diff --git a/aiosmtpd/smtp.py b/aiosmtpd/smtp.py
index 3b85fcfb..25b19bae 100644
--- a/aiosmtpd/smtp.py
+++ b/aiosmtpd/smtp.py
@@ -155,7 +155,7 @@ def __repr__(self) -> str:
 @public
 class Session:
     def __init__(self, loop: asyncio.AbstractEventLoop):
-        self.peer: Optional[str] = None
+        self.peer: Optional[Tuple[str, int]] = None
         self.ssl: Optional[dict[str, Any]] = None
         self.host_name: Optional[str] = None
         self.extended_smtp = False