I'm planning to use Amazon S3 with Cloudfront as CDN network.

But I'm guessing that changing the url from 345345df4.cloudfront.com to sub.domain.com will slow the process of download

Is this correct?

1 Answer 1


It will make no difference. Clients have to make a DNS lookup to convert the name to an IP address; using a CNAME might make that slightly slower, but by tens of milliseconds. The download itself uses the IP address, and will be entirely unaltered.

  • so do you think the hosting that holding the subdomain, will be affected and maybe it will affect the process also if it was slow and couldn't handle thousands of connections
    – Ahmed Janim
    Jun 8, 2011 at 6:28
  • 1
    no, DNS lookup is already highly optimised and cached and distributed in many locations including the user's computer. using a CNAME won't have any practical affect on whoever is hosting your DNS records
    – Myster
    Jun 29, 2011 at 2:09

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