From: http://www.unix.com/ip-networking/71388-ipv6-udp-server-not-accepting-packets-global-address.html

Hi All,

I am running a IPv6 UDP server, which is bound to in6addr_any. When I send a packet from a client to the link-local address of any interface on the linux box, the server accepts the packets. But when I send the packets to the global address the server doesnt pick the packets.
On snooping I can see that the packets are reaching the interface.

I have tried with following global address 3ffe:x:x::x and 2001:db8:x:x:: addresses assigned to interface.

I checked the statistics and the Recv-Q seems to increment.

[root@pc4 root]# netstat -a -udp
Active Internet connections (servers and established)
Proto Recv-Q Send-Q Local Address Foreign Address State
udp 0 0 *:1024 *:*
udp 0 0 *:1025 *:*
udp 0 0 *:799 *:*
udp 0 0 *:800 *:*
udp 0 0 *:3503 *:*
udp 0 0 *:sunrpc *:*
udp 0 0 *:631 *:*
udp 0 0 40.40.40.1:ntp *:*
udp 0 0 30.30.30.2:ntp *:*
udp 0 0 10.11.4.40:ntp *:*
udp 0 0 94.94.94.94:ntp *:*
udp 0 0 ANVL:ntp *:*
udp 0 0 *:ntp *:*
udp 0 0 *:1023 *:*
udp 5196 0 *646 *:*

Please help.

Regards,
Murali