Its quite hard to find a decent place online for this as I've found there's almost nothing. If you are going to use the following:
Udemy or Sololearn, make sure the courses are up to date as a lot of them i've found is not.
The best one I can say is Pluralsight.com its premium but well worth it. It gives you access to cybersecurity and my other half I believe he's done all of his certified Cisco qualifications on there.
It's expensive but well worth it!