Router not getting an IPv6 prefix from ISP (init7)

AndrewZ · September 30, 2024, 8:31pm

You need to compare decoded DHCPv6 Solicit requests.

mk24 · September 30, 2024, 8:41pm

Yes, make sure the request is internally the same. Use the -vv option for tcpdump to do that.

billybob · October 3, 2024, 8:02pm

I've repeated the tcdump commands with -vv flag.
I start the tcpdump command in the shell of the openWRT router, and then restart the wan6 interface from the LuCI web interface to capture the traffic.

From the site that works:

ot@OpenWrt:~# tcpdump -vv -n -i eth0.2 portrange 546-547
tcpdump: listening on eth0.2, link-type EN10MB (Ethernet), snapshot length 262144 bytes
19:54:48.136796 IP6 (flowlabel 0x535ad, hlim 1, next-header UDP (17) payload length: 179) fe80::b2b9:8aff:fe73:5a5c.546 > ff02::1:2.547: [udp sum ok] dhcp6 release (xid=b302ef (elapsed-time 0) (option-request SIP-servers-domain SIP-servers-address DNS-server DNS-search-list SNTP-servers NTP-server AFTR-Name opt_67 opt_94 opt_95 opt_96) (client-ID hwaddr type 1 b0b98a735a5c) (server-ID hwaddr/time type 1 time 708449505 a209da24f4bf) (Client-FQDN) (IA_NA IAID:1 T1:0 T2:0 (IA_ADDR 2a02:168:2000:3c::b pltime:0 vltime:0)) (IA_PD IAID:1 T1:0 T2:0 (IA_PD-prefix 2a02:168:b998::/48 pltime:0 vltime:0)))
19:54:48.157411 IP6 (class 0xe0, hlim 255, next-header UDP (17) payload length: 223) fe80::200:f7ff:fef7:256.547 > fe80::b2b9:8aff:fe73:5a5c.546: [udp sum ok] dhcp6 reply (xid=b302ef (client-ID hwaddr type 1 b0b98a735a5c) (server-ID hwaddr/time type 1 time 708449505 a209da24f4bf) (IA_NA IAID:1 T1:0 T2:0 (status-code Success)) (status-code Success) (IA_PD IAID:1 T1:0 T2:0 (status-code Success)))
19:54:48.718926 IP6 (flowlabel 0x535ad, hlim 1, next-header UDP (17) payload length: 110) fe80::b2b9:8aff:fe73:5a5c.546 > ff02::1:2.547: [udp sum ok] dhcp6 solicit (xid=c04d67 (elapsed-time 0) (option-request SIP-servers-domain SIP-servers-address DNS-server DNS-search-list SNTP-servers NTP-server AFTR-Name opt_67 opt_94 opt_95 opt_96 opt_82) (client-ID hwaddr type 1 b0b98a735a5c) (reconfigure-accept) (Client-FQDN) (IA_NA IAID:1 T1:0 T2:0) (IA_PD IAID:1 T1:0 T2:0))
19:54:48.727214 IP6 (class 0xe0, hlim 255, next-header UDP (17) payload length: 219) fe80::200:f7ff:fef7:256.547 > fe80::b2b9:8aff:fe73:5a5c.546: [udp sum ok] dhcp6 advertise (xid=c04d67 (client-ID hwaddr type 1 b0b98a735a5c) (server-ID hwaddr/time type 1 time 708449505 a209da24f4bf) (IA_NA IAID:1 T1:1000 T2:2000 (IA_ADDR 2a02:168:2000:3c::21 pltime:3000 vltime:4000)) (DNS-server 2001:1620:2777:1::10 2001:1620:2777:2::20) (IA_PD IAID:1 T1:1000 T2:2000 (IA_PD-prefix 2a02:168:b998::/48 pltime:3000 vltime:4000)) (SNTP-servers 2001:1620:2777:d::2 2001:1620:2777:b::128) (Client-FQDN))
