setting up mass subdomains and have immediate access to them

[kumsanto]

i managed to do this with mod_rewrite without really creating new
domains but just setting up the wild card domain and then parsing
request uri to forward request.
Kevin Darcy wrote:
> kumsanto wrote:
> > Does anyone know how for the scenarios of  blogspot or wordpress or
> > meetup subdomain URLs are generated immediately after user sign up. I
> > tried to follow methods mentioned in apache documentation
> > (http://httpd.apache.org/docs/1.3/vhosts/mass.html) and those things
> > work but it takes a while before those subdomains are visible from
> > remote computers.. i.e. after I set up user1.xxx.com and user2.xxx.com
> > , if user visits these URLs immediately there is no page available but
> > after some time these domains are available.. Any clues? Suggestions?
> >
> You might be running into a negative caching problem. If the parent
> domain has negative caching set to an hour, say, and a client queries
> the subdomain through an intermediary resolver just before it exists,
> then the NXDOMAIN that is returned may be cached by the intermediary
> resolver and it could be almost an hour before subdomain is visible to
> the client.
>
> You can "solve" this by lowering the negative caching TTL, of course,
> but that's a rather anti-social way to go about it, since it makes
> everyone else's nameservers work harder for regular resolution of
> regular names in your parent domain. It's really not a scalable solution
> to the "problem" that you're trying to solve.
>
> What I think some folks do is have a wildcard A record in the parent
> domain pointing to a web server that has the content of the new website
> (or does an HTTP-level redirect, using some established name, to a site
> that has the new content), until the DNS has enough time to propagate
> and/or the negative cache entries have enough time to expire.
>
>
>                               - Kevin