Solved dhcp6c losing lease

[mariourk]

Hi,

After finally getting a proper ipv6 gateway running, I seem to have a problem with dhcp6c(8)

Everything runs smooth for several hours. And that I notice my internet connection is getting very unresponsive. After some inspection, I see my IPV6-addresses are gone. This of course results in time-outs, where my devices first try IPV6 and than fall back to IPV4, after a time-out.

Checking my FreeBSD server, it seems that rtadvd(8) is running fine. But msk0 doesn't have an IPV6 address any more. This suggests something is wrong with dhcp6c. And that of course also means that rtadvd(8) doesn't know what to broadcast any more.

I only have no idea what's going wrong here. Or where to get started. The logs give me nothing.

 

[mariourk]

The problem turned out to be a firewall problem. DHCP6c is listening to UDP-port 546. And that port was blocked, preventing DHCP6c to receive any reply to the requests it was broadcasting.

Oh, and the replies were adressed to the link-local address.

So, accept incoming traffic on UDP-port 546, for the link-local, and you should be fine.