19:54:50.215805 IP6 (class 0xe0, hlim 1, next-header UDP (17) payload length: 163) fe80::20d:b9ff:fe61:6024.546 > ff02::1:2.547: [udp sum ok] dhcp6 relay-fwd (linkaddr=:: peeraddr=fe80::20d:b9ff:fe61:6024 (relay-message (dhcp6 renew (xid=e11e1e (client-ID hwaddr/time type 1 time 768135144 000db9616024) (server-ID hwaddr/time type 1 time 708449505 a209da24f4bf) (IA_NA IAID:0 T1:1000 T2:2000 (IA_ADDR 2a02:168:2000:3c::d pltime:3000 vltime:4000)) (elapsed-time 0) (option-request DNS-server DNS-search-list))) (interface-ID 73312e3638306368725f...))
19:54:50.322363 IP6 (flowlabel 0x535ad, hlim 1, next-header UDP (17) payload length: 183) fe80::b2b9:8aff:fe73:5a5c.546 > ff02::1:2.547: [udp sum ok] dhcp6 request (xid=fd9775 (elapsed-time 0) (option-request SIP-servers-domain SIP-servers-address DNS-server DNS-search-list SNTP-servers NTP-server AFTR-Name opt_67 opt_94 opt_95 opt_96) (client-ID hwaddr type 1 b0b98a735a5c) (server-ID hwaddr/time type 1 time 708449505 a209da24f4bf) (reconfigure-accept) (Client-FQDN) (IA_NA IAID:1 T1:0 T2:0 (IA_ADDR 2a02:168:2000:3c::21 pltime:3000 vltime:4000)) (IA_PD IAID:1 T1:0 T2:0 (IA_PD-prefix 2a02:168:b998::/48 pltime:3000 vltime:4000)))
19:54:50.341523 IP6 (class 0xe0, hlim 255, next-header UDP (17) payload length: 219) fe80::200:f7ff:fef7:256.547 > fe80::b2b9:8aff:fe73:5a5c.546: [udp sum ok] dhcp6 reply (xid=fd9775 (client-ID hwaddr type 1 b0b98a735a5c) (server-ID hwaddr/time type 1 time 708449505 a209da24f4bf) (IA_NA IAID:1 T1:1000 T2:2000 (IA_ADDR 2a02:168:2000:3c::21 pltime:3000 vltime:4000)) (DNS-server 2001:1620:2777:1::10 2001:1620:2777:2::20) (IA_PD IAID:1 T1:1000 T2:2000 (IA_PD-prefix 2a02:168:b998::/48 pltime:3000 vltime:4000)) (SNTP-servers 2001:1620:2777:d::2 2001:1620:2777:b::128) (Client-FQDN))
19:54:50.682250 IP6 (class 0xe0, hlim 1, next-header UDP (17) payload length: 164) fe80::20d:b9ff:fe61:6024.546 > ff02::1:2.547: [udp sum ok] dhcp6 relay-fwd (linkaddr=:: peeraddr=fe80::20d:b9ff:fe61:6024 (relay-message (dhcp6 renew (xid=f66720 (client-ID hwaddr/time type 1 time 768135144 000db9616024) (server-ID hwaddr/time type 1 time 708449505 a209da24f4bf) (elapsed-time 0) (option-request DNS-server DNS-search-list) (IA_PD IAID:0 T1:1000 T2:2000 (IA_PD-prefix 2a02:168:b9f8::/48 pltime:3000 vltime:4000)))) (interface-ID 73312e3638306368725f...))
^C
8 packets captured
8 packets received by filter
0 packets dropped by kernel

