diff --git a/src/HttpHeader.cc b/src/HttpHeader.cc
index dc6e0ff..67543a4 100644
--- a/src/HttpHeader.cc
+++ b/src/HttpHeader.cc
@@ -174,6 +174,7 @@ HttpHeader::operator =(const HttpHeader &other)
         update(&other); // will update the mask as well
         len = other.len;
         conflictingContentLength_ = other.conflictingContentLength_;
+        teUnsupported_ = other.teUnsupported_;
     }
     return *this;
 }
@@ -222,6 +223,7 @@ HttpHeader::clean()
     httpHeaderMaskInit(&mask, 0);
     len = 0;
     conflictingContentLength_ = false;
+    teUnsupported_ = false;
     PROF_stop(HttpHeaderClean);
 }
 
@@ -464,11 +466,23 @@ HttpHeader::parse(const char *header_start, size_t hdrLen)
                Raw("header", header_start, hdrLen));
     }
 
-    if (chunked()) {
+    String rawTe;
+    if (getByIdIfPresent(Http::HdrType::TRANSFER_ENCODING, &rawTe)) {
         // RFC 2616 section 4.4: ignore Content-Length with Transfer-Encoding
         // RFC 7230 section 3.3.3 #3: Transfer-Encoding overwrites Content-Length
         delById(Http::HdrType::CONTENT_LENGTH);
         // and clen state becomes irrelevant
+
+        if (rawTe == "chunked") {
+            ; // leave header present for chunked() method
+        } else if (rawTe == "identity") { // deprecated. no coding
+            delById(Http::HdrType::TRANSFER_ENCODING);
+        } else {
+            // This also rejects multiple encodings until we support them properly.
+            debugs(55, warnOnError, "WARNING: unsupported Transfer-Encoding used by client: " << rawTe);
+            teUnsupported_ = true;
+        }
+
     } else if (clen.sawBad) {
         // ensure our callers do not accidentally see bad Content-Length values
         delById(Http::HdrType::CONTENT_LENGTH);
diff --git a/src/HttpHeader.h b/src/HttpHeader.h
index e3553a4..64f294a 100644
--- a/src/HttpHeader.h
+++ b/src/HttpHeader.h
@@ -140,7 +140,13 @@ public:
     int hasListMember(Http::HdrType id, const char *member, const char separator) const;
     int hasByNameListMember(const char *name, const char *member, const char separator) const;
     void removeHopByHopEntries();
-    inline bool chunked() const; ///< whether message uses chunked Transfer-Encoding
+
+    /// whether the message uses chunked Transfer-Encoding
+    /// optimized implementation relies on us rejecting/removing other codings
+    bool chunked() const { return has(Http::HdrType::TRANSFER_ENCODING); }
+
+    /// whether message used an unsupported and/or invalid Transfer-Encoding
+    bool unsupportedTe() const { return teUnsupported_; }
 
     /* protected, do not use these, use interface functions instead */
     std::vector<HttpHeaderEntry *> entries;     /**< parsed fields in raw format */
@@ -158,6 +164,9 @@ protected:
 private:
     HttpHeaderEntry *findLastEntry(Http::HdrType id) const;
     bool conflictingContentLength_; ///< found different Content-Length fields
+    /// unsupported encoding, unnecessary syntax characters, and/or
+    /// invalid field-value found in Transfer-Encoding header
+    bool teUnsupported_ = false;
 };
 
 int httpHeaderParseQuotedString(const char *start, const int len, String *val);
@@ -167,13 +176,6 @@ SBuf httpHeaderQuoteString(const char *raw);
 
 void httpHeaderCalcMask(HttpHeaderMask * mask, Http::HdrType http_hdr_type_enums[], size_t count);
 
-inline bool
-HttpHeader::chunked() const
-{
-    return has(Http::HdrType::TRANSFER_ENCODING) &&
-           hasListMember(Http::HdrType::TRANSFER_ENCODING, "chunked", ',');
-}
-
 void httpHeaderInitModule(void);
 
 #endif /* SQUID_HTTPHEADER_H */
diff --git a/src/client_side.cc b/src/client_side.cc
index 5f5a79e..000a00b 100644
--- a/src/client_side.cc
+++ b/src/client_side.cc
@@ -1600,9 +1600,7 @@ void
 clientProcessRequest(ConnStateData *conn, const Http1::RequestParserPointer &hp, Http::Stream *context)
 {
     ClientHttpRequest *http = context->http;
-    bool chunked = false;
     bool mustReplyToOptions = false;
-    bool unsupportedTe = false;
     bool expectBody = false;
 
     // We already have the request parsed and checked, so we
@@ -1659,13 +1657,7 @@ clientProcessRequest(ConnStateData *conn, const Http1::RequestParserPointer &hp,
         request->http_ver.minor = http_ver.minor;
     }
 
-    if (request->header.chunked()) {
-        chunked = true;
-    } else if (request->header.has(Http::HdrType::TRANSFER_ENCODING)) {
-        const String te = request->header.getList(Http::HdrType::TRANSFER_ENCODING);
-        // HTTP/1.1 requires chunking to be the last encoding if there is one
-        unsupportedTe = te.size() && te != "identity";
-    } // else implied identity coding
+    const auto unsupportedTe = request->header.unsupportedTe();
 
     mustReplyToOptions = (request->method == Http::METHOD_OPTIONS) &&
                          (request->header.getInt64(Http::HdrType::MAX_FORWARDS) == 0);
@@ -1682,6 +1674,7 @@ clientProcessRequest(ConnStateData *conn, const Http1::RequestParserPointer &hp,
         return;
     }
 
+    const auto chunked = request->header.chunked();
     if (!chunked && !clientIsContentLengthValid(request.getRaw())) {
         clientStreamNode *node = context->getClientReplyContext();
         clientReplyContext *repContext = dynamic_cast<clientReplyContext *>(node->data.getRaw());
diff --git a/src/http.cc b/src/http.cc
index 9654c4a..6f4d3b2 100644
--- a/src/http.cc
+++ b/src/http.cc
@@ -1292,6 +1292,9 @@ HttpStateData::continueAfterParsingHeader()
             } else if (vrep->header.conflictingContentLength()) {
                 fwd->dontRetry(true);
                 error = ERR_INVALID_RESP;
+            } else if (vrep->header.unsupportedTe()) {
+                fwd->dontRetry(true);
+                error = ERR_INVALID_RESP;
             } else {
                 return true; // done parsing, got reply, and no error
             }