4 ms·

Other currently reserved TLDs: https://en.wikipedia.org/wiki/Top-level_domain#Reserved_domains https://en.wikipedia.org/wiki/Top-level_domain#Reserved_doma...

gnabgib 3y ago
.example (for examples), .invalid (invalid domains), .localhost (avoids conflict with localhost hostname), .test (for tests), .local (link-local names), .onion (for Tor)
- jchw 3y ago
  Also good to reserve localhost since some system resolvers will actually resolve any subdomain of localhost as 127.0.0.1. (I think systemd-resolved does, but I know for sure glibc NSS with the nss-myhostname module does.)
  - tommiegannert 3y ago
    That's the speced behavior of localhost: > The domain "localhost." and any names falling within ".localhost." are special in the following ways: > 4. [---] Instead, caching DNS servers SHOULD, for all such address queries, generate an immediate positive response giving the IP loopback address https://datatracker.ietf.org/doc/html/rfc6761#section-6.3 https://datatracker.ietf.org/doc/html/rfc6761#section-6.3
    - globular-toast 3y ago
      I haven't figured out how to get unbound to do this. It's easy to configure dnsmasq to do it, though address=/localhost/127.0.0.1 address=/localhost/::1 I do this on my network because not every system resolver does it itself (annoyingly).
    - jchw 3y ago
      I actually did not know this was specified by a standard. That does indeed make it perplexing that not all resolvers do it.
    - NoZebra120vClip 3y ago
      Couple things here: The GP describes resolver software, which corresponds to item 6.3.3, not a caching server. This does specify the same behavior. In RFC terminology, "MUST" > "SHOULD" > "MAY", so there is some wiggle room there. 6.3.2 permits Chromium and other apps to hardcode localhost names as such, instead of using a resolver. A very popular vector for adware/malware is to take over the system resolver, or replace the DNS client configuration, so this is one reason Chromium jealously guards 127.0.0.0/8
- webstrand 3y ago
  what about .localdomain? I haven't been able to find anything standards-wise about it.
AndyMcConachie 3y ago
The IANA link is probably better. https://www.iana.org/assignments/special-use-domain-names/special-use-domain-names.xhtml https://www.iana.org/assignments/special-use-domain-names/sp...

gnabgib 3y ago

.example (for examples), .invalid (invalid domains), .localhost (avoids conflict with localhost hostname), .test (for tests), .local (link-local names), .onion (for Tor)

jchw 3y ago
Also good to reserve localhost since some system resolvers will actually resolve any subdomain of localhost as 127.0.0.1. (I think systemd-resolved does, but I know for sure glibc NSS with the nss-myhostname module does.)
- tommiegannert 3y ago
  That's the speced behavior of localhost: > The domain "localhost." and any names falling within ".localhost." are special in the following ways: > 4. [---] Instead, caching DNS servers SHOULD, for all such address queries, generate an immediate positive response giving the IP loopback address https://datatracker.ietf.org/doc/html/rfc6761#section-6.3 https://datatracker.ietf.org/doc/html/rfc6761#section-6.3
  - globular-toast 3y ago
    I haven't figured out how to get unbound to do this. It's easy to configure dnsmasq to do it, though address=/localhost/127.0.0.1 address=/localhost/::1 I do this on my network because not every system resolver does it itself (annoyingly).
  - jchw 3y ago
    I actually did not know this was specified by a standard. That does indeed make it perplexing that not all resolvers do it.
  - NoZebra120vClip 3y ago
    Couple things here: The GP describes resolver software, which corresponds to item 6.3.3, not a caching server. This does specify the same behavior. In RFC terminology, "MUST" > "SHOULD" > "MAY", so there is some wiggle room there. 6.3.2 permits Chromium and other apps to hardcode localhost names as such, instead of using a resolver. A very popular vector for adware/malware is to take over the system resolver, or replace the DNS client configuration, so this is one reason Chromium jealously guards 127.0.0.0/8
webstrand 3y ago
what about .localdomain? I haven't been able to find anything standards-wise about it.

AndyMcConachie 3y ago

The IANA link is probably better. https://www.iana.org/assignments/special-use-domain-names/special-use-domain-names.xhtml https://www.iana.org/assignments/special-use-domain-names/sp...