After apply for the job offer, I received an email in order to appoint a call for the telephonic intervew. The interviewer was very polite, but the call quality was realy bad, enough to be only able to understand 50% of it. The only solution suggested by the interviewer was that he could repeat again the sentences.
To add up to difficulty, some of the questions were to certain MS SQL, MySQL or Apache parameters that, if you only to that, shouldn't suppose an issue, but if you touch more things, like OpenStack, it can be really challenging to know off the top of one's head.
This of course can be easy to solve: Ask them what techs they are interested in before the interview and check the config files before.
I've been a Linux Administrator for +8 years, yet I wasn't able to answer trivial questions becuase they were too specific, I was too nervous and really understood half of the question.
Also, at some of them I asked the interviewer if he was referring to a certain technology yet he took my question as my answer.
This might be the worst interview I have ever had.