Version
v22.22.0
Platform
Linux shy-matx 6.12.107+deb13-amd64 #1 SMP PREEMPT_DYNAMIC Debian 6.12.107-1 (2026-08-29) x86_64 GNU/Linux
Subsystem
No response
What steps will reproduce the bug?
node -e 'fetch("http://cnylon.localhost")'node:internal/deps/undici/undici:14902
Error.captureStackTrace(err);
^
TypeError: fetch failed
at node:internal/deps/undici/undici:14902:13
at process.processTicksAndRejections (node:internal/process/task_queues:105:5) {
[cause]: Error: getaddrinfo ENOTFOUND cnylon.localhost
at GetAddrInfoReqWrap.onlookupall [as oncomplete] (node:dns:122:26) {
errno: -3008,
code: 'ENOTFOUND',
syscall: 'getaddrinfo',
hostname: 'cnylon.localhost'
}
}
How often does it reproduce? Is there a required condition?
always
What is the expected behavior? Why is that the expected behavior?
https://www.rfc-editor.org/rfc/rfc6761.html#section-6.3
6.3 Domain Name Reservation Considerations for "localhost."
The domain "localhost." and any names falling within ".localhost."
are special in the following ways:
1. Users are free to use localhost names as they would any other
domain names. Users may assume that IPv4 and IPv6 address
queries for localhost names will always resolve to the respective
IP loopback address.
2. Application software MAY recognize localhost names as special, or
MAY pass them to name resolution APIs as they would for other
domain names.
3. Name resolution APIs and libraries SHOULD recognize localhost
names as special and SHOULD always return the IP loopback address
for address queries and negative responses for all other query
types. Name resolution APIs SHOULD NOT send queries for
localhost names to their configured caching DNS server(s).
4. Caching DNS servers SHOULD recognize localhost names as special
and SHOULD NOT attempt to look up NS records for them, or
otherwise query authoritative DNS servers in an attempt to
resolve localhost names. Instead, caching DNS servers SHOULD,
for all such address queries, generate an immediate positive
response giving the IP loopback address, and for all other query
types, generate an immediate negative response. This is to avoid
unnecessary load on the root name servers and other name servers.
What do you see instead?
sudo echo '127.0.0.1 cnylon.localhost' >> /etc/hosts
Additional information
deno also don't support this
Version
v22.22.0
Platform
Subsystem
No response
What steps will reproduce the bug?
node -e 'fetch("http://cnylon.localhost")'How often does it reproduce? Is there a required condition?
always
What is the expected behavior? Why is that the expected behavior?
https://www.rfc-editor.org/rfc/rfc6761.html#section-6.3
What do you see instead?
sudo echo '127.0.0.1 cnylon.localhost' >> /etc/hosts
Additional information
deno also don't support this