diff --git a/ssnet.py b/ssnet.py
index 2abf5d0..a987562 100644
--- a/ssnet.py
+++ b/ssnet.py
@@ -124,6 +124,12 @@ class SockWrapper:
             return  # already connected
         self.rsock.setblocking(False)
         debug3('%r: trying connect to %r\n' % (self, self.connect_to))
+        if socket.inet_aton(self.connect_to[0])[0] == '\0':
+            self.seterr(Exception("Can't connect to %r: "
+                                  "IP address starts with zero\n"
+                                  % (self.connect_to,)))
+            self.connect_to = None
+            return
         try:
             self.rsock.connect(self.connect_to)
             # connected successfully (Linux)