And then from the site that doesn't work

root@OpenWrt:~# tcpdump -vv -n -i eth0.2 portrange 546-547
tcpdump: listening on eth0.2, link-type EN10MB (Ethernet), snapshot length 262144 bytes
19:45:12.600619 IP6 (flowlabel 0xd8c97, hlim 1, next-header UDP (17) payload length: 110) fe80::b2b9:8aff:fe73:62a2.546 > ff02::1:2.547: [udp sum ok] dhcp6 solicit (xid=c1ba40 (elapsed-time 0) (option-request SIP-servers-domain SIP-servers-address DNS-server DNS-search-list SNTP-servers NTP-server AFTR-Name opt_67 opt_94 opt_95 opt_96 opt_82) (client-ID hwaddr type 1 b0b98a7362a2) (reconfigure-accept) (Client-FQDN) (IA_NA IAID:1 T1:0 T2:0) (IA_PD IAID:1 T1:0 T2:0))
19:45:13.782012 IP6 (flowlabel 0xd8c97, hlim 1, next-header UDP (17) payload length: 110) fe80::b2b9:8aff:fe73:62a2.546 > ff02::1:2.547: [udp sum ok] dhcp6 solicit (xid=c1ba40 (elapsed-time 118) (option-request SIP-servers-domain SIP-servers-address DNS-server DNS-search-list SNTP-servers NTP-server AFTR-Name opt_67 opt_94 opt_95 opt_96 opt_82) (client-ID hwaddr type 1 b0b98a7362a2) (reconfigure-accept) (Client-FQDN) (IA_NA IAID:1 T1:0 T2:0) (IA_PD IAID:1 T1:0 T2:0))
19:45:16.012264 IP6 (flowlabel 0xd8c97, hlim 1, next-header UDP (17) payload length: 110) fe80::b2b9:8aff:fe73:62a2.546 > ff02::1:2.547: [udp sum ok] dhcp6 solicit (xid=c1ba40 (elapsed-time 341) (option-request SIP-servers-domain SIP-servers-address DNS-server DNS-search-list SNTP-servers NTP-server AFTR-Name opt_67 opt_94 opt_95 opt_96 opt_82) (client-ID hwaddr type 1 b0b98a7362a2) (reconfigure-accept) (Client-FQDN) (IA_NA IAID:1 T1:0 T2:0) (IA_PD IAID:1 T1:0 T2:0))
19:45:19.472784 IP6 (flowlabel 0x42df3, hlim 1, next-header UDP (17) payload length: 111) fe80::21d:73ff:feb4:6bca.546 > ff02::1:2.547: [udp sum ok] dhcp6 solicit (xid=72ada3 (elapsed-time 65535) (option-request SIP-servers-domain SIP-servers-address DNS-server DNS-search-list SNTP-servers NTP-server AFTR-Name opt_67 opt_94 opt_95 opt_96 opt_82) (client-ID hwaddr type 1 001d73b46bca) (reconfigure-accept) (Client-FQDN) (IA_NA IAID:1 T1:0 T2:0) (IA_PD IAID:1 T1:0 T2:0))
19:45:20.412933 IP6 (flowlabel 0xd8c97, hlim 1, next-header UDP (17) payload length: 110) fe80::b2b9:8aff:fe73:62a2.546 > ff02::1:2.547: [udp sum ok] dhcp6 solicit (xid=c1ba40 (elapsed-time 781) (option-request SIP-servers-domain SIP-servers-address DNS-server DNS-search-list SNTP-servers NTP-server AFTR-Name opt_67 opt_94 opt_95 opt_96 opt_82) (client-ID hwaddr type 1 b0b98a7362a2) (reconfigure-accept) (Client-FQDN) (IA_NA IAID:1 T1:0 T2:0) (IA_PD IAID:1 T1:0 T2:0))
19:45:24.916776 IP6 (class 0xe0, hlim 255, next-header UDP (17) payload length: 231) fe80::f2b0:14ff:fec2:e98d.546 > ff02::1:2.547: [udp sum ok] dhcp6 relay-fwd (linkaddr=:: peeraddr=fe80::f2b0:14ff:fec2:e98d (relay-message (dhcp6 renew (xid=d44595 (elapsed-time 0) (client-ID hwaddr type 1 f0b014c2e98d) (server-ID hwaddr/time type 1 time 708449505 8a9a8c6cf4de) (IA_NA IAID:348318093 T1:1000 T2:2000 (IA_ADDR 2a02:168:2000:2e::11cd pltime:3000 vltime:4000)) (IA_PD IAID:348318093 T1:1000 T2:2000 (IA_PD-prefix 2a02:168:9d95::/48 pltime:3000 vltime:4000)) (reconfigure-accept) (option-request DNS-server NTP-server SNTP-servers IA_PD IA_NA vendor-specific-info opt_82 opt_83 opt_86) (vendor-class))) (interface-ID 73312e36383070706c5f...))
