diff --git a/src/iperf_server_api.c b/src/iperf_server_api.c
index 31b642e..5d3e3c2 100644
--- a/src/iperf_server_api.c
+++ b/src/iperf_server_api.c
@@ -534,8 +534,14 @@ iperf_run_server(struct iperf_test *test)
 			    FD_SET(s, &test->read_set);
 			if (s > test->max_fd) test->max_fd = s;
 
-			// If the protocol isn't UDP, set nonblocking sockets
-			if (test->protocol->id != Pudp) {
+			/* 
+			 * If the protocol isn't UDP, or even if it is but
+			 * we're the receiver, set nonblocking sockets.
+			 * We need this to allow a server receiver to
+			 * maintain interactivity with the control channel.
+			 */
+			if (test->protocol->id != Pudp ||
+			    !test->sender) {
 			    setnonblocking(s, 1);
 			}
 
diff --git a/src/iperf_udp.c b/src/iperf_udp.c
index edc1721..5bb8afe 100644
--- a/src/iperf_udp.c
+++ b/src/iperf_udp.c
@@ -63,7 +63,12 @@ iperf_udp_recv(struct iperf_stream *sp)
 
     r = Nread(sp->socket, sp->buffer, size, Pudp);
 
-    if (r < 0)
+    /*
+     * If we got an error in the read, or if we didn't read anything
+     * because the underlying read(2) got a EAGAIN, then skip packet
+     * processing.
+     */
+    if (r <= 0)
         return r;
 
     sp->result->bytes_received += r;