While executing gem ... (Gem::RemoteFetcher::UnknownHostError) no such name

I'm having an issue installing rails on Ubuntu 14.04.2. Basically, when I am trying to run "gem install rails -v 4.2.0 -V", it seems to fail at the same dependencies every time, and if I can resolve one dependency somehow, it will fail at another afterwards. I will show a small snippet below (the full output is on gist):

GET http://ift.tt/1N8XobC
200 OK
GET http://ift.tt/18hiwfh
200 OK
GET http://ift.tt/1N8XpfJ
302 Moved Temporarily
ERROR:  While executing gem ... (Gem::RemoteFetcher::UnknownHostError)
    no such name (http://ift.tt/1N8XpfJ)

Here is a link to my gist with the full output of where I am having the issue: http://ift.tt/18hitQv

To provide some background information, I have a fresh install of Ubuntu 14.04.2 and have only started following this guide to install Ruby/Rails: http://ift.tt/1hGmfot (I followed the "rbenv" parts of the guide, and skipped the "Configuring Git" portion, as it isn't necessary for what I am doing).

I've spoken to the community at rubygems, and I was told that "[My] DNS resolver is having a hard time resolving the AWS cache hostname". I'm not sure how to resolve this issue if it is a DNS issue.

ADDITIONAL NOTES:

I was having some trouble with another dependency earlier (mini_portile) that had the same error, and I was first told to try this command:

curl -O http://ift.tt/18hitQx

which did resolve that issue, though I'm unsure if I will have to do this for each and every dependency that has an issue?

Any help would be appreciated, thanks.