WLAN router doesn't provide fix IP addresses

["B. M." <b-misc@gmx.ch>]

Hi list,

I have a problem with my (w)lan setup.
We use telephone and internet over the cable network and the company gives us a wlan modem for free. Unfortunately this modem doesn't allow me to specify fix IPs in the internal network for all of our machines.

Nevertheless I setup an owncloud server on one machine (which is somehow our "server" but not always running), including SSL encryption with a self-signed certificate for its IP address. That worked well for a couple of months because the IP addresses didn't change (although they were not fixed).

Now due to a technical problem our modem got replaced all of the IP addresses changed. (I did expect that for sometime in the future... but not so early...)

Since it's impossible to manually define the IP addresses, I've a problem. Of course I could create a new certificate, put it on all other machines and adjust all settings (owncloud server address...); but that's quite an hassle.

So I wanted to ask if there are other possibilities? I can define one or two DNS server in the modem's config. Would it work to setup my main machine (which is not always running) as an internal DNS server and use the hostnames instead of the IP addresses?

Thanks for any pointers to how I can proceed.