I recently setup another WAN connection by assigning one of my existing LAN ports on my Linksys WRT3200ACM onto a new VLAN (eth0.3), I have both working IPv4 and IPv6 connectivity on the eth0.3 interface confirmed through ping and traceroute, however I have noticed some IPv6 domains/literal IPv6 addresses return the following error:
ping6: sendto: Permission denied
The same with traceroute and even cURL (error 7), however it's not happening on all IPv6 DNS/literal tests.
Example for ipv6.google.com, working fine:
root@linksys-wrt3200acm:~# ping6 -I eth0.3 ipv6.google.com PING ipv6.google.com (2a00:1450:4009:816::200e): 56 data bytes 64 bytes from 2a00:1450:4009:816::200e: seq=0 ttl=50 time=123.716 ms 64 bytes from 2a00:1450:4009:816::200e: seq=1 ttl=50 time=28.521 ms 64 bytes from 2a00:1450:4009:816::200e: seq=2 ttl=50 time=24.645 ms 64 bytes from 2a00:1450:4009:816::200e: seq=3 ttl=50 time=26.934 ms 64 bytes from 2a00:1450:4009:816::200e: seq=4 ttl=50 time=25.919 ms
Yet if I then test with one the Google IPv6 DNS addresses:
root@linksys-wrt3200acm:~# ping6 -I eth0.3 2001:4860:4860::8888 PING 2001:4860:4860::8888 (2001:4860:4860::8888): 56 data bytes ping: sendto: Permission denied
I first thought firewall, but I'm not sure because I figured all IPv6 traffic wouldn't work at all, yet it does, just I found this example and a few others. It was brought to my attention as mwan3 was detecting the interface as down, which led me to discover ping test were failing as the interface ping test was using Google IPv6 DNS and OpenDNS, both which return the above error when pinging.
Can anyone shed some light on the the ping error is indicating?