I work for a cloud-delivered Next Gen Secure Web Gateway (cloud web proxy) company, and some of our users in Brazil are experiencing high latency when downloading ISOs for Kali's mirror. When they are steered through our web proxy platform to download the ISOs, they are being redirected to a mirror far from them (in France). When not using the web proxy, they are redirected to a closer mirror, and then the latency is ok.
We wanted to check with Kali's mirror admins to understand how the mirror selection takes place. Is it based on X-Forwarded-For (that we include in the request HTTP headers)? Or is it simply based on the Geo Location of the egress IPs of the user (in this case, our cloud web proxy)? Whatever the case, we suppose the GeoIP database being used by the mirror selector may be outdated or wrong for some reason.