RemoteAddrValve
always uses IP addresses. If you want to restrict by hostname, you want to use RemoteHostValve
. Note that you are using regular expressions, so you can match part of a client's hostname if you want (but it will be somewhat less secure).
Also note that if DNS resolution has been disabled on your server, you'll still be comparing against the remote client's IP address, so you probably want an IP-fallback by allowing either hostnames or IP addresses.