~S~ Nick and Arjen. Thanks for your help. So far everything is back to "normal" - regarding .Net versions etc. - I´m able to load Dynamic-DNS and run it again. IIt seems that I´m also able to connect to any server but Crash´s. Tested a couple 4.11 severs on Hyperlobby yesterday and it works. So does the mds-server, Friars, Painless and others. When pinging Crash´s server with tracert it stops somewhere before reaching Crash IP-adress. Also, nobody that tried, was able to connect to my server .
*#%&*>!% software buggers .