diff --git a/src/net.c b/src/net.c
index c354c8b..665430b 100644
--- a/src/net.c
+++ b/src/net.c
@@ -337,7 +337,7 @@ set_tcp_options(int sock, int no_delay, int mss)
 /****************************************************************************/
 
 int
-setnonblocking(int fd)
+setnonblocking(int fd, int nonblocking)
 {
     int flags, newflags;
 
@@ -346,7 +346,10 @@ setnonblocking(int fd)
         perror("fcntl(F_GETFL)");
         return -1;
     }
-    newflags = flags | (int) O_NONBLOCK;
+    if (nonblocking)
+	newflags = flags | (int) O_NONBLOCK;
+    else
+	newflags = flags & ~((int) O_NONBLOCK);
     if (newflags != flags)
 	if (fcntl(fd, F_SETFL, newflags) < 0) {
 	    perror("fcntl(F_SETFL)");
diff --git a/src/net.h b/src/net.h
index 81e45de..48e9275 100644
--- a/src/net.h
+++ b/src/net.h
@@ -18,7 +18,7 @@ int has_sendfile(void);
 int Nsendfile(int fromfd, int tofd, const char *buf, size_t count) /* __attribute__((hot)) */;
 int getsock_tcp_mss(int inSock);
 int set_tcp_options(int sock, int no_delay, int mss);
-int setnonblocking(int fd);
+int setnonblocking(int fd, int nonblocking);
 
 #define NET_SOFTERROR -1
 #define NET_HARDERROR -2