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Register local DHCP clients to DNS

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05 Jul 2023 21:01 #102630 by clive_sherborne
Register local DHCP clients to DNS was created by clive_sherborne
Hi,
I don't understand why this is different from other routers. For example, with my BT Home Hub, when a DHCP Client registers, the router's DNS gets the hostname and IP address of that DHCP client. This means it's easy to find another device on your LAN by using its name.
But seemingly not with the Vigor. Is there some strange convoluted setting to achieve this?
It doesn't help that the DHCP Table seems to empty itself after not very long, and rarely shows clients' hostnames.
This seems a bit of a fundamental failing, but maybe I'm missing a step?
Thanks for any advice!

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10 Dec 2024 19:38 #104309 by ytene
Replied by ytene on topic Register local DHCP clients to DNS
I appreciate that this question was asked over a year ago and shows no sign of activity, but as I'm here I thought I'd share my personal experiences...

Firstly, if you'd like to continue to operate your local network-enabled devices using DHCP [as opposed to giving them static addresses outside your DHCP range but within your routers local network range] then the first thing you should consider doing is to use "Bind IP to MAC", which you will find in the "LAN" sub-Menu. As the name of the feature suggests, it means that each time a "known" MAC address requests a DHCP lease, the local DHCP server will ALWAYS give it the IP Address you specify. This solves half your challenge.

The second thing to do is to be willing to invest a little effort [and it is a tiny amount] in setting up a local DNS. Fortunately, there is an incredibly useful and trivially simple offering available in the form of PiHole, which not only gives you a fully-functional DNS, but it also gives you full - and I mean full network level ad-blocking, for all your devices. The way it works is simple - it has a "blacklist" of DNS names that are known to serve ads, or malware, or to act as data harvesting services that undermine your privacy. Each time a device on your network issues a DNS request for the FQDN of one of these services, PiHole returns "0.0.0.0" which is a null DNS address - and the requestor has no choice but to skip past that request. I put PiHole on my home network and the change was transformational... My Samsung SmartTV stopped displaying creepy ads relating to 4K movies I'd just watched, the browsing speed of my iPad and home PC more than tripled...

One of the other features of PiHole is that you can register local devices on your network... So say you have a NAS box from QNAP and you want to call this "qnap.myhouse.net"... Well, you can. Just add it to your local DNS records in Pihole [2 seconds] and you're done.

PiHole runs on a Raspberry Pi. Personally I use a 3B... I have one of those 10-way USB distribution blocks that has a mains transformer and some high-power charging ports, but it doesn't need that and just sits in one of the "regular" ports in headless mode. A Pi is trivially easy to set up and once you've done that you can run it in headless mode via SSH, or if you prefer a GUI, just enable VNC on the Pi and get yourself "RealVNC Viewer" and you're all set.

Yes, this means that you're not using your Draytek to provide local DNS services for your network. But using PiHole is more secure in many different ways. At the time of writing, you can get a Pi3B from "The Pi Hut" for £33.60 inc VAT. That, a means to power it and a microSD card to host it's Raspbian OS and you're all set...

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11 Dec 2024 15:33 #104312 by piste basher
Replied by piste basher on topic Register local DHCP clients to DNS
I ran piHole on a QNAP NAS for a while, until I found that it was blocking my access to Santander Online Banking (they seem to use something that piHole objects to). Guessing that it might be doing the same to other sites, and finding that the procedure to "allow" things was beyond my small mental capacity, I stopped using it.

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11 Dec 2024 16:08 #104313 by ytene
Replied by ytene on topic Register local DHCP clients to DNS
You make an important point - if a toolset isn't easy to use, we won't use it. And in fairness to your point, PiHole has had a few oddities when it comes to figuring out how to use some of it's features. If anyone is reading this and is curious... then you might like to know that PiHole features a quite sophisticated dashboard, on which two of the primary/default views are "Top Blocked Clients" and "Top Blocked Domains". You can click on any of the line items to get a per-event view of the underlying data... and then, next to the line item showing that a specific URL has been blocked [typically due to the "gravity" ruleset provided with the engine - and in support of Piste Basher, I had this a few times, you can simply click the "WhiteList" button and you're good to go...

Just taken a screen shot, but I see this BB isn't configured to support embedded images. But using the dashboard it's pretty simple with the latest release:-
1. Go to the dashboard [web interface]
2. Navigate one of the available options to find an access event that is being blocked [typically by the default "gravity" list].
3. From the identified example and having clicked through to the discrete event records, look for the large green button on the far right of the record, with "Whitelist" written on it.
4. Click the button
5. That's it.

And if you "get it wrong" and whitelist something you did not intend to, once updated, that button transforms to a "blacklist" button and you can simply reverse the process. Pretty bullet-proof.

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