Since I just saw yet another developer use '1.2.3.4' in an example configuration, a reminder that you MUST NOT use publicly routable addresses that you do not control in your code.

Instead, use one of the available 'TEST-NET' IPv4 or IPv6 ranges documented in RFC 6890, such as;

192.0.2.0/24
198.51.100.0/24
203.0.113.0/24

❌ 1.2.3.4
✅ 192.0.2.4

Pass it on to all of your fellow developers, documentation writers, and so forth.

Full RFC is here;

https://datatracker.ietf.org/doc/rfc6890/

RFC 6890: Special-Purpose IP Address Registries

This memo reiterates the assignment of an IPv4 address block (192.0.0.0/24) to IANA. It also instructs IANA to restructure its IPv4 and IPv6 Special-Purpose Address Registries. Upon restructuring, the aforementioned registries will record all special-purpose address blocks, maintaining a common set of information regarding each address block.

IETF Datatracker
@sindarina It's also worth making sure your company's tech writing style guide covers this and requires the use of documentation prefixes for IPv4 and IPv4 as well as proper example domains. That way tech writers can help fix things developers let slip. Always including #IPv6 examples (from 2001:db8::/32) is also worthwhile as a best practice.