request.rb in rack-2.2.7

- old
+ new

@@ -606,10 +606,10 @@
           |
           # An IPv4 address:
           (?<ip4>[\d\.]+)
           |
           # A hostname:
-          (?<name>[a-zA-Z0-9\.\-]+)
+          (?<name>[a-zA-Z0-9\.\-_]+)
         )
         # The optional port:
         (:(?<port>\d+))?
       $/x
 