DNS with FB7590 issues

2025-02-13

As one of my projects for the Homelab, I will be running a local DNS server, for name resolution of the local home.ebkozlab.nl domain. And as one might expect, this was no plug and play exercise.

Installing and configuring the DNS server was not all that difficult, following the excellent tutorial video by Christian Lempa (see youtube : You want a real Name Server at home? // DNS. Also, take a look on his channel for more nice tutorials about homelabbing).

The FB7590 side of the story

As it turns out, I needed to change some things it the setting of my router, the Fritzbox FB7590. If you have a FB type of router, this should also apply for other versions, but the location of the settings can be different.

First of all, you need to have your DNS settings correct. There are two DNS settings pages in the FB, one for the ISP outgoing requests and one for the Internal request. The first can be found under the Internet ⯈ Account settings, and the second we're interested in, under Home Network ⯈ Network.

IPv4 Settings

We are going to change the settings for IPv4 for our home network. Go to Home Netwrok ⯈ Network, the select the tab Network Settings. Scroll down to Additional Settings and click on it. Now the additional settings will be displayed. Again, scroll down further, to the section IP Addresses and click on IPv4 Settings.

DNS server address

Please note: the DNS server must have a IP address in the network segment range, that is managed by the FB in your home network. E.g., if the FB manages the range 192.169.1.0/24, your DNS server's IP address could be something like 192.168.1.29.

We now need to assign our newly created DNS server as the local DNS server. At the end of the Home Network section, you will find the entry for the DNS server. Enter the correct IP address for the new DNS server here. You will be asked to confirm your changes, by entering a number sequence on a to the FB connected phone.

The new DNS settings will only take affect, when the DHCP lease from the FB has expired and renewed. Standard, this lease is valid for 10 days on the FB7590. If you want to renew it immediately, you will have to reboot or reconnect your device.

FB hostname

If you assigned a hostname in zone file of your local DNS, you will get a connection error, as displayed below. This is, as stated here, a security issue. Luckily, the same message also gives us the solution.

...
Your FRITZ!Box's DNS rebind protection rejected your query for reasons of security.

The host header of your query is different from the name of the FRITZ!Box.

If you want to access the FRITZ!Box using another host name, please add this name as an exception in the
"DNS Rebind Protection" area of the "Home Network > Network > Network Settings" in the FRITZ!Box user interface.

As suggested, enter the FQDN name for your FB, that you have chosen in your DNS zone file. E.g., if the name you have chosen is "gateway", and your DNS is responsible for "home.yourdomain.com", your FQDN would be "gateway.home.yourdomain.com".

This "area" or field, can also be found under the Additional Settings section. Once you have entered your FB's FQDN in there and applied the changes, you can now access your FB under this new name. If it does not work, you can still use the IP address of the FB and check your settings for mistakes.