diff --git a/netlib/http/models.py b/netlib/http/models.py
index 3c360a371..512a764d4 100644
--- a/netlib/http/models.py
+++ b/netlib/http/models.py
@@ -216,7 +216,7 @@ class Message(object):
     def body(self, body):
         self._body = body
         if isinstance(body, bytes):
-            self.headers[b"Content-Length"] = str(len(body)).encode()
+            self.headers[b"content-length"] = str(len(body)).encode()
 
     content = body
 
@@ -268,8 +268,8 @@ class Request(Message):
             response. That is, we remove ETags and If-Modified-Since headers.
         """
         delheaders = [
-            b"If-Modified-Since",
-            b"If-None-Match",
+            b"if-modified-since",
+            b"if-none-match",
         ]
         for i in delheaders:
             self.headers.pop(i, None)
@@ -279,16 +279,16 @@ class Request(Message):
             Modifies this request to remove headers that will compress the
             resource's data.
         """
-        self.headers["Accept-Encoding"] = "identity"
+        self.headers["accept-encoding"] = b"identity"
 
     def constrain_encoding(self):
         """
             Limits the permissible Accept-Encoding values, based on what we can
             decode appropriately.
         """
-        accept_encoding = native(self.headers.get("Accept-Encoding"), "ascii")
+        accept_encoding = native(self.headers.get("accept-encoding"), "ascii")
         if accept_encoding:
-            self.headers["Accept-Encoding"] = (
+            self.headers["accept-encoding"] = (
                 ', '.join(
                     e
                     for e in encoding.ENCODINGS
@@ -300,7 +300,7 @@ class Request(Message):
         """
             Update the host header to reflect the current target.
         """
-        self.headers["Host"] = self.host
+        self.headers["host"] = self.host
 
     def get_form(self):
         """
@@ -309,9 +309,9 @@ class Request(Message):
             indicates non-form data.
         """
         if self.body:
-            if HDR_FORM_URLENCODED in self.headers.get("Content-Type", b"").lower():
+            if HDR_FORM_URLENCODED in self.headers.get("content-type", b"").lower():
                 return self.get_form_urlencoded()
-            elif HDR_FORM_MULTIPART in self.headers.get("Content-Type", b"").lower():
+            elif HDR_FORM_MULTIPART in self.headers.get("content-type", b"").lower():
                 return self.get_form_multipart()
         return ODict([])
 
@@ -321,12 +321,12 @@ class Request(Message):
             Returns an empty ODict if there is no data or the content-type
             indicates non-form data.
         """
-        if self.body and HDR_FORM_URLENCODED in self.headers.get("Content-Type", b"").lower():
+        if self.body and HDR_FORM_URLENCODED in self.headers.get("content-type", b"").lower():
             return ODict(utils.urldecode(self.body))
         return ODict([])
 
     def get_form_multipart(self):
-        if self.body and HDR_FORM_MULTIPART in self.headers.get("Content-Type", b"").lower():
+        if self.body and HDR_FORM_MULTIPART in self.headers.get("content-type", b"").lower():
             return ODict(
                 utils.multipartdecode(
                     self.headers,
@@ -341,7 +341,7 @@ class Request(Message):
         """
         # FIXME: If there's an existing content-type header indicating a
         # url-encoded form, leave it alone.
-        self.headers[b"Content-Type"] = HDR_FORM_URLENCODED
+        self.headers[b"content-type"] = HDR_FORM_URLENCODED
         self.body = utils.urlencode(odict.lst)
 
     def get_path_components(self):
@@ -398,9 +398,9 @@ class Request(Message):
             but not the resolved name. This is disabled by default, as an
             attacker may spoof the host header to confuse an analyst.
         """
-        if hostheader and "Host" in self.headers:
+        if hostheader and "host" in self.headers:
             try:
-                return self.headers["Host"].decode("idna")
+                return self.headers["host"].decode("idna")
             except ValueError:
                 pass
         if self.host:
@@ -429,7 +429,7 @@ class Request(Message):
             headers.
         """
         v = cookies.format_cookie_header(odict)
-        self.headers["Cookie"] = v
+        self.headers["cookie"] = v
 
     @property
     def url(self):
@@ -485,7 +485,7 @@ class Response(Message):
         return "<Response: {status_code} {msg} ({contenttype}, {size})>".format(
             status_code=self.status_code,
             msg=self.msg,
-            contenttype=self.headers.get("Content-Type", "unknown content type"),
+            contenttype=self.headers.get("content-type", "unknown content type"),
             size=size)
 
     def get_cookies(self):
@@ -498,7 +498,7 @@ class Response(Message):
             attributes (e.g. HTTPOnly) are indicated by a Null value.
         """
         ret = []
-        for header in self.headers.get_all("Set-Cookie"):
+        for header in self.headers.get_all("set-cookie"):
             v = cookies.parse_set_cookie_header(native(header, "ascii"))
             if v:
                 name, value, attrs = v
@@ -521,4 +521,4 @@ class Response(Message):
                     i[1][1]
                 )
             )
-        self.headers.set_all("Set-Cookie", values)
+        self.headers.set_all("set-cookie", values)
diff --git a/netlib/tcp.py b/netlib/tcp.py
index 40ffbd486..b751d71f4 100644
--- a/netlib/tcp.py
+++ b/netlib/tcp.py
@@ -279,6 +279,7 @@ class Reader(_FileLike):
                 if tuple(int(x) for x in OpenSSL.__version__.split(".")[:2]) > (0, 15):
                     return self.o.recv(length, socket.MSG_PEEK)
                 else:
+                    # TODO: remove once a new version is released
                     # Polyfill for pyOpenSSL <= 0.15.1
                     # Taken from https://github.com/pyca/pyopenssl/commit/1d95dea7fea03c7c0df345a5ea30c12d8a0378d2
                     buf = SSL._ffi.new("char[]", length)