Funny network behaviour :)

[PatrickBaer]

A little riddle for everyone. I am really stumped and have no idea why that happens.

So here we go:

I have a Wifi setup with five APs without authentication. They are connected to the WAN via an SMC gateway, which does web-based password authentication. so the procedure is: Customer connects to an SSID and gets an IP-adress via DHCP, enters some URL and gets forwarded to the login-page, enters his personal login-data, can browse the web.

The internal setup is like this:

Gateway and default router is 172.16.0.1
Static IPs are ranged from 172.16.0.2 through 172.16.0.127
DHCP adress range is from .128
APs have a static IP-adress from 172.16.0.11 for AP1 .12 for AP2 and so on.
All devices have netmask 255.255.0.0!

As the IP range is obviously not routed outside the internal network, the administration-machine is connected via LAN to the internal network. When plugging in, the admin-machine gets an IP-adress via the gateway, e.g. 172.16.0.130 netmask 255.255.0.0 default gateway 172.16.0.1. The machine can login via web-interface and then access the external net. So far so good.

Now I want to connect to the other APs and configure them via http. And this is where the fun begins:

A simple ping results in a timeout to all devices except the gateway itself. So I thought about some setup failure and used a static IP-adress like 172.16.0.4.

Still, no responses to pings. Now, I did a broadcast ping to 172.16.255.255 and voila, APs 1 through 4 came responded! Number 5 remained silent. From that point on, I could access the APs via http also, even AP5, although it still did not respond to any ping.

Suddenly, AP5 stopped responding to http requests. So I did another broadcast ping. AP5 still not responded to the ping, but came back answering http-requests! Actually, as long as i kept pinging, the AP5 was ok, without the ping it remained silent.

After some minutes, the authentication on the APs timed out and I needed to reauthenticate. But when entering the IP into the browser bar, it did not connect, but instead forward to an adress like http://http.172.16.0.11

I think this has something to do with my internal network setting switching from the class B network to a class D and hence passing the IP to the router instead of staying in his own range.

Can someone explain this?

BTW, I also connected another laptop with ubuntu And did a broadcast ping, which showed some APs as well, but not all, like BSD did!

Oh, and if I connect to the APs with a direct connection, they work just fine.