Hello. Thank you for your kind reply. > Mr. SekiyaHexadecimal _expression_ of IPv4 addresses which are assigned to physical devices are used for forming IPv6 link-local addresses for sit devices. Are both of eth0 and eth1 interface alive and do both of them have connectivity ?I'm sorry for lack of information. Yes. eth{0,1} are alive and connectivity. Eth0 is assigned gloval IPv4 IP, connected to outer network and eth1 is assigned private IPv4 IP and connected to private network. (My linux box is used for IP Masquerade.) I agree that sit1 decice has two address (in this case, "fe80::9641:2913/64" and "fe80::c0a8:1/64"). +-----+ eth1 +-------+ eth0 +---------+ | Hub |-------------| linux |-----....---| Solaris | | | | box | | (*) | +-----+ | | | | | +-------+ +---------+ . private <-|-> outer (global) . network | network . (*): Solaris accepts only packets which source address is "fe80::9641:2913") I try to connect to Solaris8 machine using 6to4. Solaris8 supports 6to4 tunneling however it accepts only addresses that is configured. In my Solaris8, I append only "fe80::9641:2913" to tunneling list. In first case of the my previous mail, ---------------- bash-2.05$ ping6 ff02::1%sit1 PING ff02::1%sit1(ff02::1%sit1) from fe80::c0a8:1%sit1 : 56 data bytes 64 bytes from ::1: icmp_seq=1 ttl=64 time=0.307 ms ---------------- Linux send ICMP message to Solaris machine using the packet whose source address is "fe80::c0a8:1", therefore Solaris machine doesn't reply packet. Solaris accepts only the packets whose source address is "fe80::9641:2913". I'd like to - know about how to decide the source address of sit1, and - change source address of sit1. (in this case, fe80::c0a8:1 -> fe80::9641:2913) Kind regards. -- ========================================================== Japan Advanced Institute of Science and Technology ------- Name:Tomofumi Hayashi E-Mail Address: thayashi@xxxxxxxxxxx URL:http://www.jaist.ac.jp/~thayashi/ ==========================================================