The difference between URL forwarding and CNAME records

There is a large number of people on the explicit implicit forwarding and CNAME parsing records are not very deep research, do not know what the difference between the two, because all can be a domain name to jump to another domain name, the effect is not exactly the same?

First, what is implicit/explicit forwarding?

Take http://a.com jump to http://www.dnspod.cn for example.

implicit forwarding : Using the IFRAME framework technology, non-redirection technology; effect for the browser address bar input http://a.com Enter, open the site content is the destination address http://www.dnspod.cn site content, But the Address bar displays the current address http://a.com.

Note: When the destination address is not allowed to be nested, implicit forwarding (such as QQ space, cannot use implicit forwarding) cannot be used.

Explicit forwarding : Using the 301 redirect technology; effect for the browser address bar enter http://a.com carriage return, open the site content is the destination address http://www.dnspod.cn site content, and the address bar displays the destination address http:/ www.dnspod.cn.

Second, under what circumstances will use the CNAME record?

[If you need to point a domain name to another domain name and then provide an IP address from another domain name, you need to add a CNAME record]

The most commonly used cases of CNAME include: Do CDN, do business Post office

All in all, CNAME is an alias, used to point to that domain name of the IP, you point to the IP, you do not necessarily have access to the corresponding site, the server needs this site to allow binding the domain name, to be able to access, to use the forwarding function, obediently to add forwarding records, can not use CNAME record to replace the forwarding record. Just like you a.com did forward to https://www.dns.com, and then you put B.Com do a cname to a.com this is not allowed. Because A.com does not point to an IP address, it can cause access.

The difference between URL forwarding and CNAME records