diff --git a/CHANGES b/CHANGES
index 7a88bb16d9..ab02767e73 100644
--- a/CHANGES
+++ b/CHANGES
@@ -1,3 +1,6 @@
+3638.	[cleanup]	Add the ability to handle ENOPROTOOPT in case it is 
+			encountered. [RT #34668]
+
 3637.	[bug]		'allow-query-on' was checking the source address
 			rather than the destination address. [RT #34590]
 
diff --git a/lib/isc/unix/socket.c b/lib/isc/unix/socket.c
index 00881256af..be713d67c1 100644
--- a/lib/isc/unix/socket.c
+++ b/lib/isc/unix/socket.c
@@ -1845,6 +1845,10 @@ doio_recv(isc__socket_t *sock, isc_socketevent_t *dev) {
 		/* HPUX 11.11 can return EADDRNOTAVAIL. */
 		SOFT_OR_HARD(EADDRNOTAVAIL, ISC_R_ADDRNOTAVAIL);
 		ALWAYS_HARD(ENOBUFS, ISC_R_NORESOURCES);
+		/* Should never get this one but it was seen. */
+#ifdef ENOPROTOOPT
+		SOFT_OR_HARD(ENOPROTOOPT, ISC_R_HOSTUNREACH);
+#endif
 		/*
 		 * HPUX returns EPROTO and EINVAL on receiving some ICMP/ICMPv6
 		 * errors.