diff --git a/src/SmtpServer/Mail/Mailbox.cs b/src/SmtpServer/Mail/Mailbox.cs
index 2175c49..5800820 100644
--- a/src/SmtpServer/Mail/Mailbox.cs
+++ b/src/SmtpServer/Mail/Mailbox.cs
@@ -44,5 +44,10 @@ public Mailbox(string address)
         /// Gets the host server.
         /// </summary>
         public string Host { get; }
+
+        public override string ToString()
+        {
+            return User + "@" + Host;
+        }
     }
-}
+}
\ No newline at end of file