Can I hook up my own router to use the ISP'router?

My ISP supplied a router, which has very basic functionality. I did not get any username/password with it, so I assume that I can only use that particular router to access the internet.

So currently my network is as follows:

http://chaos.stw-bonn.de/users/mu/uploads/2014-03-19/1.png

I am thinking about buying a decent router where I could use openWRT for instance and set it up like so:

http://chaos.stw-bonn.de/users/mu/uploads/2014-03-19/2.png

What I expect from it would be:

See internet usage: My plan is unlimited, and the ISP does not track the usage. So I have no idea how much I use, and it interests me a little bit.
Having a decent router with a hopefully decent firewall. The cheap ISP routers are known to have little security and my one cannot be configured properly.
USB port on the router for file sharing within the network without needing a dedicated PC for this.
Second wifi which is separate from the internal one. That way, I can give internet access to guests without letting them into my private network.

Can a second router work behind the ISP router which currently gives IP addresses via DHCP?

networking

Martin Ueding

Posted 2014-03-19T12:50:52.887

Reputation: 1 857

agree with @techie007; most decent new routers are multi-band, and have a "guest" function for isolation (as in your design). The nice thing about having that all in one router is to avoid maintaining/logging in multiple routers. So disable wireless on the ISP router and just use the wired connection to your new router. – jdh – 2014-03-19T13:02:51.363

Answers

Yes, people do this all the time. :) It's extra handy when you're trying to segment a 'guest' network that's firewalled from you, as it looks like you intend to do.

Otherwise to your points, you'll just want to shop around to find the features you're looking for. Perhaps use and old PC and look into using a solution like Untagnle.com's products.

Also look into alternative router firmwares like DD-WRT.

As for DHCP:

Set the WAN of the internal router to use DHCP from the ISP's router to get its WAN/"Internet" settings. Then use the internal router's DHCP server to serve DHCP for the internal network, on a different subnet.

Ƭᴇcʜιᴇ007

Posted 2014-03-19T12:50:52.887

Reputation: 103 763

Adding an old PC will consume too much power. I would prefer to add only small amounts of extra power consumption to the network. – Martin Ueding – 2014-03-19T13:57:40.673

@queueoverflow I only suggested using a PC due to the feature-set you seem to want. Specially when it comes to bandwidth monitoring/reporting, for example, you need something kind of robust to log all the connections. Besides if you have a spare PC with a couple NICs, it's free to setup and try. :) – Ƭᴇcʜιᴇ007 – 2014-03-19T14:00:08.117

*"Especially when..." :) – Ƭᴇcʜιᴇ007 – 2014-03-19T14:10:20.167

A setup like that will work just fine, I do the same thing for the same reasons at home as well.

Some providers will give you the option to switch the device they provide to you into a bridged mode. Then it will not apply additional routing and it might potentially make your whole setup slightly less complicated.

Der Hochstapler

Posted 2014-03-19T12:50:52.887

Reputation: 77 228

I did not find the bridge mode, but I guess that is not a big problem. – Martin Ueding – 2014-03-19T13:56:09.083