diff --git a/test/test_networking.py b/test/test_networking.py
index 3cf587a63..d4eba2a5d 100644
--- a/test/test_networking.py
+++ b/test/test_networking.py
@@ -1152,7 +1152,7 @@ class TestYoutubeDLNetworking:
             'debug_printtraffic': True,
             'compat_opts': ['no-certifi'],
             'nocheckcertificate': True,
-            'legacy_server_connect': True,
+            'legacyserverconnect': True,
         }) as ydl:
             rh = self.build_handler(ydl)
             assert rh.headers.get('test') == 'testtest'
diff --git a/yt_dlp/YoutubeDL.py b/yt_dlp/YoutubeDL.py
index 1a2f42fe9..324f9e99c 100644
--- a/yt_dlp/YoutubeDL.py
+++ b/yt_dlp/YoutubeDL.py
@@ -4097,7 +4097,7 @@ class YoutubeDL:
                     'verbose': 'debug_printtraffic',
                     'source_address': 'source_address',
                     'timeout': 'socket_timeout',
-                    'legacy_ssl_support': 'legacy_server_connect',
+                    'legacy_ssl_support': 'legacyserverconnect',
                     'enable_file_urls': 'enable_file_urls',
                     'client_cert': {
                         'client_certificate': 'client_certificate',