diff --git a/proxy/hdrs/HTTP.cc b/proxy/hdrs/HTTP.cc
index 9effe0a1c8a..7a56ff8934f 100644
--- a/proxy/hdrs/HTTP.cc
+++ b/proxy/hdrs/HTTP.cc
@@ -1781,6 +1781,30 @@ HTTPHdr::url_printed_length(unsigned normalization_flags)
   return zret;
 }
 
+// Look for headers that the proxy will need to be able to process
+// Return false if the proxy does not know how to process the header
+// Currently just looking at TRANSFER_ENCODING.  The proxy only knows how to
+// process the chunked action
+bool
+HTTPHdr::check_hdr_implements()
+{
+  bool retval = true;
+  MIMEField *transfer_encode =
+    mime_hdr_field_find(this->m_http->m_fields_impl, MIME_FIELD_TRANSFER_ENCODING, MIME_LEN_TRANSFER_ENCODING);
+  if (transfer_encode) {
+    int len;
+    const char *val;
+    do {
+      val = transfer_encode->value_get(&len);
+      if (len != 7 || 0 != strncasecmp(val, "chunked", len)) {
+        retval = false;
+      }
+      transfer_encode = transfer_encode->m_next_dup;
+    } while (retval && transfer_encode);
+  }
+  return retval;
+}
+
 /***********************************************************************
  *                                                                     *
  *                        M A R S H A L I N G                          *
diff --git a/proxy/hdrs/HTTP.h b/proxy/hdrs/HTTP.h
index 3196f08166d..c9dd513182d 100644
--- a/proxy/hdrs/HTTP.h
+++ b/proxy/hdrs/HTTP.h
@@ -665,6 +665,8 @@ class HTTPHdr : public MIMEHdr
                         size_t max_request_line_size = UINT16_MAX, size_t max_hdr_field_size = UINT16_MAX);
   ParseResult parse_resp(HTTPParser *parser, IOBufferReader *r, int *bytes_used, bool eof);
 
+  bool check_hdr_implements();
+
 public:
   // Utility routines
   bool is_cache_control_set(const char *cc_directive_wks);
diff --git a/proxy/http/HttpSM.cc b/proxy/http/HttpSM.cc
index 3b5deb15062..9b12eb83e8e 100644
--- a/proxy/http/HttpSM.cc
+++ b/proxy/http/HttpSM.cc
@@ -848,6 +848,12 @@ HttpSM::state_read_client_request_header(int event, void *data)
   case PARSE_RESULT_DONE:
     SMDebug("http", "[%" PRId64 "] done parsing client request header", sm_id);
 
+    if (!t_state.hdr_info.client_request.check_hdr_implements()) {
+      t_state.http_return_code = HTTP_STATUS_NOT_IMPLEMENTED;
+      call_transact_and_set_next_state(HttpTransact::BadRequest);
+      break;
+    }
+
     if (_from_early_data) {
       // Only allow early data for safe methods defined in RFC7231 Section 4.2.1.
       // https://tools.ietf.org/html/rfc7231#section-4.2.1
@@ -2051,6 +2057,13 @@ HttpSM::state_read_server_response_header(int event, void *data)
     // fallthrough
 
   case PARSE_RESULT_DONE:
+
+    if (!t_state.hdr_info.server_response.check_hdr_implements()) {
+      t_state.http_return_code = HTTP_STATUS_BAD_GATEWAY;
+      call_transact_and_set_next_state(HttpTransact::BadRequest);
+      break;
+    }
+
     SMDebug("http_seq", "Done parsing server response header");
 
     // Now that we know that we have all of the origin server
diff --git a/proxy/http/HttpTransact.cc b/proxy/http/HttpTransact.cc
index 521ac5721e0..b92e8b35892 100644
--- a/proxy/http/HttpTransact.cc
+++ b/proxy/http/HttpTransact.cc
@@ -814,6 +814,10 @@ HttpTransact::BadRequest(State *s)
     status                = s->http_return_code;
     reason                = "URI Too Long";
     break;
+  case HTTP_STATUS_NOT_IMPLEMENTED:
+    status                = s->http_return_code;
+    reason                = "Field not implemented";
+    body_factory_template = "transcoding#unsupported";
   default:
     break;
   }
diff --git a/tests/gold_tests/chunked_encoding/bad_chunked_encoding.test.py b/tests/gold_tests/chunked_encoding/bad_chunked_encoding.test.py
new file mode 100644
index 00000000000..cdfc0bf9cd2
--- /dev/null
+++ b/tests/gold_tests/chunked_encoding/bad_chunked_encoding.test.py
@@ -0,0 +1,71 @@
+'''
+'''
+#  Licensed to the Apache Software Foundation (ASF) under one
+#  or more contributor license agreements.  See the NOTICE file
+#  distributed with this work for additional information
+#  regarding copyright ownership.  The ASF licenses this file
+#  to you under the Apache License, Version 2.0 (the
+#  "License"); you may not use this file except in compliance
+#  with the License.  You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+#  Unless required by applicable law or agreed to in writing, software
+#  distributed under the License is distributed on an "AS IS" BASIS,
+#  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+#  See the License for the specific language governing permissions and
+#  limitations under the License.
+
+import os
+
+Test.Summary = '''
+Test unsupported values for chunked_encoding
+'''
+
+Test.ContinueOnFail = True
+
+# Define default ATS
+ts = Test.MakeATSProcess("ts", select_ports=True, enable_tls=False)
+server = Test.MakeOriginServer("server")
+
+testName = ""
+request_header = {"headers": "POST /case1 HTTP/1.1\r\nHost: www.example.com\r\nuuid:1\r\n\r\n",
+                  "timestamp": "1469733493.993",
+                  "body": "stuff"
+                  }
+response_header = {"headers": "HTTP/1.1 200 OK\r\nServer: uServer\r\nConnection: close\r\nTransfer-Encoding: chunked\r\n\r\n",
+                   "timestamp": "1469733493.993",
+                   "body": "more stuff"}
+
+server.addResponse("sessionlog.json", request_header, response_header)
+
+ts.Disk.records_config.update({'proxy.config.diags.debug.enabled': 0,
+                               'proxy.config.diags.debug.tags': 'http'})
+
+ts.Disk.remap_config.AddLine(
+    'map / http://127.0.0.1:{0}'.format(server.Variables.Port)
+)
+
+# HTTP1.1 POST: www.example.com/case1 with gzip transfer-encoding
+tr = Test.AddTestRun()
+tr.TimeOut = 5
+tr.Processes.Default.Command = 'curl -H "host: example.com" -H "transfer-encoding: gzip" -d "stuff" http://127.0.0.1:{0}/case1  --verbose'.format(
+    ts.Variables.port)
+tr.Processes.Default.ReturnCode = 0
+tr.Processes.Default.StartBefore(server)
+tr.Processes.Default.StartBefore(Test.Processes.ts)
+tr.Processes.Default.Streams.All = Testers.ContainsExpression("501 Field not implemented", "Should fail")
+tr.Processes.Default.Streams.All = Testers.ExcludesExpression("200 OK", "Should not succeed")
+tr.StillRunningAfter = server
+tr.StillRunningAfter = ts
+
+# HTTP1.1 POST: www.example.com/case1 with gzip and chunked transfer-encoding
+tr = Test.AddTestRun()
+tr.TimeOut = 5
+tr.Processes.Default.Command = 'curl -H "host: example.com" -H "transfer-encoding: gzip" -H "transfer-encoding: chunked" -d "stuff" http://127.0.0.1:{0}/case1  --verbose'.format(
+    ts.Variables.port)
+tr.Processes.Default.ReturnCode = 0
+tr.Processes.Default.Streams.All = Testers.ContainsExpression("501 Field not implemented", "Should fail")
+tr.Processes.Default.Streams.All = Testers.ExcludesExpression("200 OK", "Should not succeed")
+tr.StillRunningAfter = server
+tr.StillRunningAfter = ts