All asked and answered dozens of times...
Go here:
http://archicadstuff.blogspot.com/
and search for "static ip"
or "vpn"
(Searching with the built-in forum search will not work with 3 letter or shorter terms, such as vpn or ip.)
No, you do not have to have a static IP. Yes, VPN can be a good solution for a number of reasons.
See also the various Wiki articles here:
http://www.archicadwiki.com/Teamwork
One of the forum moderators
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