diff --git a/libc/net/lib_inetntoa.c b/libc/net/lib_inetntoa.c
index f04c3a48ff..9e763de6b4 100644
--- a/libc/net/lib_inetntoa.c
+++ b/libc/net/lib_inetntoa.c
@@ -65,16 +65,16 @@
 FAR char *inet_ntoa(struct in_addr in)
 {
   static char buffer[INET_ADDRSTRLEN+2];
-  FAR char *ptr = (FAR char*)&in.s_addr;
-  sprintf(buffer, "%d.%d.%d.%d", ptr[0], ptr[1], ptr[2], ptr[3]);
+  FAR unsigned char *ptr = (FAR unsigned char*)&in.s_addr;
+  sprintf(buffer, "%u.%u.%u.%u", ptr[0], ptr[1], ptr[2], ptr[3]);
   return buffer;
 }
 #else
 FAR char *_inet_ntoa(in_addr_t in)
 {
   static char buffer[INET_ADDRSTRLEN+2];
-  FAR char *ptr = (FAR char*)∈
-  sprintf(buffer, "%d.%d.%d.%d", ptr[0], ptr[1], ptr[2], ptr[3]);
+  FAR unsigned char *ptr = (FAR unsigned char*)∈
+  sprintf(buffer, "%u.%u.%u.%u", ptr[0], ptr[1], ptr[2], ptr[3]);
   return buffer;
 }
 #endif