19:45:27.629472 IP6 (hlim 1, next-header UDP (17) payload length: 104) fe80::52e0:39ff:fe35:bdfc.546 > ff02::1:2.547: [udp sum ok] dhcp6 renew (xid=75bf2d (client-ID hwaddr type 1 50e03935bdfc) (server-ID hwaddr/time type 1 time 708449505 a209da24f4bf) (reconfigure-accept) (IA_NA IAID:959823360 T1:1000 T2:2000 (IA_ADDR 2a02:168:2000:2e::11 pltime:3000 vltime:4000)) (elapsed-time 0) (option-request DNS-server))
19:45:27.629472 IP6 (hlim 1, next-header UDP (17) payload length: 105) fe80::52e0:39ff:fe35:bdfc.546 > ff02::1:2.547: [udp sum ok] dhcp6 renew (xid=8de195 (client-ID hwaddr type 1 50e03935bdfc) (server-ID hwaddr/time type 1 time 708449505 a209da24f4bf) (reconfigure-accept) (elapsed-time 0) (option-request DNS-server) (IA_PD IAID:959823381 T1:1000 T2:2000 (IA_PD-prefix 2a02:168:9c02::/48 pltime:3000 vltime:4000)))
19:45:29.532026 IP6 (flowlabel 0xd8c97, hlim 1, next-header UDP (17) payload length: 110) fe80::b2b9:8aff:fe73:62a2.546 > ff02::1:2.547: [udp sum ok] dhcp6 solicit (xid=c1ba40 (elapsed-time 1693) (option-request SIP-servers-domain SIP-servers-address DNS-server DNS-search-list SNTP-servers NTP-server AFTR-Name opt_67 opt_94 opt_95 opt_96 opt_82) (client-ID hwaddr type 1 b0b98a7362a2) (reconfigure-accept) (Client-FQDN) (IA_NA IAID:1 T1:0 T2:0) (IA_PD IAID:1 T1:0 T2:0))
19:45:44.964185 IP6 (class 0xe0, hlim 255, next-header UDP (17) payload length: 230) fe80::b2f2:8ff:feaf:ed7.546 > ff02::1:2.547: [udp sum ok] dhcp6 relay-fwd (linkaddr=:: peeraddr=fe80::b2f2:8ff:feaf:ed7 (relay-message (dhcp6 renew (xid=75216d (elapsed-time 0) (client-ID hwaddr type 1 b0f208af0ed7) (server-ID hwaddr/time type 1 time 708449505 8a9a8c6cf4de) (IA_NA IAID:145690327 T1:1000 T2:2000 (IA_ADDR 2a02:168:2000:2e::1be pltime:3000 vltime:4000)) (IA_PD IAID:145690327 T1:1000 T2:2000 (IA_PD-prefix 2a02:168:9d97::/48 pltime:3000 vltime:4000)) (reconfigure-accept) (option-request DNS-server NTP-server SNTP-servers IA_PD IA_NA vendor-specific-info opt_82 opt_83 opt_86) (vendor-class))) (interface-ID 73312e36383070706c5f...))
19:45:47.852008 IP6 (flowlabel 0xd8c97, hlim 1, next-header UDP (17) payload length: 110) fe80::b2b9:8aff:fe73:62a2.546 > ff02::1:2.547: [udp sum ok] dhcp6 solicit (xid=c1ba40 (elapsed-time 3525) (option-request SIP-servers-domain SIP-servers-address DNS-server DNS-search-list SNTP-servers NTP-server AFTR-Name opt_67 opt_94 opt_95 opt_96 opt_82) (client-ID hwaddr type 1 b0b98a7362a2) (reconfigure-accept) (Client-FQDN) (IA_NA IAID:1 T1:0 T2:0) (IA_PD IAID:1 T1:0 T2:0))
