[RFCI-Discuss] about CNAME (was Re: RFCI-Discuss Digest, Vol 38, Issue 2)

[Jeff Pang]

Thank you,Paul,you are pretty kind.

In fact we have aliased netease domains's MX records to other A records.Why we need to do it?I'd describe it below.

There are only two ISPs in China: Telecom,CNC (China Network Communication).South China is in control of Telecom,while North China is in control of CNC.In fact they are the same company just about 5 years ago.For the WTO destination,China gov had split this huge company into 2 companies.Now they are in the opposing relation.This situation get our email ISPs into huge trouble.Because the network connection between Telecom and CNC is limited,so we must try to get the ways to promote accessing speed for both North China people and South China people.In fact there is no effective ways,except for placing servers in both ISP's IDCs.It means we must spend more hardware investments.For example,we place one CGI server in Telecom IDC,it can get the South China people satisfied,while the North China people should be not satisfied,so we'll place the same CGI server in CNC IDC. 

We have some servers whose IPs are in South China's range,for example,1.1.1.0/24.
At the same time we have some another servers whose IPs are in North China's range,for example,2.2.2.0/24.
When a people in South request our services,for example,www.netease.com,our DNS will parse his request to our South servers,for example,1.1.1.20.While when a people in North request the same services,our DNS should parse his request to North servers,for example, 2.2.2.20.So this way do the load balance between South and North and accelerate accessing speed for both South and North people.
In general,there is no need to do a CNAME in DNS.While our '163.com' don't have the feature of 'Split DNS',only our main domain 'netease.com' have this feature.So we must alias 'mx.mail.163.com' to 'split.netease.com'.

Since we know it's a breach to RFC,we have changed it now.We have re-deployed our DNS to cancel the CNAME for MX records.Insteadly,we get the MX records refer to 'split.netease.com' directly.When you execute 'dig 163.com mx' on Linux/Unix box,you should see:

163.com.                16637   IN      MX      50 mx.mail.163.split.netease.com.

This's a correct result for all,I think.

Finally,Thanks for others too.



>P.S.  If you post on SPAM-L or other "non-technical" "spam" mailing lists, I
>would suggest trying to keep "Netease" out of view (most of the people know
>better, but a few vocal regulars would cause problems);  Here, on RFCI or any
>IETF lists, openness is likely the better route to choose.




--
Jeff Pang
NetEase AntiSpam Team
http://corp.netease.com