There are two rounds, the first is Phone interview, and the second is on-site Interview. If you have enough security and network fundamental knowledge, you are fine. I did well during the Interview. And I had a good discussion with the Technical hiring manager and the team. And after the on-site interview, they asked for 5 references from my professional manager and friends. But after I finished everything, they did not give me the offer, because they do not want to provide sponsorship. The HR told me that they wanted to open the job for several weeks to see if there is proficient US-citizen candidates.