19:46:03.634689 IP6 (hlim 255, next-header UDP (17) payload length: 173) fe80::eadf:70ff:fefe:a28d.546 > ff02::1:2.547: [udp sum ok] dhcp6 renew (xid=a6610c (elapsed-time 0) (client-ID hwaddr type 1 e8df70fea28d) (server-ID hwaddr/time type 1 time 708449505 8a9a8c6cf4de) (IA_NA IAID:1895735949 T1:1000 T2:2000 (IA_ADDR 2a02:168:2000:2e::10c pltime:3000 vltime:4000)) (IA_PD IAID:1895735949 T1:1000 T2:2000 (IA_PD-prefix 2a02:168:9df9::/48 pltime:3000 vltime:4000)) (reconfigure-accept) (option-request DNS-server NTP-server SNTP-servers IA_PD IA_NA vendor-specific-info opt_82 opt_83 opt_86) (vendor-class))
19:46:04.208975 IP6 (hlim 1, next-header UDP (17) payload length: 104) fe80::5e64:8eff:feaf:106b.546 > ff02::1:2.547: [udp sum ok] dhcp6 renew (xid=96d701 (client-ID hwaddr type 1 5c648eaf106b) (server-ID hwaddr/time type 1 time 708449505 8a9a8c6cf4de) (reconfigure-accept) (IA_NA IAID:2393837679 T1:1000 T2:2000 (IA_ADDR 2a02:168:2000:2e::169 pltime:3000 vltime:4000)) (elapsed-time 0) (option-request DNS-server))
19:46:04.208975 IP6 (hlim 1, next-header UDP (17) payload length: 105) fe80::5e64:8eff:feaf:106b.546 > ff02::1:2.547: [udp sum ok] dhcp6 renew (xid=9cb1de (client-ID hwaddr type 1 5c648eaf106b) (server-ID hwaddr/time type 1 time 708449505 8a9a8c6cf4de) (reconfigure-accept) (elapsed-time 0) (option-request DNS-server) (IA_PD IAID:2393837700 T1:1000 T2:2000 (IA_PD-prefix 2a02:168:9c24::/48 pltime:3000 vltime:4000)))
19:46:10.504558 IP6 (hlim 1, next-header UDP (17) payload length: 106) fe80::669d:99ff:feb2:2241.546 > ff02::1:2.547: [udp sum ok] dhcp6 renew (xid=e78db3 (client-ID hwaddr/time type 1 time 765739077 649d99b22240) (server-ID hwaddr/time type 1 time 708449505 a209da24f4bf) (IA_NA IAID:2 T1:1000 T2:2000 (IA_ADDR 2a02:168:2000:2e::13 pltime:3000 vltime:4000)) (elapsed-time 0) (option-request DNS-server DNS-search-list))
19:46:10.923871 IP6 (class 0xe0, hlim 255, next-header UDP (17) payload length: 230) fe80::de15:c8ff:feaf:c45c.546 > ff02::1:2.547: [udp sum ok] dhcp6 relay-fwd (linkaddr=:: peeraddr=fe80::de15:c8ff:feaf:c45c (relay-message (dhcp6 renew (xid=eff44f (elapsed-time 0) (client-ID hwaddr type 1 dc15c8afc45c) (server-ID hwaddr/time type 1 time 708449505 a209da24f4bf) (IA_NA IAID:3366962268 T1:1000 T2:2000 (IA_ADDR 2a02:168:2000:2e::1f pltime:3000 vltime:4000)) (IA_PD IAID:3366962268 T1:1000 T2:2000 (IA_PD-prefix 2a02:168:9d98::/48 pltime:3000 vltime:4000)) (reconfigure-accept) (option-request DNS-server NTP-server SNTP-servers IA_PD IA_NA vendor-specific-info opt_82 opt_83 opt_86) (vendor-class))) (interface-ID 73312e36383070706c5f...))
19:46:18.226742 IP6 (hlim 1, next-header UDP (17) payload length: 104) fe80::5e64:8eff:feab:3ddf.546 > ff02::1:2.547: [udp sum ok] dhcp6 renew (xid=5fa6f9 (client-ID hwaddr type 1 5c648eab3ddf) (server-ID hwaddr/time type 1 time 708449505 8a9a8c6cf4de) (reconfigure-accept) (IA_NA IAID:2393587171 T1:1000 T2:2000 (IA_ADDR 2a02:168:2000:2e::168 pltime:3000 vltime:4000)) (elapsed-time 0) (option-request DNS-server))
