IP Anonymisation
IP anonymisation refers to techniques that truncate or replace IP addresses in analytics and log data before they are stored, in order to reduce identifiability. Merely encrypting or hashing an address is reversible and counts in data protection terms as pseudonymisation (Article 4(5) GDPR), not as anonymisation; whether a data set is genuinely anonymous depends on the effort it would take to re-establish a link to a person (recital 26 GDPR).
In practice
Many analytics tools offer IP anonymisation as a standard option, or now process IP addresses only in truncated form, or do not store them permanently at all. It is a simple, effective building block for more privacy-friendly web analytics (privacy by design).