Tutorials or other documentation that need example IPv4 addresses should choose them from the RFC 5737 blocks reserved for this purpose. These blocks are planned to never be assigned for actual usage (including internal usage) and are intended to be filtered everywhere at firewalls & routers.
One specific practice that would prevent this:
Tutorials or other documentation that need example IPv4 addresses should choose them from the RFC 5737 blocks reserved for this purpose. These blocks are planned to never be assigned for actual usage (including internal usage) and are intended to be filtered everywhere at firewalls & routers.
192.0.2.0 − 192.0.2.255
198.51.100.0 − 198.51.100.255
203.0.113.0 − 203.0.113.255