On Wed, 30 Sep 2026 10:53:38 -0400 Stefan Monnier <[email protected]> wrote:
> > What's the 'right' way to set a system's domain name permanenty > > (i.e. doesn't get lost when you reboot) on Debian systems? > > Over the years, I've grown to realize tat this is fundamentally > ill-defined: the domain name is the way to find the IP address of a > host you want to connect to. The machine itself doesn't necessarily > have/need/use that info: some machines don't have any domain name, > some have several, the domain name(s) can change without the machine > being told, ... > > IME, most cases where a piece of software wanted to know "the host's > domain name" it was either "wrong" (it didn't actually need to know) > or it could use any "unique enough" name. So it might be worth > digging further into your problem to see if you can push it > elsewhere: instead of "set[ting] the system's domain name", make sure > the software doesn't need that domain name. > I think what confuses the issue is that many people come to Linux from Windows (I did) and the professional branch of Windows abuses the word 'domain' to mean a security grouping of computers, which is now actually a Kerberos realm. After NT4 it became congruent with a DNS domain, but has no real functional connection. Every computer in (or a client of) a Windows domain must be 'in' the domain, and have the relevant security keys installed. I've been out of touch with Windows since Server 2008, but at that time a workstation could only be a client of one domain, it had to be un-joined from the domain if it became necessary for it to join a different one. For a single Linux computer, 'domain' only has any relevance to email. Even when the computer becomes part of a group behind NAT, it doesn't need to have a 'domain' unless it is to be individually addressed from outside the network. Even then, its own software generally doesn't need to know what domain name was used to connect to it. Domestic Windows used hostnames, workgroups and the WINS service to keep track of what was where, never getting involved with DNS other than to look up external services. Only email clients have to know the domain, and they can often have accounts on multiple domains. -- Joe
