When $wgSquidServers is configured with port, isConfiguredProxy will not recognize the server and thus the X-Forwarded-For field is not trusted.
|mediawiki/core||master||+62 -6||Make IP.php trust X-Forwarded-For supplied by $wgSquidServers with port|
@Nbdd0121: I am resetting the assignee of this task because there has not been progress lately (please correct me if I am wrong!). Resetting the assignee avoids the impression that somebody is already working on this task. It also allows others to potentially work towards fixing this task. Please claim this task again when you plan to work on it (via Add Action... → Assign / Claim in the dropdown menu) - it would be welcome. Thanks for your understanding!
This bug is referenced by the docs for $wgCdnServers, and I'd just commented on T291768 about needed to add port 80 to my list of Varnish servers. However, the purges seem to be working whether or not I also add the IPs to $wgCdnServersNopurge. I am on MW 1.36.2, so maybe this issue was resolved with 1.36 (or even 1.35)?