Re: apparent change in hostnames on LAN without admin intervention
On Mon 16 Dec 2019 at 13:36:27 (-0500), Jape Person wrote:
> On 12/16/19 11:39 AM, David Wright wrote:
> > On Mon 16 Dec 2019 at 10:53:02 (-0500), Jape Person wrote:
> > > On 12/16/19 12:42 AM, David Wright wrote:
> > > > On Sat 14 Dec 2019 at 13:49:25 (-0500), Jape Person wrote:
> > > > > On 12/14/19 1:24 AM, john doe wrote:
> > > ...
> > > > > > The file '/etc/resolv.conf' should let you know what TLD is sent from
> > > > > > the DHCP server.
> > > > > >
> > > > > > Debian shouldn't modify your configuration files '/etc' without your nolage.
> > > >
> > > > Depending on the packages chosen, /etc/resolv.conf is one file in /etc
> > > > that is modified by Debian. The resolvconf package lists 23 other
> > > > programs that it is designed to adjudicate between, for want of a
> > > > better term.
> > > >
> > > ...
> > >
> > > That has been my understanding, and it's why I never edit /etc/resolv.conf myself.
> > >
> > > > > > Note that the TLD '.lan' is sometime used.
> > > >
> > > > That's another choice, like .local, that could always be issued as a
> > > > real TLD at some point in the future.
> > > >
> > > > > > 1) https://www.xfinity.com/support/articles/list-of-approved-cable-modems
> > > > >
> > > > > I'm using my own router behind the modem provided by the ISP. I've
> > > > > never used a router provided by an ISP for controlling my network.
> > > > >
> > > > > I'm using a Luxul XWR-1750 which has been kept on the latest firmware
> > > > > available. Last upgrade was done early this year, long before the
> > > > > noted change in names.
> > > > >
> > > > > The router is set to provide static IP addresses and has the names of
> > > > > each of the systems associated with their MAC Addresses and IP
> > > > > Addresses.
> > > >
> > > > Can you just clarify this? My router provides static IP addresses on
> > > > the basis of the MAC addresses, all the information being typed in¹
> > > > by me. It also lists the names of the other hosts, but only because
> > > > those hosts told it their names. IOW the router (cheap, $35) doesn't
> > > > issue hostnames, nor provide a DNS service itself. It also neither
> > > > knows nor cares what the domain name of the network is.
> > > >
> > > > How much of this is the same on the router in your network?
> > > >
> > > > ¹ actually, of course, it deduces all but the last number in the
> > > > dotted quad.
> > >
> > > Yes, it's my understanding that my router does provide DNS on the
> > > local network and will provide the 208.67.222.222, 208.67.220.220
> > > OpenDNS servers or whatever the ISP provides for DNS servers,
> > > depending upon entries made in its setup pages. I do not think that it
> > > actually issues the hostnames, but it does detect whatever hostnames
> > > the devices provide and shows them associated with the IP addresses
> > > its DHCP server issues in a table. Do you think that I'm
> > > misunderstanding the arrangement? Could well be. I have ASSumed that
> > > it worked this way from the appearance of the tables in the setup
> > > software.
> > >
> > > The software running the router is licensed under Luxul Open Source Code for Programmers (GPL).
> >
> > Others will have to comment on the functionality provided by this
> > software as I'm not familiar with it.
> >
> > But a table of names doesn't convince me that your router is providing
> > a DNS service (or a domain name). My router maintains a list of names,
> > but they're not strictly hostnames unless I edit them to be so. For
> > example, when we bought our last Roku¹, it told the router it was
> > called "ROKU PREMIEREPLUS - 964" which I edited to "rokupw²", the name
> > by which I can ping it if I want to know whether it's powered up.
> >
> > Try typing
> > $ nslookup chip-nuc 192.168.1.1
> > where 192.168.1.1 is the IP address for *your* router.
> >
> > ¹ a TV streamer. ² and "rokupe" for its ethernet interface.
> >
> Okay. I reset all of the hostnames on the network to avoid using
> improper names for the domain and to correct an issue where I would
> have had a user name and hostname being the same.
>
> I did what you suggested and got the following.
>
> $ nslookup hostname 192.168.0.1
> Server: 192.168.0.1
> Address: 192.168.0.1#53
>
> Name: hostname
> Address: 192.168.0.116
>
> Note: I replaced the actual hostname with the word "hostname" in the example.
My understanding is that you do have a DNS server in the router then,
so you could avoid having to maintain lists of hostnames and IP
addresses on any of the other hosts if the router is always on.
I assume you can expand this to include the domain name, because the
default dhclient.conf appears to ask for it from the dhcp server.
But I certainly prefer to have each host know its own hostname and
domain name before it configures the network, and IIRC the default
Debian configuration is to put
127.0.1.1 hostname.domain hostname
into /etc/hosts which ensures this.
I can't really help with what changed and when, but can only point out
that people who've used .local seem to report intermittent behaviour
in various forums that google has turned up.
Cheers,
David.
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