Are Quest Rewards Server sided?

I have been reading the forums a lot over the last few weeks, and I've seen that many people are trying to gain weapons/armors by using various creative methods. Unfortunately, all of these methods, such as editing shopkeepers, failed. So I was wondering if anyone tried to edit a hfs to change the quest reward given or if this is impossible due to the quest being server sided.

~Thanks

Also server sided, client has to force something to happen, you can't edit the server to give rewards, unfortunately.

I see, well thanks xD

Any idea as to what that force would be?