What is Microsoft ISA Server?

Firewall Sever and it's working as Router but if you need router MicroTik good than ISA I hope was helpful, vote if it is

ISA Server is Microsoft firewall, proxy, web cache and Internet gateway solution that run on Window Server. Microsoft renamed ISA Server after its product ISA Server2006 to Forefront TMG with some new features like content filtering, NIS and some other features with separate licenses.