SaaS DNS Records Design

This question is an extension to previously answere开发者_运维知识库d question How to give cname forward support to saas software

Sample sites - client1.mysite.com client2.mysite.com ... clientN.mysite.com

1. Create affinity by say client[1-10].mysite.com to be forwarded to europe.mysite.com => IP address.

2. Another criteria is it should have little recourse to proxy, firewall and network changes. In essence the solution I am attempting is a Data Dependent Routing (based on URL, Login Information etc.).

However they all mean I have a token based authentication system to authenticate and then redirect the user to a new URL. I am afraid that can be a single point of failure and will need a seperate site from my core app to do such routing. Also its quite some refactoring to existing code. Another concenr is the solution also may not be entirely transparent to the end user as it will be a HTTP Redirect 301.

Keeping in mind that application can be served from Load Balanced Web Servers (IIS) with LB Switch and other Network appliances, I would greatly appreciate if someone can simplify and educate me how this should be designed.

Another resource I have been looking up is - http://en.wikipedia.org/wiki/DNAME#DNAME_record

You could stick routing information into a cookie, so that the various intermediary systems can then detect that cookie and redirect the user accordingly without there being a single point of failure.

If the user forges a cookie of his own, he might get redirected to a server where he does not belong, but that server would then check whether the cookie is indeed valid, and prevent unauthorized access.