How do cloud instance domain names work?

Discussion in 'Networking & Security' started by wizdum, Dec 30, 2014.

  1. wizdum

    wizdum [H]ard|Gawd

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    I have been playing around with Microsoft's Azure and starting thinking about how DNS resolution works with all these "cloud" providers. If I start up 10 different virtual servers (that are not web servers), I get 10 different domain names (mystuff.cloudapp.net, mystuff.blob.core.microsoft.net, etc.). They can't be giving out a public IP for each one of these domains, right? That would get expensive quickly. Port forwarding can be used to map ports on a public IP address to different internal servers, but then everyone would need to use a different, non-standard port for their service. Are they somehow pointing public domain names at private IP addresses (with something in the middle to properly route them)?

    Or do they just have a metric-frack-ton of IP addresses so they can afford to hand them out like candy?
     
  2. JTY

    JTY 2[H]4U

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    They've got a ton of IPs.
     
  3. wizdum

    wizdum [H]ard|Gawd

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    Damnit. Why can't reality be as interesting as the world inside my head.
     
  4. EricGRIT

    EricGRIT [H]Lite

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    Host headers? That's how I run multiple sites off my single IP at home.
     
  5. wizdum

    wizdum [H]ard|Gawd

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    Yeah, I have been doing that with websites. I was hoping there was a similar method for running other types of services (email, FTP, databases, game servers, etc.) as well. The way it worked in my head is this: vm1.mysite.com, vm2.mysite.com, vm3.mysite.com, etc all point to 10.10.10.10. 10.10.10.10 is running a DNS and routing service that "knows" vm1.mysite.com needs to point to 192.168.1.50, vm2.mysite.com points to 192.168.1.51, etc.
     
  6. Jay_2

    Jay_2 2[H]4U

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    Reverse proxy is also a good way.
     
  7. /usr/home

    /usr/home [H]ardness Supreme

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    This.
     
  8. Grentz

    Grentz [H]ard as it Gets

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    Most of it is proxy. I am more familiar with aws where you can choose only an internal IP to your instance or a true public IP.