I restarted the computer and since then the ipv6 tunnel doesn't work. I'm running openbsd 3.7 I have a problem with the route, i think: (illegal prefixlen) Internet6: Destination Gateway Flags Refs Use Mtu Interface ::/104 localhost UGRS 0 0 - lo0 ::/96 localhost UGRS 0 0 - lo0 route: illegal prefixlen ::/4 gw-115.bru-01.be.s UGS 0 10 - gif0 localhost localhost UH 0 6 33224 lo0 ::127.0.0.0/104 localhost UGRS 0 0 - lo0 ::224.0.0.0/100 localhost UGRS 0 0 - lo0 ::255.0.0.0/104 localhost UGRS 0 0 - lo0 ::ffff:0.0.0.0/96 localhost UGRS 0 0 - lo0 gw-115.bru-01.be.s cl-115.bru-01.be.s UH 0 25 - gif0 cl-115.bru-01.be.s link#6 UHL 0 14 - lo0 2002::/24 localhost UGRS 0 0 - lo0 2002:7f00::/24 localhost UGRS 0 0 - lo0 2002:e000::/20 localhost UGRS 0 0 - lo0 2002:ff00::/24 localhost UGRS 0 0 - lo0 fe80::/10 localhost UGRS 0 0 - lo0 fe80::%sis0/64 link#1 UC 0 0 - sis0 fe80::240:33ff:fee 00:40:33:e3:5b:d1 UHL 0 0 - lo0 fe80::%rl0/64 link#2 UC 0 0 - rl0 fe80::240:f4ff:fe3 00:40:f4:31:12:96 UHL 0 0 - lo0 fe80::%lo0/64 fe80::1%lo0 U 0 0 - lo0 fe80::1%lo0 link#5 UHL 0 0 - lo0 fe80::%gif0/64 link#6 UC 0 0 - gif0 fe80::240:33ff:fee link#6 UHL 0 0 - lo0 fec0::/10 localhost UGRS 0 0 - lo0 ff01::/32 localhost UC 0 0 - lo0 ff02::%sis0/32 link#1 UC 0 0 - sis0 ff02::%rl0/32 link#2 UC 0 0 - rl0 ff02::%lo0/32 localhost UC 0 0 - lo0 ff02::%gif0/32 link#6 UC 0 0 - gif0 ifconfig gif0 gives: gif0: flags=8051<UP,POINTOPOINT,RUNNING,MULTICAST> mtu 1280 physical address inet my_ip --> 212.100.184.146 inet6 fe80::240:33ff:fee3:5bd1%gif0 -> prefixlen 64 scopeid 0x6 inet6 2001:6f8:202:72::2 -> 2001:6f8:202:72::1 prefixlen 128 I runned then sixxs-aiccu autotest and the problem begins at the step 6/8 ###### [6/8] Ping the IPv6 Remote/POP Inner Tunnel Endpoint (2001:6f8:202:72::1) ### This confirms the reachability of the other side of the tunnel ### If it doesn't reply then check your interface and routing tables ### Don't forget to check your firewall of course ### If the previous test was succesful then this could be both ### a firewalling and a routing/interface problem PING6(56=40+8+8 bytes) 2001:6f8:202:72::2 --> 2001:6f8:202:72::1 --- 2001:6f8:202:72::1 ping6 statistics --- 3 packets transmitted, 0 packets received, 100.0% packet loss I also tried to disable the firewall but it doesn't change anything..