We’re back online again, with an (in my opinion) most interesting setup: Since the ISP provided us only with a combined splitter/4-port-DSL-modem (no router or switch), we could no longer use our router and WLAN-access-point, as the router expected to be plugged into the DSL-splitter directly and use its builtin modem.
But, as we wanted WLAN and DSL and our old router/acces-point setup (the alternative model of the ISP only did WEP encryption, arrr), I just plugged the DSL-modem into one of the routers LAN-ports (not the WAN-port as usual), and connected the access-point to the router (as usual). The router happily gave out local IPs to the access-point and connected computers, local networking was a breeze.
The fun part is, that, although PPPoE (the common method of communication between DSL modem and splitter) is usually only used between the LAN-adapter of the PC and the DSL-modem, it also works with the router and access-point in between.
And it does so, even on Windows Vista! (Just connect to the WLAN, create a new PPPoE-connection, and it just works, most amazing… Of course there are some open questions about the firewall — we want to filter DSL-traffic that goes as PPPoE over the WLAN, but not the other WLAN-traffic thats local…)
Of course it works on Linux, using the pppoe-tools. I had to alter the default configuration created by pppoeconf just in one point: insert replacedefaultroute into the peers-configuration file in order to remove the default-route that exists because of the router between DSL-modem and the PC.
That setup may not be the best (well, it is stupid, to be honest, as every client has to connect by itself which takes way too much time, there is no NAT-”firewall”, it took me 3h to figure out), but it works.
