How to have a file or string available to multiple computers and be able to changed and rewritten in C#? : <br>
I have a bit of an issue/question. <br>
I am trying to write a program that generates a specific serial number but it will be able to be accessed by multiple computers in different locations. <br>
The serial number will look something like this:<br> 

(2 letters)AA(month)02(year)16(four numbers)0000<br>
Full thing: AA02160000<br>

The last 4 digits will increment by one every time the user clicks a button. 
I need to be able to get that serial number from multiple computers in different locations not on the same network and edit it and rewrite it. I can't have any sort of overlap being a serial number and unique to a specific item. I also can't use a guid for the number otherwise it would be much easier.

What is the best way to do this in C#?

I have considered making a server for it but I was running into problems when trying to create directories to pull the number from because of the drive letter. 

Can I access a website that is hosted on a computer in one location and have it grab that serial number and increment it and then place the new value on the website? 

Quite honestly I'm spinning in circles with a million ways to do and not knowing the proper/best way to do it. A bit of help here would be much appreciated. 
