diff --git a/src/iperf.h b/src/iperf.h
index 7b270bd0f..707ca2229 100644
--- a/src/iperf.h
+++ b/src/iperf.h
@@ -67,6 +67,7 @@
 #include "queue.h"
 #include "cjson.h"
 #include "iperf_time.h"
+#include "portable_endian.h"
 
 #if defined(HAVE_SSL)
 #include <openssl/bio.h>
@@ -93,6 +94,10 @@ typedef uint_fast64_t iperf_size_t;
 typedef atomic_uint_fast64_t atomic_iperf_size_t;
 #endif // __IPERF_API_H
 
+#if (defined(__vxworks)) || (defined(__VXWORKS__))
+typedef unsigned int uint
+#endif // __vxworks or __VXWORKS__
+
 struct iperf_interval_results
 {
     atomic_iperf_size_t bytes_transferred; /* bytes transferred in this interval */
@@ -453,9 +458,15 @@ struct iperf_test
 extern int gerror; /* error value from getaddrinfo(3), for use in internal error handling */
 
 /* UDP "connect" message and reply (textual value for Wireshark, etc. readability - legacy was numeric) */
+#if BYTE_ORDER == BIG_ENDIAN
+#define UDP_CONNECT_MSG 0x39383736
+#define UDP_CONNECT_REPLY 0x36373839
+#define LEGACY_UDP_CONNECT_REPLY 0xb168de3a
+#else
 #define UDP_CONNECT_MSG 0x36373839          // "6789" - legacy value was 123456789
 #define UDP_CONNECT_REPLY 0x39383736        // "9876" - legacy value was 987654321
 #define LEGACY_UDP_CONNECT_REPLY 987654321  // Old servers may still reply with the legacy value
+#endif
 
 /* In Reverse mode, maximum number of packets to wait for "accept" response - to handle out of order packets */
 #define MAX_REVERSE_OUT_OF_ORDER_PACKETS 2
diff --git a/src/iperf_api.c b/src/iperf_api.c
index eb234030c..105be3564 100644
--- a/src/iperf_api.c
+++ b/src/iperf_api.c
@@ -4710,7 +4710,15 @@ iperf_create_pidfile(struct iperf_test *test)
 		if (pid > 0) {
 
 		    /* See if the process exists. */
+#if (defined(__vxworks)) || (defined(__VXWORKS__))
+#if (defined(_WRS_KERNEL)) && (defined(_WRS_CONFIG_LP64))
+			if (kill((_Vx_TASK_ID)pid, 0) == 0) {
+#else
+			if (kill(pid, 0) == 0) {
+#endif // _WRS_KERNEL and _WRS_CONFIG_LP64
+#else
 		    if (kill(pid, 0) == 0) {
+#endif // __vxworks or __VXWORKS__
 			/*
 			 * Make sure not to try to delete existing PID file by
 			 * scribbling over the pathname we'd use to refer to it.
diff --git a/src/iperf_client_api.c b/src/iperf_client_api.c
index 5b333694b..7ad4c939b 100644
--- a/src/iperf_client_api.c
+++ b/src/iperf_client_api.c
@@ -614,7 +614,19 @@ iperf_run_client(struct iperf_test * test)
             timeout = &used_timeout;
         }
 
+#if (defined(__vxworks)) || (defined(__VXWORKS__))
+    if (timeout != NULL && timeout->tv_sec == 0 && timeout->tv_usec == 0) {
+        taskDelay (1);
+	}
+
+    result = select(test->max_fd + 1,
+                    &read_set,
+                    (test->state == TEST_RUNNING && !test->reverse) ? &write_set : NULL,
+                    NULL,
+                    timeout);
+#else
 	result = select(test->max_fd + 1, &read_set, &write_set, NULL, timeout);
+#endif // __vxworks or __VXWORKS__
 	if (result < 0 && errno != EINTR) {
   	    i_errno = IESELECT;
 	    goto cleanup_and_fail;
diff --git a/src/iperf_udp.c b/src/iperf_udp.c
index b7aa1ebdf..5f69ee366 100644
--- a/src/iperf_udp.c
+++ b/src/iperf_udp.c
@@ -47,7 +47,6 @@
 #include "timer.h"
 #include "net.h"
 #include "cjson.h"
-#include "portable_endian.h"
 
 #if defined(HAVE_INTTYPES_H)
 # include <inttypes.h>
diff --git a/src/portable_endian.h b/src/portable_endian.h
index c3c73ffd7..dbb678992 100644
--- a/src/portable_endian.h
+++ b/src/portable_endian.h
@@ -131,7 +131,9 @@
 // the truth because we use the homebrew htonll, et al. implementations
 // that were originally the sole implementation of this functionality
 // in iperf 3.0.
+#if (!defined(__vxworks)) && (!defined(__VXWORKS__))
 #	warning platform not supported
+#endif
 #	include <endian.h>
 #if BYTE_ORDER == BIG_ENDIAN
 #define HTONLL(n) (n)