I got IPv6 working with my home router, DD-WRT, and Comcast’s 6to4 service.
\n[6to4](http:\/\/en.wikipedia.org\/wiki\/6to4) works by setting up a tunnel for IPv6 over IPv4. It uses the anycast address 192.88.99.1 as the tunnel endpoint. The IPv6 address is constructed from the host’s IPv4 address with 2002: prefix. 6to4 only works for hosts with public IP address which is why it has to be run on the router. [Comcast has 6to4 proxies](http:\/\/www.comcast6.net\/6to4-config.php). [Comcast was testing 6RD](http:\/\/www.comcast6.net\/6rd-config.php) which is similar but the prefix and proxy address are configured.<\/p>\n
First, I had to flash [DD-WRT to my WRT400N](http:\/\/www.dd-wrt.com\/wiki\/index.php\/Linksys_WRT400N). Second, I had to [enable IPv6](http:\/\/www.dd-wrt.com\/wiki\/index.php\/IPv6). The [6to4 config for 2.6 kernels](http:\/\/www.dd-wrt.com\/wiki\/index.php\/IPv6#6to4_on_k2.6_builds) requires a radvd config and startup script to be entered. Also, the scripts had to be changed for the WRT400N since they don’t have vlan2 device but eth1 worked.<\/p>\n
radvd config:<\/p>\n
interface br0 {
\n MinRtrAdvInterval 3;
\n MaxRtrAdvInterval 10;
\n AdvLinkMTU 1480;
\n AdvSendAdvert on;
\n prefix 0:0:0:1::\/64 {
\n AdvOnLink on;
\n AdvAutonomous on;
\n AdvValidLifetime 86400;
\n AdvPreferredLifetime 86400;
\n Base6to4Interface eth1;
\n };
\n }; <\/p>\n
Startup script:<\/p>\n
insmod \/lib\/modules\/`uname -r`\/kernel\/net\/ipv6\/sit.ko
\n sleep 5
\n radvd -C \/tmp\/radvd.conf start
\n sleep 5
\n WANIP=$(ip -4 addr show dev eth1 | grep ‘inet ‘ | awk ‘{print $2}’ | cut -d\/ -f1)
\n if [ -n “$WANIP” ]
\n then
\n V6PREFIX=$(printf ‘2002:%02x%02x:%02x%02x’ $(echo $WANIP | tr . ‘ ‘))
\n ip tunnel add tun6to4 mode sit ttl 255 remote any local $WANIP
\n ip link set tun6to4 mtu 1480
\n ip link set tun6to4 up
\n ip addr add $V6PREFIX:0::1\/16 dev tun6to4
\n ip addr add $V6PREFIX:1::1\/64 dev br0
\n ip -6 route add 2000::\/3 via ::192.88.99.1 dev tun6to4
\n kill -HUP $(cat \/var\/run\/radvd.pid)
\n fi
\n sleep 10
\n radvd -C \/tmp\/radvd.conf start <\/p>\n","protected":false},"excerpt":{"rendered":"
I got IPv6 working with my home router, DD-WRT, and Comcast’s 6to4 service. [6to4](http:\/\/en.wikipedia.org\/wiki\/6to4) works by setting up a tunnel for IPv6 over IPv4. It uses the anycast address 192.88.99.1 as the tunnel endpoint. The IPv6 address is constructed from the host’s IPv4 address with 2002: prefix. 6to4 only works for hosts with public IP […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[84,85],"tags":[],"class_list":["post-399","post","type-post","status-publish","format-standard","hentry","category-ipv6","category-networking"],"_links":{"self":[{"href":"https:\/\/znark.com\/blog\/wp-json\/wp\/v2\/posts\/399","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/znark.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/znark.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/znark.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/znark.com\/blog\/wp-json\/wp\/v2\/comments?post=399"}],"version-history":[{"count":4,"href":"https:\/\/znark.com\/blog\/wp-json\/wp\/v2\/posts\/399\/revisions"}],"predecessor-version":[{"id":404,"href":"https:\/\/znark.com\/blog\/wp-json\/wp\/v2\/posts\/399\/revisions\/404"}],"wp:attachment":[{"href":"https:\/\/znark.com\/blog\/wp-json\/wp\/v2\/media?parent=399"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/znark.com\/blog\/wp-json\/wp\/v2\/categories?post=399"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/znark.com\/blog\/wp-json\/wp\/v2\/tags?post=399"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}