I have been experiencing for a few months a strange problem with the IPv6 tunnel on my OpenWrt router.
My configuration is:
Linux 220.127.116.11 (MIPS)
The IPv4 connection (ADSL2) is at about 10Mbps (MegaBITpersecond)
I have made some test with a file (700MByte) hosted on a remote server (with low-latency and no bandwidth problem).
The router establishs the ipv6 tunnel to tunnelbroker with the "ip" utility and shares the tunnel with the internal network, about ten devices via wifi and lan.
If i download the file directly from the router, i get a speed of about 7-8Mbps, but if i download the file from any pc of the internal network, i get a very slow speed.. about 20Kbps (less then 1KB/s).
To debug it I removed any ip6tables rule (ACCEPT/ACCEPT/ACCEPT) and i found that there isn't any cpu/ram overload.
Obviously i have rebooted the router many times, with no result
Thanks in advance for any help
[EDIT] maybe a MTU problem? now the ADSLv4 is 1460, the internal network is 1500, the ipv6 tunnel is 1440