Looking 4 software to sync. between NT4

I am looking for a software to sync. 2 specific folders between NT4 servers.

2 NT4 servers located in different citys are connected through VPN, so the protocal this software uses can go through either internet or just within our internal network.

It must be smart enough to sync. deletion and addition instead of “just copy the files from server A to server B”.

This is for some critical database so is extremely important not to have mistake such as missing / redundant file. Assuming the connection is good, there are no file running / being opened, when this software does the job, there should be no error at all.

Whoever provides infomation and link of the software u suggest, I’ll review it very carefully.

After I decidethis is what I am looking for, I’ll release the points to you.