ipv6 forwarding issue

[krbvroc1]

I have been setting up ipv6 on my RT-N66U 374.33. I thought things were working the other day, but it is no longer.

While the router (via ssh) is able to ping6 an ipv6 site, no devices on the LAN are able to. After messing around for a few hours, I executed the following which fixed it.

echo 1 > /proc/sys/net/ipv6/conf/all/forwarding

So my question is, why is this not being set, and what software/routines during the bootup sequence control setting it?

I believe it should definitely be set to forward IPv6.
There is an nvram variable 'ipv6_fw_enable' that is set.

 

[krbvroc1]

So I *think* what has happened is that I have 'Enable Router Advertisement' disabled. That is because I want the flexibility of two possibilities:
1) I use firewall-start script to auto generate a /etc/radvd.conf using a script to replace the RRDNS with the ipv6 address of the router (nvram get ipv6_rtr_addr). And to replace the prefix (nvram get ipv6_prefix). That way dnsmasq is used to cache and handle ipv6 lookups (including local domain searches). So after generating that, I run radvd from the firewall-start.
2) In the future I will probably not use radvd since dnsmaq (especially version 2.67) can handle router advertisements via the enable-ra option.

Looking at the source code, I believe the 'start_lan' function in src/router/rc/lan.c is responsible for turning on ipv6 forwarding. It does not do so if radvd is disabled. Sounds like a bug to me. Using radvd is not really required for ipv6 forwarding.

 

[RMerlin]

So I *think* what has happened is that I have 'Enable Router Advertisement' disabled. That is because I want the flexibility of two possibilities:

Asus were indeed disabling IPv6 forwarding if radvd was disabled. They reverted this in the recent 374_339 release for the RT-AC68U.