I just setup a second router and plugged in eth1.  But there is no field for IPv4 DNS in the configuration and my docker containers don't get DNS, although weirdly, the windows VM does?  I don't understand why it's not available?

 

 

server-diagnostics-20220730-1559.zip

Edited July 30, 20223 yr by nerbonne

although it is very common for each lan adapter to offer dns settings, it is also very useless.

The "pool" of DNS servers is global and shared among all network connection (everywhere, in any os). Usually there are only 2, sometimes 3 slots.

This depends on the DNS resolver (libs) that are used by the OS.

 

People also tend to mixup routing and dns informations. Routing is strictly bound to an adapter (eg: "search for 192.168.0 on eth0",  "search for 10.0.0.0 on eth1" and "search for everything else on ..." (default route).

DNS resolvers work on top of this in a higher level of abstracation. There is no need to tell the OS on which card it should look to get "Server1" or "Server2". It will consult the routing table automatically.

 

So, although uncommon, UNRAID does it correcly. It gives you possible entries on eth0, but in reality, they belong to any card.

 

(there is a small excuse of this: Routers with many internet connection may interpretate these entries different: "if line 1 is up, use servers that are configured on line 1" and "if line 1 fails, use the entries of the next available line". But these are specials applying to mobile devices mostly. They are not standard in normal PC lans)

 

(there is another excuse: some packages like unbound or dnsmasq allow you to configure different servers based on different nets or even different domains (called "split DNS"). This is usually needed at a border gateway of a domain where the domain is used "inside" and "outside". Usually not all devices are shown to the public, so there must be an internal DNS with all the computers/devices and an external that only contains those that should be seen from the internet. The "edge" servers like mail gateways often need this split view. But again, it has nothing to do with the OS and the stuff is not even within the network config)

 

Edited July 30, 20223 yr by MAM59

5 minutes ago, MAM59 said:

although it is very common for each lan adapter to offer dns settings, it is also very useless.

The "pool" of DNS servers is global and shared among all network connection (everywhere, in any os). Usually there are only 2, sometimes 3 slots.

This depends on the DNS resolver (libs) that are used by the OS.

 

So I could just add public DNS server there in the eth0 spot and that will fix it?

Just now, nerbonne said:

 

So I could just add public DNS server there in the eth0 spot and that will fix it?

yes. feel free to add google or something, it will work as long there is a default route (and internet is working)

 

Mainly its a GUI problem.

The DNS Server settings should be in a seperate section, like the routing table below.

 

But I guess, they have put it to eth0 to show that it is a mandantory entry like the default gateway (unlike the special routes).

 

I cannot think of a graphical representation that is "politcally correct" and also fool-proof. The current implementation is ok, although somewhat misleading to people that are not really deep into networking. So we will have to live for it.

 

Ok, I got it.  There was a bit more swearing until I realized one gateway needed a "1" and the other needed a "2"...   Thanks for the help.

Having DNS only in eth0 is very misleading. If I'm not using eth0, why would I even look at that section. Just put it separately if its global to ethX.

On 11/2/2024 at 10:29 AM, N4TH4N said:

If I'm not using eth0

Unraid is designed around using eth0, it's assumed you will assign eth0 to the primary NIC.