19:46:18.226742 IP6 (hlim 1, next-header UDP (17) payload length: 105) fe80::5e64:8eff:feab:3ddf.546 > ff02::1:2.547: [udp sum ok] dhcp6 renew (xid=878c3c (client-ID hwaddr type 1 5c648eab3ddf) (server-ID hwaddr/time type 1 time 708449505 8a9a8c6cf4de) (reconfigure-accept) (elapsed-time 0) (option-request DNS-server) (IA_PD IAID:2393587192 T1:1000 T2:2000 (IA_PD-prefix 2a02:168:9c23::/48 pltime:3000 vltime:4000)))
19:46:18.365361 IP6 (hlim 1, next-header UDP (17) payload length: 107) fe80::20d:b9ff:fe41:7e30.546 > ff02::1:2.547: [udp sum ok] dhcp6 renew (xid=c823e2 (client-ID hwaddr/time type 1 time 555582101 000db9417e30) (server-ID hwaddr/time type 1 time 708449505 a209da24f4bf) (elapsed-time 0) (option-request DNS-server DNS-search-list) (IA_PD IAID:0 T1:1000 T2:2000 (IA_PD-prefix 2a02:168:9daf::/48 pltime:3000 vltime:4000)))
19:46:20.844084 IP6 (hlim 1, next-header UDP (17) payload length: 104) fe80::5e64:8eff:feab:ae0b.546 > ff02::1:2.547: [udp sum ok] dhcp6 renew (xid=555bb9 (client-ID hwaddr type 1 5c648eabae0b) (server-ID hwaddr/time type 1 time 708449505 8a9a8c6cf4de) (reconfigure-accept) (IA_NA IAID:2393615887 T1:1000 T2:2000 (IA_ADDR 2a02:168:2000:2e::16b pltime:3000 vltime:4000)) (elapsed-time 0) (option-request DNS-server))
19:46:20.844085 IP6 (hlim 1, next-header UDP (17) payload length: 105) fe80::5e64:8eff:feab:ae0b.546 > ff02::1:2.547: [udp sum ok] dhcp6 renew (xid=8b086f (client-ID hwaddr type 1 5c648eabae0b) (server-ID hwaddr/time type 1 time 708449505 8a9a8c6cf4de) (reconfigure-accept) (elapsed-time 0) (option-request DNS-server) (IA_PD IAID:2393615908 T1:1000 T2:2000 (IA_PD-prefix 2a02:168:9c26::/48 pltime:3000 vltime:4000)))
19:46:25.452040 IP6 (flowlabel 0xd8c97, hlim 1, next-header UDP (17) payload length: 110) fe80::b2b9:8aff:fe73:62a2.546 > ff02::1:2.547: [udp sum ok] dhcp6 solicit (xid=c1ba40 (elapsed-time 7285) (option-request SIP-servers-domain SIP-servers-address DNS-server DNS-search-list SNTP-servers NTP-server AFTR-Name opt_67 opt_94 opt_95 opt_96 opt_82) (client-ID hwaddr type 1 b0b98a7362a2) (reconfigure-accept) (Client-FQDN) (IA_NA IAID:1 T1:0 T2:0) (IA_PD IAID:1 T1:0 T2:0))
19:46:30.672261 IP6 (hlim 1, next-header UDP (17) payload length: 104) fe80::fa0d:a9ff:febd:5e20.546 > ff02::1:2.547: [udp sum ok] dhcp6 renew (xid=53bd29 (client-ID hwaddr type 1 f80da9bd5e20) (server-ID hwaddr/time type 1 time 708449505 a209da24f4bf) (reconfigure-accept) (IA_NA IAID:2847759908 T1:1000 T2:2000 (IA_ADDR 2a02:168:2000:2e::c pltime:3000 vltime:4000)) (elapsed-time 0) (option-request DNS-server))
19:46:30.672262 IP6 (hlim 1, next-header UDP (17) payload length: 105) fe80::fa0d:a9ff:febd:5e20.546 > ff02::1:2.547: [udp sum ok] dhcp6 renew (xid=9f806b (client-ID hwaddr type 1 f80da9bd5e20) (server-ID hwaddr/time type 1 time 708449505 a209da24f4bf) (reconfigure-accept) (elapsed-time 0) (option-request DNS-server) (IA_PD IAID:2847759929 T1:1000 T2:2000 (IA_PD-prefix 2a02:168:9c01::/48 pltime:3000 vltime:4000)))

