Re: DHCP and static addresses, nothing to do with Re: Who:Bookwormv.Trixie

[David Wright <deblis@lionunicorn.co.uk>]

On Fri 11 Apr 2025 at 05:45:47 (-0400), Dan Purgert wrote:
> On Apr 10, 2025, David Wright wrote:
> > > > On Thu 03 Apr 2025 at 06:55:10 (-0400), Greg Wooledge wrote:
> > > Or you use mdns, which is the standard way of dealing with dynamic
> > > resources on an unmanaged network.
> > 
> > The resources stay fixed during their lifetime, and any changes that
> > occur are at a glacial pace. The network is managed, by me.
> > 
> > I also don't like the names that mDNS comes up with.
> 
> It should just be 'hostname.local'.  But yeah, if the host defaults to a
> weirdo name (like my printer's default of  BCP[SERIALNO]), they do tend
> to get a bit unwieldy.

Too right. So I set up a cups queue with a simple name, which is
used by bash functions that select between portrait/landscape and 1s/2s.

> > > (That doesn't mean you have to use
> > > mdns, it just means that if you instead decide to do something like
> > > copy hosts files around the network you're choosing to make up your
> > > own solution to the inherent problems that led to dns in the first
> > > place.)
> > 
> > I can hardly take credit for inventing /etc/hosts. It's simple to set
> > up, and it causes no problems here. I don't think DNS was invented for
> > resolving two dozen non-hierachical names on one site.
> 
> That's exactly what DNS was invented for. Manually managing host files
> is a pain after only a few hosts.  Add one machine, and you have to
> update 5,10,20,[...] host files. 

So the last change I made was mid-November, for adding a new laptop.
I only change the DHCP when all my hosts are running. I login to
the router, add the reservation, and remove anything that has died
since the previous change, which was, as it happens, when I installed
my latest router in December 2023. I update the master file with the
same changes. I then run a script that transfers the master file
to the half-dozen hosts, edits the hosts own line to 127.0.1.1, and
prints a diff of the old and new versions. Finally a second script
does the same thing, except it overwrites all the old hosts files.

> Yes, "Domain Names" do include hierarchy (e.g. "company.tld"); but
> that's more an artifact that when RFC 1035 was written, we were already
> seeing convergence of names for common services (mail, telnet, ftp,
> etc.).

Sure, but not at this site", unless you count my adding a .corp TLD
to all my hostnames in 2018. (I think at the time that was to quieten
exim, but smarthosts may also appreciate it.)

> > > For various reasons I'd much rather configure a static IP in this
> > > situation than set up a reservation on the dhcp server. Among other
> > > things, in a small network the bespoke dhcp configuration is likely
> > > going to cause pain that can't possibly outweigh the need to
> > > reconfigure a static IP if for some strange reason it needs to change.
> > 
> > I don't know how to configure static IPs without a DHCP server when
> > there are devices that can only configure themselves by DHCP (or
> > maybe mDNS, I haven't tried). But what are the pain and the strange
> > reason?
> 
> Correct -- if a device is stupidly-configured from the factory to
> REQUIRE DHCP, then you need to use DHCP. 

Welcome to the world of consumer electronics. Their /functionality/
is certainly not stupid.

> mDNS is just a simplified name resolution tool.  It doesn't do host
> configuration for network/netmask/gateway.

No, I think it's designed just for a single network. As I said above,
I've found it useful for driverless printing, but nothing else.

> > > Mostly,
> > > to me, this falls into a weird place in wanting to use a complex
> > > solution (static dhcp reservations) without taking the relatively
> > > small additional step of just providing dns. Either go all the way
> > > and provide all the normal facilities (which these days are often
> > > baked into the router) instead of a mash-up, or go the easy route
> > > and use dynamic dhcp and mdns.
> > 
> > Apart from configuring DNS, I don't want to have to run a dedicated
> > server 24/7. And none of the 24/7 routers has had DNS capability.
> > OTOH they've all had very simple interfaces for setting up static
> > DHCP reservations.
> 
> Sounds like getting a better router would be a good idea (I mean, when
> the current one starts acting wonky).  There are (or were) a handful of
> options that could manage to update the DNS resolver when new DHCP Hosts
> were added to the network (and, likewise, static entries for non-DHCP
> hosts).  
> 
> Granted, these days, they may need *wrt or tomato firmwares, because the
> good features always seem to be the ones that go away. :(

My first router bought over here is now about 12 years old, cost $86
at Radio Shack (R.I.P), has lost its WAN port and one LAN port over
the years, but is still working. It's replacement cost $38 at Walmart
and is also still at work. The third one, which hosts the DHCP server,
cost all of $14 at Staples (clearance). So I've got great coverage
with 3 APs, and one device could die with limited degradation, so
I can't say I'm in the market for yet another, and I've see no need
for a DNS server here.

Cheers,
David.