diff --git a/CHANGES b/CHANGES
index c612496020..300653d2c1 100644
--- a/CHANGES
+++ b/CHANGES
@@ -1,3 +1,7 @@
+6155.	[bug]		Treat ISC_R_INVALIDPROTO as a networking error
+			in the dispatch code to avoid retrying with the
+			same server. [GL #4005]<
+
 6154.	[func]		Add spinlock implementation.  The spinlock is much
 			smaller (8 bytes) than pthread_mutex (40 bytes), so
 			it can be easily embedded into objects for more
diff --git a/doc/notes/notes-current.rst b/doc/notes/notes-current.rst
index 51c5e2d9e6..0d0ada857e 100644
--- a/doc/notes/notes-current.rst
+++ b/doc/notes/notes-current.rst
@@ -35,14 +35,16 @@ Feature Changes
 Bug Fixes
 ~~~~~~~~~
 
-- None.
-
 - When the same ``notify-source`` address and port number was configured for
   multiple destinations and zones, an unresponsive server could tie up the
   socket until it timed out; in the meantime, NOTIFY messages for other servers
   silently failed.``named`` will now retry these failing messages over TCP.
   NOTIFY failures are now logged at level INFO. :gl:`#4001` :gl:`#4002`
 
+- When ISC_R_INVALIDPROTO (ENOPROTOOPT, EPROTONOSUPPORT) is returned from
+  libuv, treat it as a network failure, mark the server as broken and don't
+  try again. :gl:`#4005`
+
 Known Issues
 ~~~~~~~~~~~~
 
diff --git a/lib/dns/resolver.c b/lib/dns/resolver.c
index e472c6e78e..2564f09de0 100644
--- a/lib/dns/resolver.c
+++ b/lib/dns/resolver.c
@@ -7791,6 +7791,7 @@ rctx_dispfail(respctx_t *rctx) {
 	case ISC_R_NETUNREACH:
 	case ISC_R_CONNREFUSED:
 	case ISC_R_CONNECTIONRESET:
+	case ISC_R_INVALIDPROTO:
 	case ISC_R_CANCELED:
 	case ISC_R_SHUTTINGDOWN:
 		rctx->broken_server = rctx->result;
diff --git a/lib/isc/include/isc/result.h b/lib/isc/include/isc/result.h
index ac7273ce52..215c83aba3 100644
--- a/lib/isc/include/isc/result.h
+++ b/lib/isc/include/isc/result.h
@@ -95,6 +95,7 @@ typedef enum isc_result {
 	ISC_R_TLSBADPEERCERT, /*%< TLS peer certificate verification failed */
 	ISC_R_HTTP2ALPNERROR, /*%< ALPN for HTTP/2 failed */
 	ISC_R_DOTALPNERROR,   /*%< ALPN for DoT failed */
+	ISC_R_INVALIDPROTO,   /*%< invalid protocol */
 
 	DNS_R_LABELTOOLONG = 1 << 16,
 	DNS_R_BADESCAPE,
diff --git a/lib/isc/result.c b/lib/isc/result.c
index b41f760fa4..ac55e0bd46 100644
--- a/lib/isc/result.c
+++ b/lib/isc/result.c
@@ -94,6 +94,7 @@ static const char *description[ISC_R_NRESULTS] = {
 	[ISC_R_TLSBADPEERCERT] = "TLS peer certificate verification failed",
 	[ISC_R_HTTP2ALPNERROR] = "ALPN for HTTP/2 failed",
 	[ISC_R_DOTALPNERROR] = "ALPN for DoT failed",
+	[ISC_R_INVALIDPROTO] = "invalid protocol",
 
 	[DNS_R_LABELTOOLONG] = "label too long",
 	[DNS_R_BADESCAPE] = "bad escape",
diff --git a/lib/isc/uv.c b/lib/isc/uv.c
index 79c4362479..8b1ef7398e 100644
--- a/lib/isc/uv.c
+++ b/lib/isc/uv.c
@@ -87,13 +87,15 @@ isc__uverr2result(int uverr, bool dolog, const char *file, unsigned int line,
 		return (ISC_R_MAXSIZE);
 	case UV_ENOTSUP:
 		return (ISC_R_FAMILYNOSUPPORT);
+	case UV_ENOPROTOOPT:
+	case UV_EPROTONOSUPPORT:
+		return (ISC_R_INVALIDPROTO);
 	default:
 		if (dolog) {
-			UNEXPECTED_ERROR(
-				file, line,
-				"unable to convert libuv "
-				"error code in %s to isc_result: %d: %s",
-				func, uverr, uv_strerror(uverr));
+			UNEXPECTED_ERROR("unable to convert libuv error code "
+					 "in %s (%s:%d) to isc_result: %d: %s",
+					 func, file, line, uverr,
+					 uv_strerror(uverr));
 		}
 		return (ISC_R_UNEXPECTED);
 	}