I would suggest getting your Network+ first, but you don't HAVE too. All CompTIA certs are entry level, and really broad. The only reason I could see to take the Server+ first is because there is probably overlap in the material from A+.
Make sure before taking the Security+ that you study a lot. That is probably their hardest cert. You also are going to want to get the CISSP
certification, but for this one you will need a minimum of 5 years professional experience.