For the KT, I am only interested in the local network, on which a web server is already running (among other things, it serves up sideloaded epubs to the KT).
It sounds as though the solution to redirecting
www.apple.com/library/test/success.html (and anything else to be bypassed) is to add a DNS server to the local network.
By the by, I wonder how many of the problems described at the current forum topic
Kobo Touch Wi-Fi connection issues are related to the response required from
www.apple.com/library/test/success.html.