Christian Seberino wrote:
> The super-genius security guy that wrote qmail also wrote
> a paper on why CNAME is a bad idea.......
> 
> So should everyone NEVER use it?
> 
> Can you ALWAYS get the same result by just using more 
> A records???
> 
> e.g. Use 2 A records to set www.mydomain.com and mydomain.com
> to SAME IP address without CNAMEs!!!

Even djb says CNAME's are fine to use.

But there is a time when not to use it: when you have control over the
destination.

Example: you own example.net and example.com

www.example.net CNAME -> www.example.com
www.example.com A -> 10.10.10.10

*BAD*  requires to DNS lookups, when that is not required. Since you
control example.com, you know when www.example.com changes IP address

www.example.net A -> 10.10.10.10
www.example.com A -> 10.10.10.10

Correct.


debian.example.net CNAME -> ftp.us.debian.org

*CORRECT* When you don't control the destination, you have no control
over what debian.org does.

-john


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