[dba-Tech] Domain Redirection

Hello All,

I have a question related to CNAMEs, A Records and DNS.

I have a site that hosts 20 sites.
Customers site is www.example.com
Customer currently points his A record to my IP address
Customer points his CNAME to his domain
(This is the usual configuration for most domains)

My site is www.hostingsite.com

My problem is if I change IP address, I have to ask 20 customers to update
their DNS details.  Not Easy!

I have created a CNAME on my site named portals.hostingsite.com
I will ask all customers to change their CNAME To point instead to
portals.hostingsite.com

This means that www.example.com will be re-directed to
portals.hostingsite.com.  My server will then serve the site.

This all works well today, got CNAMES.

However...

The A record is not so easy. You cannot point an A record to a CNAME.  It
must point to an IP address.

The reason I am posting all this here is to ask you what you think about
this topic.

There is a company http://wwwizer.com/naked-domain-redirect that offer A
record re-direction for free.  Do you think there is anything wrong with
re-directing A records via a company I am not familiar with ?

thanks as always for your advice

Mark