Information Security, ever is an evolving domain with fast variance or options, broader view, shall be classified into Network Security / Application Security. For being a Network Security professional, need knowledge on perimeter guarding products like, firewall, VPN, DMZ, IDS, IPS, etc.. Similar way, for Application security demands knowledge on application attacks, application firewall, database security, security patching, etc..
Irrespective of Network security or Application security, fundamental knowledge on PC hardware, as most network appliances are build with similar design, good knowledge on various operating systems like windows, Apple Macintosh, Linux & Unix is a must as most end devices operate on these platforms.
In my personal experience, i would suggest basic networking fundamentals & data routing & switching knowledge would be more helpful in regards to Network security as one has to understand the base technology of network as Security is service rendered over the base computer networking.
Hope my insights helps, wishing you all success for your dream career.