Dears, I want to know your suggestion about below points

1- Best free Linux distribution for enterprise ?
2- Best none free Linux distribution for enterprise ?


Thanks

There is no 'best' distribution for ANYTHING. You need to decided what hardware you're going to be running this on, and what environment you're comfortable in. Some people like Debian-based systems, some like Red Hat. ANY version of Linux can run pretty much any piece of a 'server' (web, mail, time, DNS, DHCP, etc.)

ANYTHING like this is totally subjective; one person might be best off with Oracle Linux, while that may be a poor choice for someone else. Figure out what you want to do and what the hardware is, and then look at the system requirements to pick a distro.