have (2) linksys (NEW) RV042 routers with VPN. All data works fine (routers don't limit traffic via VPN. I noticed a couple of posts that had no problems however I continue to have the same issue with a 5610SW that always says "Extension in use # to register". The telephone will refuse to do anything else and the monitor log shows "cause=18 no user responding . . . "ALl of my data traffic works fine with no issues. Softphone works great as well. The hardphone continues to be an issue.