Cisco DHCP Relay Agent to Windows DHCP server

Hello,

Just a quick query about Windows DHCP servers,

Are all DHCP relay agents compatible with all DHCP servers?

I heard somewhere that Cisco DHCP relay agents only work with Cisco DHCP servers ... Is this correct? Because I was hoping to use a Cisco router (Don't have it yet) to use it as a DHCP relay agent to a Windows DHCP Server

Thanks,

Chris :D