Hellos, I'm trying to connect two computers under different NAT's but my head is a mess of concepts. Just some background, one of them uses Ubuntu (64 bit) under fastweb.it (my home desktop), the other WinXP under alice.it, I think (it's my work computer). Port 3874 is certainly blocked at work, will ask for the administrator to unblock it tomorrow. But for on this end, the setup for the Ubuntu machine was incredibly simple and it's up and running! The hardest part was creating Sixxs account, actually. :) Thanks a lot Sixxs and Jeron for aiccu! The actual question is, why do I need a tunnel broker? Is it because the hardware/NAT routers along the way might be ipv4-only? Or aiccu, why do I need a special piece of software on my computer to be able to use ipv6? For example, ifconfig gives me an "inet 6 address": eth0 Link encap:Ethernet HWaddr 00:18:f3:52:f2:85 inet addr:1.123.33.138 Bcast:1.123.33.255 Mask:255.255.255.0 inet6 addr: fe80::218:f3ff:fe52:f285/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:44219 errors:0 dropped:0 overruns:0 frame:0 TX packets:37578 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:48313161 (48.3 MB) TX bytes:5506147 (5.5 MB) Interrupt:248 Base address:0x4000 Why can't I use it? Ok, after reading this Address scopes, I understand it means just an address on a local scope, but why do I need Sixxs to get a Global one? Shouldn't my ISP provide that? Any kind of clarification is much welcomed.