domain validators allows underscores

>>> import validators
>>> validators.domain('ex_ample.com')
True

The domain validator allows underscores in the name while this is illegal.

See page 8 of rfc1035

The labels must follow the rules for ARPANET host names. They must
start with a letter, end with a letter or digit, and have as interior
characters only letters, digits, and hyphen. There are also some
restrictions on the length. Labels must be 63 characters or less.

or wikipedia

A domain name consists of one or more labels, each of which is formed from the set of ASCII letters, digits, and hyphens (a–z, A–Z, 0–9, -), but not starting or ending with a hyphen. The labels are case-insensitive; for example, 'label' is equivalent to 'Label' or 'LABEL'. In the textual representation of a domain name, the labels are separated by a full stop (period).

rfc_2782 talks about prepending underscores.

This document obsoletes RFC 2052. The major change from that
previous, experimental, version of this specification is that now the
protocol and service labels are prepended with an underscore, to
lower the probability of an accidental clash with a similar name used
for unrelated purposes.

The symbolic name of the desired service, as defined in Assigned
Numbers [STD 2] or locally. An underscore (_) is prepended to
the service identifier to avoid collisions with DNS labels that
occur in nature.

The symbolic name of the desired protocol, with an underscore
(_) prepended to prevent collisions with DNS labels that occur
in nature.

Also, even if not a "standard" most modern browsers allow it.

Refer:

Navigation Menu

Repository navigation

domain validators allows underscores #340

Metadata

Assignees

Labels

Type

Projects

Milestone

Relationships

Development

domain validators allows underscores #340

Description

Activity

nandgator commented on Mar 22, 2024

Metadata

Metadata

Assignees

Labels

Type

Projects

Milestone

Relationships

Development

Issue actions