Got an /29 network here. My network config with /29 network is: # The loopback interface auto lo iface lo inet loopback # The first network card - this entry was created during the Debian installation # (network, broadcast and gateway are optional) auto eth0 iface eth0 inet static address 10.0.0.1 netmask 255.255.255.0 network 10.0.0.0 broadcast 10.0.0.255 auto eth1 iface eth1 inet static address 145.99.196.186 netmask 255.255.255.248 network 145.99.196.184 broadcast 145.99.196.191 gateway 145.99.196.185 auto sixxs iface sixxs inet6 v4tunnel address 2001:960:2:84::2 netmask 64 endpoint 213.204.193.2 ttl 64 up ip link set mtu 1280 dev sixxs up ip route add 2000::/3 via 2001:960:2:84::1 dev sixxs auto eth1:0 iface eth1:0 inet static address 145.99.196.187 netmask 255.255.255.248 network 145.99.196.184 broadcast 145.99.196.191 gateway 145.99.196.185 auto eth1:1 iface eth1:1 inet static address 145.99.196.188 netmask 255.255.255.248 network 145.99.196.184 broadcast 145.99.196.191 gateway 145.99.196.185 auto eth1:2 iface eth1:2 inet static address 145.99.196.190 netmask 255.255.255.248 network 145.99.196.184 broadcast 145.99.196.191 gateway 145.99.196.185 When i use the above config i cant use my ipv6 tunnel. When i remove the configuration for eth1:0, eth1:1 and eth1:2 it does work. What am i doing wrong here? Thanks in advance