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 EtherPad.

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: RFC.

* RT Ticket is tracking OPs progress on implementing the IP to X-CS mapping function