Problem Verizon Fios does not provide native dual-stack connectivity. To enable my connection for IPv6, I signed up for Hurricane Electric's Tunnelbroker service. To make a long story short, whenever the IPv4 IP on my Fios connection cycled to a new address, I had to manually update my new IPv4 IP in a few places (Tunnel Broker website, /etc/hostname.gif0) and run a few commands.
Solution Wrap ifstated with ping and a small shell script to automatically restart my IPv6 tunnel on the new IPv4 IP.
Now that I'm handing out IPv6 addresses to various VLANs on my network, I needed a way to see what percentage of my traffic was actually using IPv6. Enter pf, pflow, and ntop. pf is used by my router/firewall to process packets, and mark them for pflow processing. pflow is a psuedo device on the router/fw which exports pflow accounting data to a remote collector. ntop (and nprobe) is a collector and visualization application for digging into packet statistics.
I remember using he.net year ago for their IPv6 tunnels years ago, and have painful memories of configuring it, both on the router and to share to the subnets on my home LAN. Not this time. Years ago, I had Comcast Business Internet service, which along with providing a static IPv4 address, provided IPv6 connectivity. Not only just a single /128, but a whole /56 if you asked for it. After spending days/weeks configuring both dhcp client and servers for prefix delegation, and slaac/rtadvd to hand out addresses to my various LAN segments, I was in business.