diff -r 8403cc54bc83 -r dd3050227a84 mercurial/hgweb/server.py
--- a/mercurial/hgweb/server.py	Sun Jul 05 13:09:22 2020 +0200
+++ b/mercurial/hgweb/server.py	Mon Jul 06 22:02:50 2020 -0400
@@ -382,7 +382,7 @@
         self.errorlog = elog
 
         self.addr, self.port = self.socket.getsockname()[0:2]
-        self.fqaddr = socket.getfqdn(addr[0])
+        self.fqaddr = self.server_name
 
         self.serverheader = ui.config(b'web', b'server-header')