IP address change monitor

What this test tells you

Keep this monitor open while reconnecting or changing a route to see when an observed address changes. The source matters as much as the number: a browser probe, the website's incoming connection and the server's outgoing connection can legitimately show different addresses.

How to run the test

1. Choose the observation source and a sensible sampling interval, then note whether it measures browser traffic or server egress.
2. Start monitoring and leave the tab active while you perform the connection change you want to observe.
3. Read the timestamped observations, changes and errors. Stop the monitor when finished and export the history if useful.

How the measurement works

The monitor repeatedly samples the selected source. Browser probes contact IP echo endpoints directly; the incoming server observation describes requests to this website.

The optional server egress check measures our server, which is generally a hosting machine on a public website. History and JSON export are handled in the browser rather than saved as a server history.

Understanding your results

Address changed

The same source returned a different public address. This supports a route change, reconnection or address reassignment during the observed period.

Address unchanged

The sampled source stayed stable. A brief change between samples or a change affecting another application may still have occurred.

Probe error

A timeout, browser restriction, blocker or outage interrupted measurement. An error is not an address change and should not be counted as one.

Compare before and after

1. Save a baseline using the same tab, source, IP family and sampling interval.
2. Make one intended change, such as reconnecting the VPN, while monitoring continues.
3. Compare the last reliable observation before and the first reliable observation after. Keep gaps and errors visible when explaining timing.

Limits of the test

• Background tabs may slow timers, and frequent probes can encounter provider quotas.
• IPv4 and IPv6 probes can select different families; comparing their numbers alone does not establish a leak.

What to change, if needed

The expected browser route does not change

Check the selected source and the scope of the connection setting, then repeat with the relevant browser probe.

Errors recur at short intervals

Increase the interval and check connectivity or extensions before interpreting the sequence.

Frequently asked questions

Sources and technical references

• ipify