IPv6 Adventures

I’ve been getting a renewed interest in IPv6 lately. libreCMC default features include…

  • IPv6 stack
  • A WAN6 interface
  • IPv6 router functionality
  • DHCPv6 functionality

Unfortunately it seems that my ISP has not rolled out IPv6 support for residential customers, so I don’t have direct access to the IPv6 Internet. But of course I get IPv6 link local addresses generated automatically. And libreCMC by default advertises a router ULA prefix, meaning that my hosts automatically generate ULAs. ULA stands for Unique Local Addresses, which is basically the IPv6 equivalent of IPv4 private addresses. I can ping the libreCMC router from my host over IPv6:

christopher@nightshade:~$ ip neigh
<snip>
fd58:c37c:549c::1 dev eth0 lladdr e4:95:6e:4e:f0:a0 router STALE

# "one ping only"
christopher@nightshade:~$ ping -c 1 fd58:c37c:549c::1
PING fd58:c37c:549c::1(fd58:c37c:549c::1) 56 data bytes
64 bytes from fd58:c37c:549c::1: icmp_seq=1 ttl=64 time=0.471 ms

--- fd58:c37c:549c::1 ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 0.471/0.471/0.471/0.000 ms

I am able to view also the libreCMC Web page using the router’s ULA:

Screenshot from 2018-03-01 21-14-19.png

It seems that most Web browsers don’t support viewing a Web page by it’s link local address, for some reason. But, ssh has no trouble with them, so long as you specify the interface:

christopher@nightshade:~$ ssh root@fe80::e695:6eff:fe4e:f0a0%eth0
<snip>
root@libreCMC:~#

I’d like to connect to the IPv6 Internet but was having trouble figuring out the best transition option available to me. I can set the protocol for the WAN6 interface to 6in4 protocol, which I’d like to try, but I need to build and install the 6in4 package first.

It seems that my previous builds do not include busybox’s “ip neigh” program, for discovering other IPv6 hosts on the link. I’m planning to enable that in all future builds.

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