diff --git a/radius_auth.py b/radius_auth.py
index 50460950..7ac5a720 100644
--- a/radius_auth.py
+++ b/radius_auth.py
@@ -92,7 +92,7 @@ if __name__ == '__main__' :
 
     # On logue la prise sur laquelle a lieu la tentative
     openlog("radius_auth.py")
-    switch = os.getenv("NAS_IDENTIFIER", "").replace('"', '')
+    switch = os.getenv("NAS_IDENTIFIER", "").replace('"', '').split('.')[0]
     prise = (len(switch) == 6 and (switch[3] + switch[5]) or (switch + "-"))
     prise += "%02d" % int(os.getenv("NAS_PORT", 0))
     syslog("%s -> %s [%s]" % (prise, mac, msg))