Planetarion Forums

JetLinus · 14 Oct 2004, 17:33

Ok, this is not because I'm paranoid (well, I am, but that's not the point).
Situation:
3 students living in a house in the netherlands.
They've got DSL. The modem which came with it turns out to be a router (which I'll refer to as Router #1), with only 1 socket. After this, a device for Voice-over-IP-Internet-Telephone-Stuff has to be put. It has got an analoge socket for a normal phone, and acts itself as a normal router (I call it Router #2). The nice thing is that it's got QoS, so if you're using VoIP while downloading, the speech-data will get higher priority. Unfortunately it's only a 10mbit router, but that doesn't matter.
The final device now is a wireless router that distributes the internet to the 3 student's machines and laptops respectively.
The whole setup is nice, I like the VoIP stuff and the fact that QoS comes into place BEFORE the wireless router, so there'll always be enough bandwidth for phonecalls.

The whole problem now is that I couldn't get it all to work :-/

I tried to plug in the routers one by one to configure them first. They've all got DHCP servers, which COULD confuse something, but actually, every router should have its INTERNAL side connected to the EXTERNAL side of the next one, no?

Anyway, the real problem turns out to be the first dsl-modem-router. I don't have the model name at hand now.
It works - the PC connected to it has internet. DHCP works, and I can access its web configuration interface. A problem seems to be that apparently all inside UDP traffic is blocked. And I can't find an option to enable it.

One way would be:
Router 1 sets Router 2 as its DMZ (demilitarized zone = everythings gets forwarded), then Router 2 sets Router 3 as DMZ, and Router 3 does the actual "firewalling".
I took into account that all the routers need to get different IPs etc.

However, there is no "DMZ" option in Router 1. I can use NAT, and a special thing called "Multiple NAT", which is also described as "transparent NAT" or "NAPT" or something in the manual.
What does it do?

There is an option in the NAT section called "Default Server", which should be similar to DMZ. But the Phone Router 2 thingy still couldn't find the VoIP server (which made me thinking that UDP can't pass through).

I then tried to disable various DHCP servers and assigned static IPs for the router WAN Ports (so that I could setup NAT rules). But didn't really work.

The real questions I got now:

- Do you know of any diagnostic software? I.e. that tests if inside UDP / TCP can come in, or if outside connections work? That tells you DHCP setting or scans the network for routers?

- How do I use routing tables? What are they? The dsl-modem-router 1 has got one, and my last hope would be that there might be the key. Any explanation, or lines that I could add?

Any information or hints is greatly appreciated. For more details I'll have to have a look at the devices tomorrow.

SYMM · 14 Oct 2004, 18:06

Can't help with any of the specifics, but routing tables are just lookups, that the router uses to decide where (if there are options) an incoming packet should be outputted.
With just a one-in, one-out there shouldn't be anything to change...