diff --git a/cli-runopts.c b/cli-runopts.c
index ab25d37..8d1edee 100644
--- a/cli-runopts.c
+++ b/cli-runopts.c
@@ -538,7 +538,7 @@
 
 	if (opts.recv_window != DEFAULT_RECV_WINDOW)
 	{
-		int written = snprintf(ret+total, len-total, "-W %d ", opts.recv_window);
+		int written = snprintf(ret+total, len-total, "-W %u ", opts.recv_window);
 		total += written;
 	}
 
diff --git a/cli-tcpfwd.c b/cli-tcpfwd.c
index fec5dba..b32d9e0 100644
--- a/cli-tcpfwd.c
+++ b/cli-tcpfwd.c
@@ -273,7 +273,7 @@
 		goto out;
 	}
 	
-	snprintf(portstring, sizeof(portstring), "%d", fwd->connectport);
+	snprintf(portstring, sizeof(portstring), "%u", fwd->connectport);
 	channel->conn_pending = connect_remote(fwd->connectaddr, portstring, channel_connect_done, channel);
 
 	channel->prio = DROPBEAR_CHANNEL_PRIO_UNKNOWABLE;
diff --git a/svr-session.c b/svr-session.c
index f777b5f..254a747 100644
--- a/svr-session.c
+++ b/svr-session.c
@@ -160,7 +160,7 @@
 	} else if (ses.authstate.pw_name) {
 		/* we have a potential user */
 		snprintf(fmtbuf, sizeof(fmtbuf), 
-				"Exit before auth (user '%s', %d fails): %s",
+				"Exit before auth (user '%s', %u fails): %s",
 				ses.authstate.pw_name, ses.authstate.failcount, format);
 	} else {
 		/* before userauth */
diff --git a/svr-tcpfwd.c b/svr-tcpfwd.c
index d2f1427..9d051bf 100644
--- a/svr-tcpfwd.c
+++ b/svr-tcpfwd.c
@@ -269,7 +269,7 @@
 		goto out;
 	}
 
-	snprintf(portstring, sizeof(portstring), "%d", destport);
+	snprintf(portstring, sizeof(portstring), "%u", destport);
 	channel->conn_pending = connect_remote(desthost, portstring, channel_connect_done, channel);
 
 	channel->prio = DROPBEAR_CHANNEL_PRIO_UNKNOWABLE;
diff --git a/svr-x11fwd.c b/svr-x11fwd.c
index 144ec0b..9e7df24 100644
--- a/svr-x11fwd.c
+++ b/svr-x11fwd.c
@@ -142,7 +142,7 @@
 	}
 
 	/* create the DISPLAY string */
-	val = snprintf(display, sizeof(display), "localhost:%d.%d",
+	val = snprintf(display, sizeof(display), "localhost:%d.%u",
 			chansess->x11port - X11BASEPORT, chansess->x11screennum);
 	if (val < 0 || val >= (int)sizeof(display)) {
 		/* string was truncated */
@@ -152,7 +152,7 @@
 	addnewvar("DISPLAY", display);
 
 	/* create the xauth string */
-	val = snprintf(display, sizeof(display), "unix:%d.%d",
+	val = snprintf(display, sizeof(display), "unix:%d.%u",
 			chansess->x11port - X11BASEPORT, chansess->x11screennum);
 	if (val < 0 || val >= (int)sizeof(display)) {
 		/* string was truncated */
diff --git a/tcp-accept.c b/tcp-accept.c
index 4456920..f1f51a7 100644
--- a/tcp-accept.c
+++ b/tcp-accept.c
@@ -121,7 +121,7 @@
 	TRACE(("enter listen_tcpfwd"))
 
 	/* first we try to bind, so don't need to do so much cleanup on failure */
-	snprintf(portstring, sizeof(portstring), "%d", tcpinfo->listenport);
+	snprintf(portstring, sizeof(portstring), "%u", tcpinfo->listenport);
 
 	nsocks = dropbear_listen(tcpinfo->listenaddr, portstring, socks, 
 			DROPBEAR_MAX_SOCKS, &errstring, &ses.maxfd);