 spfErrorHandle :: IOError -> IO DAResult
 spfErrorHandle e = case ioeGetErrorString e of
diff --git a/Network/DomainAuth/SPF/Resolver.hs b/Network/DomainAuth/SPF/Resolver.hs
--- a/Network/DomainAuth/SPF/Resolver.hs
+++ b/Network/DomainAuth/SPF/Resolver.hs
@@ -24,8 +24,12 @@
     let is = filterSPFWithIP ip (fromJust jrs)
     return $ map (toSpfSeq resolver dom ip) is
   where
-    getSPFRR jrc = let ts = filter ("v=spf1" `BS.isPrefixOf`) (fromJust jrc)
-                   in if null ts then "" else head ts
+    getSPFRR (Left _) = error "getSPRRR"
+    getSPFRR (Right rc)
+      | null ts   = ""
+      | otherwise = head ts
+      where
+        ts = filter ("v=spf1" `BS.isPrefixOf`) rc
     checkSyntax rs estr = when (isNothing rs) (fail estr)
     checkExistence rr estr = when (BS.null rr) (fail estr)
 
@@ -69,21 +73,20 @@
 toSpfSeq r _   (IPv6 _) (SPF_Address q (Just dom) (_,l6))
     = lookupAAAA r dom >>= doit6 q l6
 
-doit4 :: Qualifier -> Int -> Maybe [IPv4] -> IO SpfSeq
-doit4 q l4 is = do
-    checkDNS is "TempError"
-    return $ SS_IPv4Ranges q $ map (mkr l4) $ fromJust is
+doit4 :: Qualifier -> Int -> Either DNSError [IPv4] -> IO SpfSeq
+doit4 _ _  (Left _)   = fail "TempError"
+doit4 q l4 (Right is) = return $ SS_IPv4Ranges q $ map (mkr l4) is
   where
     mkr = flip makeAddrRange
 
-doit6 :: Qualifier -> Int -> Maybe [IPv6] -> IO SpfSeq
-doit6 q l6 is = do
-    checkDNS is "TempError"
-    return $ SS_IPv6Ranges q $ map (mkr l6) $ fromJust is
+doit6 :: Qualifier -> Int -> Either DNSError [IPv6] -> IO SpfSeq
+doit6 _ _  (Left _)   = fail "TempError"
+doit6 q l6 (Right is) = return $ SS_IPv6Ranges q $ map (mkr l6) is
   where
     mkr = flip makeAddrRange
 
 ----------------------------------------------------------------
 
-checkDNS :: Maybe a -> String -> IO ()
-checkDNS jrc estr = when (isNothing jrc) (fail estr)
+checkDNS :: Either DNSError a -> String -> IO ()
+checkDNS (Right _) _    = return ()
+checkDNS (Left  _) estr = fail estr
diff --git a/domain-auth.cabal b/domain-auth.cabal
--- a/domain-auth.cabal
+++ b/domain-auth.cabal
@@ -1,5 +1,5 @@
 Name:                   domain-auth
-Version:                0.2.0
+Version:                0.2.1
 Author:                 Kazu Yamamoto <kazu@iij.ad.jp>
 Maintainer:             Kazu Yamamoto <kazu@iij.ad.jp>
 License:                BSD3
@@ -11,10 +11,7 @@
 Cabal-Version:          >= 1.6
 Build-Type:             Simple
 library
-  if impl(ghc >= 6.12)
-    GHC-Options:        -Wall -fno-warn-unused-do-bind
-  else
-    GHC-Options:        -Wall
+  GHC-Options:          -Wall
   Exposed-Modules:      Network.DomainAuth
                         Network.DomainAuth.Mail
                         Network.DomainAuth.DK
@@ -44,9 +41,18 @@
                         Network.DomainAuth.SPF.Parser
                         Network.DomainAuth.SPF.Resolver
                         Network.DomainAuth.SPF.Types
-  Build-Depends:        base >= 4 && < 5, appar, dns, iproute,
-                        network, bytestring, RSA, binary,
-                        containers, SHA, blaze-builder
+  Build-Depends:        base >= 4 && < 5
+                      , RSA >= 2.0
+                      , SHA
+                      , appar
+                      , binary
+                      , blaze-builder
+                      , bytestring
+                      , containers
+                      , crypto-pubkey-types
+                      , dns >= 1.0
+                      , iproute
+                      , network
 Source-Repository head
   Type:                 git
   Location:             git://github.com/kazu-yamamoto/domain-auth.git