diff --git a/ens/constants.py b/ens/constants.py
index 78455f4e30..464a303fad 100644
--- a/ens/constants.py
+++ b/ens/constants.py
@@ -17,4 +17,4 @@
 
 REVERSE_REGISTRAR_DOMAIN = 'addr.reverse'
 
-ENS_MAINNET_ADDR = ChecksumAddress(HexAddress(HexStr('0x00000000000C2E074eC69A0dFb2997BA6C7d2e1e')))
+ENS_PUBLIC_ADDR = ChecksumAddress(HexAddress(HexStr('0x00000000000C2E074eC69A0dFb2997BA6C7d2e1e')))
diff --git a/ens/main.py b/ens/main.py
index 1a8152e833..567d6a3137 100644
--- a/ens/main.py
+++ b/ens/main.py
@@ -24,7 +24,7 @@
 from ens import abis
 from ens.constants import (
     EMPTY_ADDR_HEX,
-    ENS_MAINNET_ADDR,
+    ENS_PUBLIC_ADDR,
     REVERSE_REGISTRAR_DOMAIN,
 )
 from ens.exceptions import (
@@ -83,10 +83,11 @@ def __init__(
         :type provider: instance of `web3.providers.base.BaseProvider`
         :param hex-string addr: the address of the ENS registry on-chain. If not provided,
             ENS.py will default to the mainnet ENS registry address.
+        :raises UnknownNetwork: if network is unknown
         """
         self.web3 = init_web3(provider)
 
-        ens_addr = addr if addr else ENS_MAINNET_ADDR
+        ens_addr = addr if addr else ENS_PUBLIC_ADDR
         self.ens = self.web3.eth.contract(abi=abis.ENS, address=ens_addr)
         self._resolverContract = self.web3.eth.contract(abi=abis.RESOLVER)
 
diff --git a/ens/utils.py b/ens/utils.py
index 08eb211b94..8f92aabf18 100644
--- a/ens/utils.py
+++ b/ens/utils.py
@@ -87,12 +87,20 @@ def init_web3(provider: 'BaseProvider'=cast('BaseProvider', default)) -> '_Web3'
 
 def customize_web3(w3: '_Web3') -> '_Web3':
     from web3.middleware import make_stalecheck_middleware
+    from web3.middleware import geth_poa_middleware
 
     w3.middleware_onion.remove('name_to_address')
+
     w3.middleware_onion.add(
         make_stalecheck_middleware(ACCEPTABLE_STALE_HOURS * 3600),
         name='stalecheck',
     )
+
+    w3.middleware_onion.inject(
+        geth_poa_middleware,
+        layer=0,
+    )
+
     return w3
 
 
diff --git a/web3/middleware/stalecheck.py b/web3/middleware/stalecheck.py
index b9117e2f70..38262500f6 100644
--- a/web3/middleware/stalecheck.py
+++ b/web3/middleware/stalecheck.py
@@ -22,6 +22,7 @@
 
 SKIP_STALECHECK_FOR_METHODS = set([
     'eth_getBlockByNumber',
+    'net_version',
 ])