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: Since today 07:30 CET, my tunnel T13867 doesn't work anymore without any changes on my side (I haven't been on site at that time). "aiccu test" gives me the following information: Tunnel Information for T13867: POP Id : deham01 IPv6 Local : 2001:6f8:900:aa7::2/64 IPv6 Remote : 2001:6f8:900:aa7::1/64 Tunnel Type : ayiya Adminstate : enabled Userstate : enabled A ping to the remote tunnel end: PING 2001:6f8:900:aa7::1(2001:6f8:900:aa7::1) 56 data bytes --- 2001:6f8:900:aa7::1 ping statistics --- 10 packets transmitted, 0 received, 100% packet loss, time 9020ms A ping to the remote tunnel end via IPv4 is successful. AICCU writes the following into my logs: Feb 18 11:31:33 prisma aiccu: sock_getline() : "200 SixXS TIC Service on noc.sixxs.net ready (http://www.sixxs.net)" Feb 18 11:31:33 prisma aiccu: sock_printf() : "client TIC/draft-00 AICCU/2007.01.15-console-linux Linux/2.6.18-6-k7" Feb 18 11:31:33 prisma aiccu: sock_getline() : "200 Client Identity accepted" Feb 18 11:31:33 prisma aiccu: sock_printf() : "get unixtime" Feb 18 11:31:33 prisma aiccu: sock_getline() : "200 1234953093" Feb 18 11:31:33 prisma aiccu: sock_printf() : "starttls" Feb 18 11:31:33 prisma aiccu: sock_getline() : "400 This service is not SSL enabled (yet)" Feb 18 11:31:33 prisma aiccu: TIC Server does not support TLS but TLS is not required, continuing Feb 18 11:31:33 prisma aiccu: sock_printf() : "username DWQ1-SIXXS" Feb 18 11:31:34 prisma aiccu: sock_getline() : "200 Choose your authentication challenge please" Feb 18 11:31:34 prisma aiccu: sock_printf() : "challenge md5" Feb 18 11:31:34 prisma aiccu: sock_getline() : "200 ***" Feb 18 11:31:34 prisma aiccu: sock_printf() : "authenticate md5 ***" Feb 18 11:31:34 prisma aiccu: sock_getline() : "200 Succesfully logged in using md5 as DWQ1-SIXXS (Daniel Weber) from 2001:7b8:3:4f:202:b3ff:fe46:bec" Feb 18 11:31:34 prisma aiccu: sock_printf() : "tunnel show T13867" Feb 18 11:31:34 prisma aiccu: sock_getline() : "201 Showing tunnel information for T13867" Feb 18 11:31:34 prisma aiccu: sock_getline() : "TunnelId: T13867" Feb 18 11:31:34 prisma aiccu: sock_getline() : "Type: ayiya" Feb 18 11:31:34 prisma aiccu: sock_getline() : "IPv6 Endpoint: 2001:6f8:900:aa7::2" Feb 18 11:31:34 prisma aiccu: sock_getline() : "IPv6 POP: 2001:6f8:900:aa7::1" Feb 18 11:31:34 prisma aiccu: sock_getline() : "IPv6 PrefixLength: 64" Feb 18 11:31:34 prisma aiccu: sock_getline() : "Tunnel MTU: 1280" Feb 18 11:31:34 prisma aiccu: sock_getline() : "Tunnel Name: My First Tunnel" Feb 18 11:31:34 prisma aiccu: sock_getline() : "POP Id: deham01" Feb 18 11:31:34 prisma aiccu: sock_getline() : "IPv4 Endpoint: ayiya" Feb 18 11:31:34 prisma aiccu: sock_getline() : "IPv4 POP: 212.224.0.188" Feb 18 11:31:34 prisma aiccu: sock_getline() : "UserState: enabled" Feb 18 11:31:34 prisma aiccu: sock_getline() : "AdminState: enabled" Feb 18 11:31:34 prisma aiccu: sock_getline() : "Password: ***" Feb 18 11:31:34 prisma aiccu: sock_getline() : "Heartbeat_Interval: 60" Feb 18 11:31:34 prisma aiccu: sock_getline() : "202 Done" Feb 18 11:31:34 prisma aiccu: Succesfully retrieved tunnel information for T13867 Feb 18 11:31:34 prisma aiccu: sock_printf() : "QUIT Deer Stop" Feb 18 11:31:34 prisma aiccu: AICCU running as PID 2405 Feb 18 11:31:34 prisma aiccu: [AYIYA-start] : Anything in Anything (draft-02) Feb 18 11:31:34 prisma aiccu: [AYIYA-tun->tundev] : (Socket to TUN) started (Note: Password and Hashes removed.) The tunnel endpoint is a Debian Etch (Linux prisma 2.6.18-6-k7 #1 SMP Sat Dec 27 10:04:42 UTC 2008 i686 GNU/Linux) behind a NAT-box with IPv4 connectivity via a private ADSL. My setup has been working fine for months.