What is the difference between "source station address (back-to-source address)" and "back-to-source domain name (back-to-source host header)"?  

The back-to-source address indicates the actual, accessible address of the source station, which may be an IP address or a domain name. If it's a domain name, Content Delivery Network, during the return to source, will resolve the address for the domain name and then access it via the resolved IP.

The back-to-source domain name indicates the host field value in the HTTP request header when Content Delivery Network returns to source. This field value is generally a character string in the form of a domain name. The source station uses this domain name to identify whether it is the same as the domain name that was configured on the source station.

Is the gzip feature for HTTP headers supported?

If Azure Content Delivery Network is required to support the gzip feature of an HTTP header, you must submit a work order to activate such a function. When you submit the work order, provide the acceleration domain name, the source station domain name, and the type of file that needs to be accelerated.

How do I configure CNAME?

Go to the domain name management company and find the parsing manager for the domain name. Delete the A record for the domain, and add a CNAME record. You should already have the domain name for CNAME.

How do I confirm that my CNAME record has taken effect?

The time at which Domain Name System (DNS) changes take effect varies between regions, and depends on the time at which the original record corresponding to the domain name takes effect (time to live [TTL]). If pinging (or digging) the domain name no longer resolves your source station IP, the CNAME record has already taken effect.

How do I obtain a visitor's originating IP address from the origin domain log?

After a website is accelerated by using Content Delivery Network, the vast majority of visits will come from the network cache nodes. When the Content Delivery Network returns to the source, it will enter the originating IP address in the HTTP Header X-Forwarded-For. You can edit the source station's web server log configuration so that this information is recorded.

If we take NGINX as an example, you can add the following information to the configuration file:

log_format logCDN '$remote_addr forwarded for $http_x_forwarded_for - $remote_user [$time_local]  '

'"$request" $status $body_bytes_sent '

'"$http_referer" "$http_user_agent"';

access_log /var/log/nginx/access.log logCDN;