Worked fine on Debian, but after OS reload it does not

[masterwane]

I have two Linux Debian machines in my house. They were both working fine with HE IPv6 tunnel. I backed up /etc/network/interfaces on one of them and I reinstalled the OS. I am sure the settings in /etc/network/interfaces are correct but I do not have IPv6 access. I can only think that there is some other setting in the OS? please give me your thoughts as what the problem could be.

[cholzhauer]

Can you post what you're trying to use?  More details are helpful