Debian install is asking me for my "domain name". What's my domain name and how do I find it?

[AByteSlow]

Just started installing Debian and it's asking me for my domain name (the part of my internet address to the right of my host name.

 

How do I find out what my domain name?

[Alex Atkin UK]

Your router might define one, but in general you don't have one and .local is safe to use if in doubt.  Its mostly an option so if you have any servers on that machine they know what name to send back in the response.

 

Its probably also used as a fallback if you enter an unknown name.  For example web browsers used to use it (before they defaulted to web search) so you could just use the hostname to access a server on your LAN.

 

For example mine is .lan and my NAS is called server.lan, but I only need to type in server to access it as all my clients are defined in the routers DHCP static leases which is also used for local DNS.  So when I type in server my Linux client will automatically add .lan (completely invisible to me) before doing the DNS lookup.

Unfortunately as I set mine up before .local became a standard, this doesn't work in web browsers as they do not recognise .lan as a valid domain name so initiate web search instead.  I believe they DO work for .local though.

[AByteSlow]

8 minutes ago, Alex Atkin UK said:

Your router might define one, but in general you don't have one and .local is safe to use if in doubt.  Its mostly an option so if you have any servers on that machine they know what name to send back in the response.

 

Its probably also used as a fallback if you enter an unknown name.  For example web browsers used to use it (before they defaulted to web search) so you could just use the hostname to access a server on your LAN.

 

For example mine is .lan and my NAS is called server.lan, but I only need to type in server to access it as all my clients are defined in the routers DHCP static leases which is also used for local DNS.  So when I type in server my Linux client will automatically add .lan (completely invisible to me) before doing the DNS lookup.

Unfortunately as I set mine up before .local became a standard, this doesn't work in web browsers as they do not recognise .lan as a valid domain name so initiate web search instead.  I believe they DO work for .local though.

Gotcha, so if I made it something like "localhost.local" it wouldn't mess up everyone else's wifi?

[brwainer]

25 minutes ago, AByteSlow said:

Gotcha, so if I made it something like "localhost.local" it wouldn't mess up everyone else's wifi?

Never use “localhost” as part of a name, but otherwise yes. 

[Alex Atkin UK]

For the record, the reason we don't use localhost is because EVERY PC is called localhost for its internal networking. (anything that goes over the networking stack but doesn't leave the local PC)

 

There's a lot of things that will talk over the networking stack (the software part of the network) to each other but normally be completely denied access from your LAN, for security.  Its also a good way to test the network stack is functioning correctly if you're having networking problem, as if you can talk to localhost you know the stack is fine.

[brwainer]

6 hours ago, Alex Atkin UK said:

For the record, the reason we don't use localhost is because EVERY PC is called localhost for its internal networking. (anything that goes over the networking stack but doesn't leave the local PC)

 

There's a lot of things that will talk over the networking stack (the software part of the network) to each other but normally be completely denied access from your LAN, for security.  Its also a good way to test the network stack is functioning correctly if you're having networking problem, as if you can talk to localhost you know the stack is fine.

Yep, some things you really wouldn't expect to be "networked" are easier to make that way. For example, an Antivirus program needs to have components that are at a very low level (directly inspecting other application's memory) and then the rest of it like doing the updates and providing the user an interface is at a high level. Some of them make this as completely separate elements that talk to each other over the internal localhost aka loopback networking.