Let me add a bit to what /u/rackerhacker said.
Collaboration and communication are very important skills for any role, but especially for entry level technical positions. You won't be expected to know the answer to every problem that comes your way, so being willing to admit that you don't know is a valuable asset that will help in any position.
Attitude is just as important as aptitude here. Every team is a bit different in the specifics of their interview process, but a general constant is that we look for a good culture fit as an important part of the whole. I would suggest taking a look at our core values if you haven't already. They tend to be much more than just words on a wall around here and should give you some insight into the culture you can expect.
One last piece of advice I would give is that there are many teams who may be hiring Linux admins, so if you don't get in on your first try don't hesitate to try for a different opening. I can tell you from experience that even as someone who was recruited, I didn't get hired for the first position I applied for.
Hope this helps, let me know if you have any more questions.
Rackspace has a Racker Vet group internally, so there's lots of support internally for veterans :)
If you have specific questions, feel free to ask me. If you want to see the job postings, you can find them here: http://www.rackspace.com/talent/
If there's a specific REQ# you are interested in, PM me and let me know more about you, and I could send through a recommendation.
I'm just an outsider observing and come back from time to time to this subreddit to see what is going on.
However to better understand what happened and to learn lessons that I can apply to my own career, I read the following books by the following ex-Rackers (I'm not promoting these books and get no compensation):
Billon or Bust: Growing a Tech Company in Texas
The Rack We Built: The Good, the Bad, and the Ugly of Creating Company Culture
Basically, this is what I took away from reading these two books:
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Here's an article about it: http://www.rackspace.com/knowledge_center/article/disabling-tcp-offloading-in-windows-server-2012 I'd leave it disabled tbh. Haven't seen that happen before where you couldn't load MS sites.