^C
24 packets captured
25 packets received by filter
0 packets dropped by kernel

The conclusion looks the same to me. At the site that doesn't work it's basically making dhcpv6 requests and getting no answer in return.
Does this output make it clear the issue is on the ISP side ?

DBAA · October 3, 2024, 9:16pm

Note if the WAN IPv6 address is working you can turn on IPv6 Masquerading to get some IPv6 connectivity from the LAN until you get PD working. The settings are in the wan firewall zone under Advanced Settings.

moeller0 · October 3, 2024, 9:37pm

These two traces seem not to capture the exact same state in the exchange, but I agree it looks like in the second case you send a request to the multicast address and get no response...
How is the whole thing setup, with PPPoE or is IPv4 also handled by DHCP(v4)?

billybob · November 4, 2024, 9:48pm

@moeller0 everything is simply DHCP or DHCPv6, no PPPoE

I'm still trying to get this sorted with the ISP.
One last test I'd like to do to is a connectivity test with socat

So far I've successfully listened on various ports with a command along the lines of
socat - UDP6-LISTEN:25,fork,reuseaddr,ipv6only
Using a another machine on a different LAN, I've then successfully sent sent text across with
socat - UDP6:[2a02:168:xxx]:25
where xxx is the router's public ipv6. It is the /64 that gets handed to the router and the result I get when running curl ipv6.icanhazip.com.
This works, and I can see the text being sent across the WAN to my router (the one that doesn't get an IPV6 prefix).

Now I can't seem to do a connectivity test on port 546, because there is understandably a dhcpv6-client using it. lsof -i udp:546 tells me the process is odhcp6c. Disabling odhcpd with /etc/init.d/odhcpd stop does not stop this process, and if I try to kill it it just restarts.

Is there a way I can temporarily stop the odhcp6c process to do a connectivity test on port 546 ?

Arduous · December 15, 2024, 4:37pm

Hello, any chance you could share with me your init7 ipv6 configuration in /etc/config/network? Many thanks.

billybob · January 12, 2025, 8:22pm

Sure. Do not that in the meantime it was confirmed that the problem was on the ISP side, and they have fixed it since. IPv6 prefix delegation works, all clients on the LAN get an IPv6 from the same prefix and have IPv6 connectivity
Thanks to everyone that helped troubleshooting. I learned quite a few things about IPv6, tcpdump and socat.

The router is now on 23.05.5, and I don't think there is any change compared to the stock network config:

config interface 'loopback'
	option device 'lo'
	option proto 'static'
	option ipaddr '127.0.0.1'
	option netmask '255.0.0.0'

config globals 'globals'
	option ula_prefix 'fdc9:a015:2e49::/48'

config device
	option name 'br-lan'
	option type 'bridge'
	list ports 'lan1'
	list ports 'lan2'
	list ports 'lan3'
	list ports 'lan4'

config interface 'lan'
	option device 'br-lan'
	option proto 'static'
	option ipaddr '192.168.1.1'
	option netmask '255.255.255.0'
	option ip6assign '60'

config interface 'wan'
	option device 'wan'
	option proto 'dhcp'

config interface 'wan6'
	option device 'wan'
	option proto 'dhcpv6'

Arduous · January 15, 2025, 1:42pm

Thank you. For some reason, I replied to myself a few weeks ago, but never published the message. Basically, It worked out of the box. Many thanks for your follow up.

system · January 25, 2025, 1:43pm

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