From 7d7118bde4bceeab3bbf10a56f9f92001530aa39 Mon Sep 17 00:00:00 2001
From: qkrwjdan <44994031+qkrwjdan@users.noreply.github.com>
Date: Thu, 6 Jul 2023 01:40:20 +0900
Subject: [PATCH] PYTHON-3800 Add lower() to node when validate hosts of srv
 records (#1289)

---
 pymongo/srv_resolver.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pymongo/srv_resolver.py b/pymongo/srv_resolver.py
index 57c48f1e1..67b781cf9 100644
--- a/pymongo/srv_resolver.py
+++ b/pymongo/srv_resolver.py
@@ -118,7 +118,7 @@ class _SrvResolver:
         # Validate hosts
         for node in nodes:
             try:
-                nlist = node[0].split(".")[1:][-self.__slen :]
+                nlist = node[0].lower().split(".")[1:][-self.__slen :]
             except Exception:
                 raise ConfigurationError(f"Invalid SRV host: {node[0]}")
             if self.__plist != nlist: