Dear maintainer, I am struggling with IPv6 over PPP on Linux. The situation is that I have a 3G modem, when I plug it in to the USB on my Debian box, everything works as expected, I have IPv6 address from the provider, and I am happy. But how? This is the relevant log: Jun 14 12:37:03 mercury pppd[3282]: Serial connection established. Jun 14 12:37:03 mercury pppd[3282]: using channel 2 Jun 14 12:37:03 mercury pppd[3282]: Using interface ppp0 Jun 14 12:37:03 mercury pppd[3282]: Connect: ppp0 <--> /dev/ttyUSB3 Jun 14 12:37:04 mercury pppd[3282]: sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0xa2034878> <pcomp> <accomp>] Jun 14 12:37:04 mercury pppd[3282]: rcvd [LCP ConfReq id=0x3 <asyncmap 0x0> <auth chap MD5> <magic 0xc700eac2> <pcomp> <accomp>] Jun 14 12:37:04 mercury pppd[3282]: No auth is possible Jun 14 12:37:04 mercury pppd[3282]: sent [LCP ConfRej id=0x3 <auth chap MD5>] Jun 14 12:37:04 mercury pppd[3282]: rcvd [LCP ConfAck id=0x1 <asyncmap 0x0> <magic 0xa2034878> <pcomp> <accomp>] Jun 14 12:37:04 mercury pppd[3282]: rcvd [LCP ConfReq id=0x4 <asyncmap 0x0> <magic 0xc700eac2> <pcomp> <accomp>] Jun 14 12:37:04 mercury pppd[3282]: sent [LCP ConfAck id=0x4 <asyncmap 0x0> <magic 0xc700eac2> <pcomp> <accomp>] Jun 14 12:37:04 mercury pppd[3282]: sent [LCP EchoReq id=0x0 magic=0xa2034878] Jun 14 12:37:04 mercury pppd[3282]: sent [IPCP ConfReq id=0x1 <addr 0.0.0.0> <ms-dns1 0.0.0.0> <ms-dns2 0.0.0.0>] Jun 14 12:37:04 mercury pppd[3282]: sent [IPV6CP ConfReq id=0x1 <addr fe80::3d17:0512:2b44:658b>] Jun 14 12:37:04 mercury pppd[3282]: rcvd [LCP DiscReq id=0x5 magic=0xc700eac2] Jun 14 12:37:04 mercury pppd[3282]: rcvd [LCP EchoRep id=0x0 magic=0xc700eac2 a2 03 48 78] Jun 14 12:37:05 mercury pppd[3282]: rcvd [IPV6CP ConfNak id=0x1 <addr fe80::330e:c05c:0d76:f234>] Jun 14 12:37:05 mercury pppd[3282]: sent [IPV6CP ConfReq id=0x2] Jun 14 12:37:06 mercury pppd[3282]: rcvd [IPV6CP ConfNak id=0x1 <addr fe80::fc17:3ad2:5917:3248>] Jun 14 12:37:07 mercury pppd[3282]: sent [IPCP ConfReq id=0x1 <addr 0.0.0.0> <ms-dns1 0.0.0.0> <ms-dns2 0.0.0.0>] Jun 14 12:37:08 mercury pppd[3282]: rcvd [IPV6CP ConfReq id=0x0 <addr fe80::2c26:30b4:e65c:5b4a>] Jun 14 12:37:08 mercury pppd[3282]: sent [IPV6CP ConfAck id=0x0 <addr fe80::2c26:30b4:e65c:5b4a>] Jun 14 12:37:08 mercury pppd[3282]: rcvd [IPV6CP ConfNak id=0x2 <addr fe80::303e:582f:ea95:aa10>] Jun 14 12:37:08 mercury pppd[3282]: sent [IPV6CP ConfReq id=0x3 <addr fe80::303e:582f:ea95:aa10>] Jun 14 12:37:08 mercury pppd[3282]: rcvd [IPV6CP ConfAck id=0x3 <addr fe80::303e:582f:ea95:aa10>] Jun 14 12:37:08 mercury pppd[3282]: local LL address fe80::303e:582f:ea95:aa10 Jun 14 12:37:08 mercury pppd[3282]: remote LL address fe80::2c26:30b4:e65c:5b4a Jun 14 12:37:08 mercury pppd[3282]: Script /etc/ppp/ipv6-up started (pid 3298) Jun 14 12:37:08 mercury pppd[3282]: Script /etc/ppp/ipv6-up finished (pid 3298), status = 0x0 After seeing the interface, I have the global scope address like this: lev@mercury:~$ /sbin/ifconfig ppp0 ppp0: flags=4305<UP,POINTOPOINT,RUNNING,NOARP,MULTICAST> mtu 1500 inet6 2a00:1110:135:4594:303e:582f:ea95:aa10 prefixlen 64 scopeid 0x0<global> inet6 fe80::303e:582f:ea95:aa10 prefixlen 10 scopeid 0x20<link> ppp txqueuelen 3 (Point-to-Point Protocol) RX packets 73 bytes 14234 (13.9 KiB) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 95 bytes 10012 (9.7 KiB) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0 Please note that in the logs, I can't see that global scope address, and I don't know how the IPv6CP assigns this address to the interface. How is this done? And when I plug the same modem to an OpenWRT box, I don't get the global scope address, only the link-local address. Is this some PPP specific problem, or there might be some IPv6 autoconfiguration magic happening in the background? I don't think so, because that address corresponds to a statically allocated address of the provider. lev@mercury:~$ host 2a00:1110:135:4594:303e:582f:ea95:aa10 0.1.a.a.5.9.a.e.f.2.8.5.e.3.0.3.4.9.5.4.5.3.1.0.0.1.1.1.0.0.a.2.ip6.arpa domain name pointer 2A00111001354594303E582FEA95AA10.mobile.pool.telekom.hu. Could you help me out what is going on here, and why can't I get a global scope address on the OpenWRT? I'm sure it is an OpenWRT issue, but need help tracing it. Thanks, Levente