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Mirror Listings Though TXT DNS Records?

Posted by Cliff on from the an-interesting-idea dept.

mackman asks: "I was wondering if anyone has ever though about using their DNS servers to provide mirror information? A specially formated TXT-record could easily provide a DNS-cache-friendly mirror listing. A TXT-record would just need a list of servers and paths, or perhaps a more complicated mapping for servers which only mirror a subset of the original site. This would allow for much more flexibility than a basic round-robin A-record scheme. For example, instead of pounding the Red Hat web server to get a mirror listing (or relying on Slashdot posts for that matter), why not do a 'dig -t txt mirrors.redhat.com'? Of course we could build this into download managers like wget."

2 of 32 comments (clear)

  1. Good idea! by root+66 · · Score: 5, Insightful

    This is a very nice idea.
    But for more usability the record should include the location (country and continent) of each mirror, so your favourite download manager can try the nearest mirrors first.

    Another question is how quick such lists would be replicated/cached by your ISP's DNS server...

    --
    -- I love the smell of Blue Screens in the morning.
  2. Re:Interesting... but no by schon · · Score: 4, Insightful

    I really don't think that kind of functionality belongs in a DNS

    Exactly.

    DNS is supposed to provide nameIP mappings, in an application-neutral fashion.

    By trying to make it provide "mirror" information, you're moving into the realm of the application - which doesn't really map properly to the concept of IP address.

    The question (of course) is "mirror for what?"

    HTTP content? Why only HTTP? FTP sites are commonly mirrored as well. How do you distinguish between the two? If you do a lookup for the example provided - "mirrors.redhat.com" - which service is mirrored, the HTTP, or the FTP? How do you know if they have different content? How do you know if they have the same content? And what happens if you have multiple HTTP servers on the same machine? (Say, one running on port 80, and one running on port 8080.)

    Which one gets mirrored? Since you can't do a DNS lookup for "www.redhat.com:8080", this makes it impossible to provide a mirror for anything that doesn't use the WK port.