I have read and followed the "Reporting Problems" section on the Contact page and am providing the following details for this report based on the list of items stated there: Not sure if it's a SIXXS problem but I am experiencing connectivity problems lately. Whenever I try to ping any IPv6 address, the first ping goes through, and subsequent requests fail on all Windows boxes. Seems that Windows removes the default route after the first ping response arrives, so subsequent packets fail. Restarting RADVD on the router brings back the missing route but any communication causes an error. Pinging ipv6.l.google.com [2001:4860:0:1001::68] from 2001:15c0:6654::1 with 32 bytes of data: Reply from 2001:4860:0:1001::68: time=92ms PING: transmit failed, error code 1214. PING: transmit failed, error code 1214. PING: transmit failed, error code 1214. The same request from Linux boxes seem to go through any time: root@OpenWrt:~# ping6 ipv6.google.com PING ipv6.l.google.com (2001:4860:0:1001::68): 56 data bytes 64 bytes from 2001:4860:0:1001::68: icmp6_seq=0 ttl=56 time=95.1 ms 64 bytes from 2001:4860:0:1001::68: icmp6_seq=1 ttl=56 time=89.9 ms 64 bytes from 2001:4860:0:1001::68: icmp6_seq=2 ttl=56 time=87.0 ms No config changes have been made to my infrastructure. Are you aware of any Windows updates that might have impacted IPv6 connectivity? I am using AICCU on a ASUS WL500gP router configured for AYIYA