diff --git a/dlib/sockets/sockets_extensions.cpp b/dlib/sockets/sockets_extensions.cpp
index 257a31e9b..a33a8885f 100644
--- a/dlib/sockets/sockets_extensions.cpp
+++ b/dlib/sockets/sockets_extensions.cpp
@@ -26,7 +26,7 @@ namespace dlib
     {
         std::istringstream sin(full_address);
         sin >> *this;
-        if (!sin)
+        if (!sin || sin.peek() != EOF)
             throw invalid_network_address("invalid network address: " + full_address);
     }