Re: setting up mass subdomains and have immediate access to them - DNS

This is a discussion on Re: setting up mass subdomains and have immediate access to them - DNS ; 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 ) ...

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Thread: Re: setting up mass subdomains and have immediate access to them

  1. Re: setting up mass subdomains and have immediate access to them

    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



  2. Re: setting up mass subdomains and have immediate access to them

    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




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