My tunnel, #11107, which is a heartbeat tunnel configured to use the fihel01 PoP, owned by the MSL2-SIXXS account, stopped working today (7 Sept 2009), around 06:22 UTC, and there was no configuration change from my part at that time. Before this, the same tunnel has been running without hiccups for many months. When running "aiccu test", the first test that failed was ###### [6/8] Ping the IPv6 Remote/PoP Inner Tunnel Endpoint (2001:14b8:100:1c1::1). According to the tunnel status page, my heartbeat IPv4 address is 0.0.0.0, so apparently the PoP hasn't received any heartbeat in a while. To debug the problem, I tested sending UDP packets to port 3740 to another host (on another ISP), which was able to receive the packets well, thus this shouldn't be a firewall problem at my end. My aiccu is version AICCU 2007.01.15-console-linux, which is the latest in debian stable. Here's the aiccu verbose output: sock_getline() : "200 SixXS TIC Service on noc.sixxs.net ready (http://www.sixxs.net)" sock_printf() : "client TIC/draft-00 AICCU/2007.01.15-console-linux Linux/2.6.26-2-686" sock_getline() : "200 Client Identity accepted" sock_printf() : "get unixtime" sock_getline() : "200 1252335851" sock_printf() : "starttls" sock_getline() : "400 This service is not SSL enabled (yet)" TIC Server does not support TLS but TLS is not required, continuing sock_printf() : "username MSL2-SIXXS" sock_getline() : "200 Choose your authentication challenge please" sock_printf() : "challenge md5" sock_getline() : "200 06c4216a47eb1d67eb991931b18d315f" sock_printf() : "authenticate md5 2194609fcc177bd6aeecc150c47382e1" sock_getline() : "200 Succesfully logged in using md5 as MSL2-SIXXS (Martin Storsjo) from 2001:7b8:3:4f:202:b3ff:fe46:bec" sock_printf() : "tunnel show T11107" sock_getline() : "201 Showing tunnel information for T11107" sock_getline() : "TunnelId: T11107" sock_getline() : "Type: 6in4-heartbeat" sock_getline() : "IPv6 Endpoint: 2001:14b8:100:1c1::2" sock_getline() : "IPv6 POP: 2001:14b8:100:1c1::1" sock_getline() : "IPv6 PrefixLength: 64" sock_getline() : "Tunnel MTU: 1280" sock_getline() : "Tunnel Name: My First Tunnel" sock_getline() : "POP Id: fihel01" sock_getline() : "IPv4 Endpoint: heartbeat" sock_getline() : "IPv4 POP: 62.78.96.38" sock_getline() : "UserState: enabled" sock_getline() : "AdminState: enabled" sock_getline() : "Password: <removed>" sock_getline() : "Heartbeat_Interval: 60" sock_getline() : "202 Done" Succesfully retrieved tunnel information for T11107 sock_printf() : "QUIT Something I can never have" Tunnel Information for T11107: POP Id : fihel01 IPv6 Local : 2001:14b8:100:1c1::2/64 IPv6 Remote : 2001:14b8:100:1c1::1/64 Tunnel Type : 6in4-heartbeat Adminstate : enabled Userstate : enabled heartbeat_socket() - IPv4 : 88.193.196.75 [HB] HEARTBEAT TUNNEL 2001:14b8:100:1c1::2 sender 1252335851 474dbc125bacaf494c758ceb558c8e19 [HB] HEARTBEAT TUNNEL 2001:14b8:100:1c1::2 sender 1252335851 474dbc125bacaf494c758ceb558c8e19 Traceroute to the PoP: traceroute to 62.78.96.38 (62.78.96.38), 30 hops max, 40 byte packets 1 dsl-tkubrasgw1-fe00fa00-1.dhcp.inet.fi (84.250.0.1) 7.206 ms 7.417 ms 7.664 ms 2 141.208.23.13 (141.208.23.13) 6.821 ms 7.778 ms 7.971 ms 3 hkicore1-e-1-3-0.datanet.tele.fi (141.208.8.166) 10.555 ms 11.333 ms 11.731 ms 4 hkiasbr1-s0-0-0.datanet.tele.fi (141.208.8.10) 11.831 ms 12.279 ms 12.739 ms 5 dna.ficix1-ge.ficix.fi (193.110.226.20) 13.416 ms 13.886 ms 14.575 ms 6 van1-er6.dnaip.fi (62.78.108.111) 15.289 ms 9.909 ms 8.748 ms 7 fihel01.sixxs.net (62.78.96.38) 9.819 ms 10.187 ms 10.602 ms