forwarded from Yuri Astrakhan:

Don't panic. I should have explained it at the meeting: the config change at this point is PHP only - no change in varnish code just yet. Which means, the X-CS header is set only for the zero-rated requests for now, so analytics should continue investigating the pending questions in EtherPadhttp://etherpad.wikimedia.org/x-cs .

BUT! We do want to make the transition to X-CS being set on ALL incoming requests from known carriers once everything else checks out, so please let us know when we can start doing that. The plan is:

* deploy Zero config pages and manage all the banner logic from there * add PHP code to determine if the banner should be shown or not based on the zero settings, not the X-CS presence. * Get an OK from Analytics that everything is OK * change varnish files to ALWAYS include X-CS from known carriers (btw, fundraiser team really wants this data - they think our IP ranges are better than GeoIP) * Finally, get OPs to switch over from ACL-based to custom lookup based IP -> X-CS mapping.

See also: * Original specification: RFChttp://www.mediawiki.org/wiki/Requests_for_comment/Zero_Architecture . * RT Ticket https://rt.wikimedia.org/Ticket/Display.html?id=4881 is tracking OPs progress on implementing the IP to X-CS mapping function