Re: Slow connections - DNS problems?
El mié, 24 mar 2021 a las 10:45, Andrei POPESCU
(<andreimpopescu@gmail.com>) escribió:
>
> On Mi, 24 mar 21, 10:34:54, tomas@tuxteam.de wrote:
> > On Wed, Mar 24, 2021 at 09:24:28AM +0000, Darac Marjal wrote:
> > >
> > > On 24/03/2021 05:32, Charlie Gibbs wrote:
> >
> > [...]
> >
> > > > # Generated by NetworkManager
> > > > search telus
> > > > nameserver 192.168.0.1
> > > > nameserver 75.153.171.122
> > > > nameserver 2001:568:ff09:10a::56
> > > > # NOTE: the libc resolver may not support more than 3 nameservers.
> > > > # The nameservers listed below may not be recognized.
> > > > nameserver 2001:568:ff09:10b::122
> > > >
> > > > My home router (supplied by Telus, notice the "search" line)
> > >
> > > Just another point to add to what other people are saying. This line
> > > looks a bit suspicious to me. The "search" line is _supposed_ to be a
> > > list of domains which your computer is part of. It's implemented such
> > > that, when the resolver is asked to look up a short name (e.g. "printer"
> > > or "my-laptop" etc), then each item in the search list will be appended
> > > in turn and a lookup made. So, for example you could have "search
> > > example.com example.net" and a lookup for "gateway" would try
> > > "gateway.example.com" then "gateway.example.net" in turn.
> >
> > [...]
> >
> > Well spotted. The "search telus" looks completely bogus, too. Unless
> > you'have set up a local DNS with the "fake" TLD telus, but then, you'd
> > probably know ;-)
>
> This was likely set up by the Telus home router and provided via DHCP to
> all local systems.
Well, I'm not pretty sure about this subject but... When I was setting up
an OpenWRT router I saw there was a thing called "local domain", it looks
like the router had a DNS that answered queries for that local top level domain,
which had the hostnames of the devices connected to the router as subdomains.
So, for example, if you had a device called "my-pc" and your local TLD
was "telus",
the writing "my-pc.telus" would send a DNS query to the router and
it will answer with the IP address of that device.
The router indeed used the DHCP to broadcast that local domain.
In order for that local domain to work, the router needed to have a DNS
server running and configured to answer such queries, the DHCP server had
to pass the device's hostnames to the DNS someway, and the router
had to be announced as a DNS server to the devices connected on LAN
by DHCP. If you override the router DNS, the local domain will not work.
Perhaps the router's DNS server redirects non-local queries to upstream servers
and maybe those DNS servers broadcasted by the DHCP are a little slow;
together, that could introduce a little delay for DNS responses. If you can,
you could try to make the router send a known fast DNS server as the first
DNS and then itself as the second DNS (if you want to keep the local domain).
As I said, I don't know too much about this, so please correct me if I'm wrong.
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