diff --git a/CHANGES b/CHANGES
index d568f0f..ecc5b93 100644
--- a/CHANGES
+++ b/CHANGES
@@ -23,6 +23,10 @@ Corrections:
 	Corrected a typo in configure.ac that broke option --enable-openssl-base
 	Thanks to john1doe for reporting this issue.
 
+	Socat looped endlessly, not responding to SIGTERM, when a service name
+	(for port) could not be resolved.
+	Test: BAD_SERVICE
+
 Testing:
 	Prevent the TIMESTAMP tests from sporadically failing due do seconds
 	overflow
diff --git a/test.sh b/test.sh
index c0e98a3..753c656 100755
--- a/test.sh
+++ b/test.sh
@@ -15092,6 +15092,44 @@ PORT=$((PORT+1))
 N=$((N+1))
 
 
+# Test if unknown service specs are handled properly
+NAME=BAD_SERVICE
+case "$TESTS" in
+*%$N%*|*%functions%*|*%bugs%*|*%tcp%*|*%socket%*|*%$NAME%*)
+TEST="$NAME: test if unknown service specs are handled properly"
+# Try to resolve an unspecified TCP service "
+if ! eval $NUMCOND; then :; else
+tf="$td/test$N.stdout"
+te="$td/test$N.stderr"
+tdiff="$td/test$N.diff"
+da="test$N $(date) $RANDOM"
+CMD="$TRACE $SOCAT $opts - TCP:$LOCALHOST:zyxw"
+printf "test $F_n $TEST... " $N
+$CMD >/dev/null 2>"${te}" &
+pid=$!
+sleep 1
+kill -9 $pid 2>/dev/null;
+rc=$? 	# did process still exist?
+if [ $rc -ne 0 ]; then
+    $PRINTF "$OK\n"
+    if [" $VERBOSE" ]; then
+	echo "$CMD &" >&2
+    fi
+    numOK=$((numOK+1))
+else
+    $PRINTF "$FAILED\n"
+    echo "$CMD &" >&2
+    cat "${te}" >&2
+    numFAIL=$((numFAIL+1))
+    listFAIL="$listFAIL $N"
+fi
+fi # NUMCOND
+ ;;
+esac
+PORT=$((PORT+1))
+N=$((N+1))
+
+
 # end of common tests
 
 ##################################################################################
@@ -15215,6 +15253,10 @@ rc1=$?
 kill $pid0 2>/dev/null; wait
 if [ !!! ]; then
     $PRINTF "$OK\n"
+    if [" $VERBOSE" ]; then
+	echo "$CMD0 &" >&2
+	echo "$CMD1" >&2
+    fi
     numOK=$((numOK+1))
 else
     $PRINTF "$FAILED\n"
diff --git a/xio-ip.c b/xio-ip.c
index d1e8bec..289c68e 100644
--- a/xio-ip.c
+++ b/xio-ip.c
@@ -238,6 +238,16 @@ int xiogetaddrinfo(const char *node, const char *service,
 	   continue;
 	}
 	if (error_num == EAI_SERVICE && protocol != 0) {
+	   if (hints.ai_protocol == 0) {
+	      Error7("getaddrinfo\"%s\", \"%s\", {%d,%d,%d,%d}, {}): %s",
+		     node?node:"NULL", service?service:"NULL",
+		     hints.ai_flags, hints.ai_family,
+		     hints.ai_socktype, hints.ai_protocol,
+		     gai_strerror(error_num));
+	      if (res != NULL)  freeaddrinfo(res);
+	      if (numnode)  free(numnode);
+	      return STAT_NORETRY;
+	   }
 	   hints.ai_protocol = 0;
 	   continue;
 	}