diff --git a/mercurial/sslutil.py b/mercurial/sslutil.py
--- a/mercurial/sslutil.py
+++ b/mercurial/sslutil.py
@@ -120,9 +120,6 @@ def wrapsocket(sock, keyfile, certfile, 
       server (and client) support SNI, this tells the server which certificate
       to use.
     """
-    if not serverhostname:
-        raise error.Abort('serverhostname argument required')
-
     # Despite its name, PROTOCOL_SSLv23 selects the highest protocol
     # that both ends support, including TLS protocols. On legacy stacks,
     # the highest it likely goes in TLS 1.0. On modern stacks, it can