How to create diagrams

[Goldy]

What is the best way to create network topologys and diagrams like this?

Preferably freeware or a Microsoft Add In would be nice.

 

[chroniclard]

Tons online for free, google.

Though I use Visio the handful of times I have had to do diagrams.

 

[AHarvey]

check out realtimeboard, that has hundreds of uses like this

 

[Goldy]

Thanks guys. I found Draw.io which is exactly what i was after.

 

[Willir]

Microsoft Visio