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Are ports 1-4999 already in use? Can we reserve a private area like 192.168/24 for IPs? Also why is there no official TLD for DNS for local domains?

by mavhc 5y ago

tomklein 5y ago
The first 1024 are reserved and you usually can freely choose the ones greater than that. You can also use .local for local domains.
- SturgeonsLaw 5y ago
  Using .local is no longer recommended since it's used for mDNS. Apple devices in particular have issues resolving .local addresses. Current best practice is to use a subdomain of a domain you control for internal stuff. Makes getting certs for internal hosts easier too if you can be bothered.
- AndyJames 5y ago
  1-1024 are reserved for root so you can still technically use them. Port 0 is the only one truly reserved/impossible to used
davidsojevic 5y ago
You can use the .local, .localhost, .example, and .test TLDs for local domains -- these are IANA reserved: https://www.iana.org/assignments/special-use-domain-names/special-use-domain-names.xhtml https://www.iana.org/assignments/special-use-domain-names/sp...
- mschuster91 5y ago
  .local is used for mDNS these days, don't use it if your network has Apple devices.
  - detaro 5y ago
    not just Apple devices, you'll find mDNS resolvers on many setups. Overrides in the hosts file might be fine, but still, I'd avoid it.
  - zinekeller 5y ago
    > don't use it if your network has Apple devices. As of now, but something about IPv6 also forced Microsoft to implement this, and some Linux distros also does this in CUPS (I know it's Apple...)
- dantiberian 5y ago
  Only .localhost, .example, .test, and .invalid are reserved for those purposes: https://datatracker.ietf.org/doc/html/rfc2606 https://datatracker.ietf.org/doc/html/rfc2606. .local is reserved, but for mDNS usage.
- tentacleuno 5y ago
  What about .arpa[0]? [0]: https://news.ycombinator.com/item?id=17093337 https://news.ycombinator.com/item?id=17093337
davweb 5y ago
.home and .corp are also kind of available. They are reserved so they won't ever be made available but aren't officially recognised as special use domains. I use .home and it's fine, but there's the occasional oddity when e.g. Chrome doesn't recognise "myserver.home" as a FQDN as ".home" isn't on its built in list of TLDs
- dijit 5y ago
  '.dev' was bought for the purpose of "never using it" but then Google went and started using it. So, there's at least _some_ precedent that previously reserved things become unreserved :(
  - weird-eye-issue 5y ago
    Yeah I don't think that's how it happened
    - dijit 5y ago
      That's literally what happened though; Heres the first result I found that talks about them opening up .dev and it literally says "Intended for internal use at Google Only". Though they don't provide additional citations, it's commonly understood that this was the reason it was acquired. https://www.searchenginejournal.com/google-opens-up-dev-domain-name-registry-to-everyone/294387/ https://www.searchenginejournal.com/google-opens-up-dev-doma...
      - detaro 5y ago
        That's quite different from reserved to be never used. And even if that had been the goal, it's still quite different than TLDs where ICANN has said they won't delegate them. (Which in turn are arguably weaker than ones that are reserved by an actual internet standard, although I suspect .home and .corp are more than poisoned enough. For $reasons the standard says .home.arpa and .corp.arpa, which nobody ever uses)
      - weird-eye-issue 5y ago
bloopernova 5y ago
My OpenWRT router uses .lan and that seems to work ok. Especially with short hostnames like pi.lan :)

Are ports 1-4999 already in use? Can we reserve a private area like 192.168/24 for IPs? Also why is there no official TLD for DNS for local domains?

by mavhc 5y ago

Are ports 1-4999 already in use? Can we reserve a private area like 192.168/24 for IPs? Also why is there no official TLD for DNS for local domains?

tomklein 5y ago

The first 1024 are reserved and you usually can freely choose the ones greater than that. You can also use .local for local domains.

SturgeonsLaw 5y ago
Using .local is no longer recommended since it's used for mDNS. Apple devices in particular have issues resolving .local addresses. Current best practice is to use a subdomain of a domain you control for internal stuff. Makes getting certs for internal hosts easier too if you can be bothered.
AndyJames 5y ago
1-1024 are reserved for root so you can still technically use them. Port 0 is the only one truly reserved/impossible to used

davidsojevic 5y ago

You can use the .local, .localhost, .example, and .test TLDs for local domains -- these are IANA reserved: https://www.iana.org/assignments/special-use-domain-names/special-use-domain-names.xhtml https://www.iana.org/assignments/special-use-domain-names/sp...

mschuster91 5y ago
.local is used for mDNS these days, don't use it if your network has Apple devices.
- detaro 5y ago
  not just Apple devices, you'll find mDNS resolvers on many setups. Overrides in the hosts file might be fine, but still, I'd avoid it.
- zinekeller 5y ago
  > don't use it if your network has Apple devices. As of now, but something about IPv6 also forced Microsoft to implement this, and some Linux distros also does this in CUPS (I know it's Apple...)
dantiberian 5y ago
Only .localhost, .example, .test, and .invalid are reserved for those purposes: https://datatracker.ietf.org/doc/html/rfc2606 https://datatracker.ietf.org/doc/html/rfc2606. .local is reserved, but for mDNS usage.
tentacleuno 5y ago
What about .arpa[0]? [0]: https://news.ycombinator.com/item?id=17093337 https://news.ycombinator.com/item?id=17093337

davweb 5y ago

.home and .corp are also kind of available. They are reserved so they won't ever be made available but aren't officially recognised as special use domains. I use .home and it's fine, but there's the occasional oddity when e.g. Chrome doesn't recognise "myserver.home" as a FQDN as ".home" isn't on its built in list of TLDs

dijit 5y ago
'.dev' was bought for the purpose of "never using it" but then Google went and started using it. So, there's at least _some_ precedent that previously reserved things become unreserved :(
- weird-eye-issue 5y ago
  Yeah I don't think that's how it happened
  - dijit 5y ago
    That's literally what happened though; Heres the first result I found that talks about them opening up .dev and it literally says "Intended for internal use at Google Only". Though they don't provide additional citations, it's commonly understood that this was the reason it was acquired. https://www.searchenginejournal.com/google-opens-up-dev-domain-name-registry-to-everyone/294387/ https://www.searchenginejournal.com/google-opens-up-dev-doma...
    - detaro 5y ago
      That's quite different from reserved to be never used. And even if that had been the goal, it's still quite different than TLDs where ICANN has said they won't delegate them. (Which in turn are arguably weaker than ones that are reserved by an actual internet standard, although I suspect .home and .corp are more than poisoned enough. For $reasons the standard says .home.arpa and .corp.arpa, which nobody ever uses)
    - weird-eye-issue 5y ago

bloopernova 5y ago

My OpenWRT router uses .lan and that seems to work ok. Especially with short hostnames like pi.lan :)