On Tue 08 Apr 2025 at 13:07:34 (-0400), Michael Stone wrote: > On Mon, Apr 07, 2025 at 10:28:12PM -0500, David Wright wrote: > > On Thu 03 Apr 2025 at 06:55:10 (-0400), Greg Wooledge wrote: > > > I disagree with you here. The 127.0.1.1 address is a placeholder put > > > there by the installer for the more common case where a machine doesn't > > > have a fixed LAN IP address. Most home or workplace computers these > > > days will get their addresses from DHCP without a reservation, so their > > > internal addresses may vary. > > > > And that means that two machines can't find each other unless the DHCP > > server is also a DNS server. Or you set up and run your own. > > 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. > (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. > > But one disadvantage of your preferred approach is that the hostname > > and domain won't resolve unless the network is up. > > Nope, the stuff in /etc/hosts will resolve regardless of the state of > the network. You won't be able to connect to the address associated > with the local hostname until that address is configured on the host. Sloppy, sorry. Yes, /I/ can resolve my hostname with getent hosts, but, for example, ping can't resolve it unless I'm connected, even when systemd shows the link as UP. > 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? > And a static IP is always going to be there (eliminating the issue of > the hostname resolving to an unreachable IP). If I were using any sort > of dhcp, including with a static reservation, I'd probably use > 127.0.1.1 for the local hostname rather than any non-local IP. As I said, that's what I do. Ping likes that too. > 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. Cheers, David.
