At a glance
When a customer of Analytics requests IP address anonymization, Analytics anonymizes the address as soon as technically feasible at the earliest possible stage of the collection network. The IP anonymization feature in Analytics sets the last octet of IPv4 user IP addresses and the last 80 bits of IPv6 addresses to zeros in memory shortly after being sent to the Analytics Collection Network. The full IP address is never written to disk in this case.
When you create a property, IP-address anonymization is implemented as follows:
- Google Analytics 4 (collect data from your apps and/or your website): IP-address anonymization is always enabled. With this option, you collect data from your apps using the Firebase SDKs, and collect data from your website using a global site tag that includes a Measurement ID for your web data stream.
- Universal Analytics (collect data from your website): IP-address anonymization is opt in, and is implemented as described in the "In depth" section below.
The Analytics Collection Network
When a request for ga.js, analytics.js, _utm.gif, or /collect arrives, it includes additional information in the HTTP request header (i.e. the type of browser being used) and the TCP/IP header (i.e. the IP address of the requester).