Failed to get /64 prefixes of IPv6 address in 94002

[haohui]

It seems that Sonic only assigns a /128 IPv6 address in DHCPv6 in 94002. Here are the results of tcpdump:

Code: Select all

 00:00:00.002095 IP6 (flowlabel 0x5e2a6, hlim 1, next-header UDP (17) payload length: 130) fe80::6a05:caff:fexx:xxxx.dhcpv6-client > ff02::1:2.dhcpv6-server: [bad udp cksum 0x9ab7 -> 0xe679!] dhcp6 solicit (xid=b7e84c (rapid-commit) (IA_NA IAID:2115787654 T1:0 T2:0) (Client-FQDN) (IA_PD IAID:2115787654 T1:0 T2:0 (IA_PD-prefix ::/64 pltime:0 vltime:0)) (option-request DNS-server DNS-search-list NTP-server SNTP-servers rapid-commit) (client-ID vid 0000ab1136c07f3d) (elapsed-time 0))
 00:00:00.210603 IP6 (class 0xc0, hlim 64, next-header UDP (17) payload length: 192) fe80::561e:56ff:fe9a:b8c0.dhcpv6-server > fe80::6a05:caff:fexx:xxxx.dhcpv6-client: [udp sum ok] dhcp6 advertise (xid=b7e84c (client-ID vid 0000ab1136c07f3d) (server-ID vid 0000058335343a31) (IA_NA IAID:2115787654 T1:10800 T2:17280 (IA_ADDR xxxx:xxxx:xxxx:xx::xx pltime:21600 vltime:21600)) (IA_PD IAID:2115787654 T1:0 T2:0 (status-code NoPrefixAvail)) (DNS-server ns1.sonic.net ns2.sonic.net))

I've tried to request a prefix of /58,/60, /62, and /64 but the DHCPv6 server from Sonic reports NoPrefixAvail. Any ideas?

Thanks.

[mgoldburg]

Sonic delegates a /56 per this viewtopic.php?t=17498&start=10 . Try requesting a /56.

[brandonc]

It seems that Sonic only assigns a /128 IPv6 address in DHCPv6 in 94002. Here are the results of tcpdump:

Code: Select all

 00:00:00.002095 IP6 (flowlabel 0x5e2a6, hlim 1, next-header UDP (17) payload length: 130) fe80::6a05:caff:fexx:xxxx.dhcpv6-client > ff02::1:2.dhcpv6-server: [bad udp cksum 0x9ab7 -> 0xe679!] dhcp6 solicit (xid=b7e84c (rapid-commit) (IA_NA IAID:2115787654 T1:0 T2:0) (Client-FQDN) (IA_PD IAID:2115787654 T1:0 T2:0 (IA_PD-prefix ::/64 pltime:0 vltime:0)) (option-request DNS-server DNS-search-list NTP-server SNTP-servers rapid-commit) (client-ID vid 0000ab1136c07f3d) (elapsed-time 0))
 00:00:00.210603 IP6 (class 0xc0, hlim 64, next-header UDP (17) payload length: 192) fe80::561e:56ff:fe9a:b8c0.dhcpv6-server > fe80::6a05:caff:fexx:xxxx.dhcpv6-client: [udp sum ok] dhcp6 advertise (xid=b7e84c (client-ID vid 0000ab1136c07f3d) (server-ID vid 0000058335343a31) (IA_NA IAID:2115787654 T1:10800 T2:17280 (IA_ADDR xxxx:xxxx:xxxx:xx::xx pltime:21600 vltime:21600)) (IA_PD IAID:2115787654 T1:0 T2:0 (status-code NoPrefixAvail)) (DNS-server ns1.sonic.net ns2.sonic.net))

I've tried to request a prefix of /58,/60, /62, and /64 but the DHCPv6 server from Sonic reports NoPrefixAvail. Any ideas?

Thanks.

Hi there,

As mentioned above, we delegate /56 addresses for IPv6, not /64. If you request a /56 it should work as expected.

Kind regards,

[haohui]

Thanks for the reply. Trying with /56 does not work either:

Code: Select all

 00:00:00.002341 IP6 (flowlabel 0x5e2a6, hlim 1, next-header UDP (17) payload length: 130) fe80::6a05:caff:fexx:xxxx.dhcpv6-client > ff02::1:2.dhcpv6-server: [bad udp cksum 0x9ab7 -> 0x2737!] dhcp6 solicit (xid=73a7db (rapid-commit) (IA_NA IAID:2115787654 T1:0 T2:0) (Client-FQDN) (IA_PD IAID:2115787654 T1:0 T2:0 (IA_PD-prefix ::/56 pltime:0 vltime:0)) (option-request DNS-server DNS-search-list NTP-server SNTP-servers rapid-commit) (client-ID vid 0000ab1136c07f3d) (elapsed-time 0))
 00:00:00.094660 IP6 (class 0xc0, hlim 64, next-header UDP (17) payload length: 192) fe80::561e:56ff:fe9a:b8c0.dhcpv6-server > fe80::6a05:caff:fe43:6954.dhcpv6-client: [udp sum ok] dhcp6 advertise (xid=73a7db (client-ID vid 0000ab1136c07f3d) (server-ID vid 0000058335343a31) (IA_NA IAID:2115787654 T1:10800 T2:17280 (IA_ADDR xxxx:xxxx:xxxx:xx::xx pltime:21600 vltime:21600)) (IA_PD IAID:2115787654 T1:0 T2:0 (status-code NoPrefixAvail)) (DNS-server ns1.sonic.net ns2.sonic.net))
 

[mgoldburg]

Thanks for the reply. Trying with /56 does not work either:

Long shot, but ... any chance that you have a second device that is also soliciting prefixes, maybe a cascaded router? I had a situation once with a setup that looked like

ONT -- router 1 -- router 2

Router 1 was meant to get the delegated prefix and solicited for it, but router 2 was set up to solicit prefixes, too. The two routers were "fighting" for prefixes from the upstream setup. Router 2 would occasionally get the prefix and router 1 would get the same NoPrefixAvail message. Disabling solicitation on router 2 solved the problem.

[haohui]

I can confirm nothing funny is going on.. tcpdump only shows the traffic from one machine which is directly connect to the ONT

Thanks for the reply. Trying with /56 does not work either:

Long shot, but ... any chance that you have a second device that is also soliciting prefixes, maybe a cascaded router? I had a situation once with a setup that looked like

ONT -- router 1 -- router 2

Router 1 was meant to get the delegated prefix and solicited for it, but router 2 was set up to solicit prefixes, too. The two routers were "fighting" for prefixes from the upstream setup. Router 2 would occasionally get the prefix and router 1 would get the same NoPrefixAvail message. Disabling solicitation on router 2 solved the problem.

[brandonc]

I can confirm nothing funny is going on.. tcpdump only shows the traffic from one machine which is directly connect to the ONT

Thanks for the reply. Trying with /56 does not work either:

Long shot, but ... any chance that you have a second device that is also soliciting prefixes, maybe a cascaded router? I had a situation once with a setup that looked like

ONT -- router 1 -- router 2

Router 1 was meant to get the delegated prefix and solicited for it, but router 2 was set up to solicit prefixes, too. The two routers were "fighting" for prefixes from the upstream setup. Router 2 would occasionally get the prefix and router 1 would get the same NoPrefixAvail message. Disabling solicitation on router 2 solved the problem.

I'm sorry to hear that you're still not pulling an IPv6 address. I double-checked things on our end and I can confirm that I see multiple other users on the same card servicing your address that are pulling a /56 addresses. I would suggest checking your router's configuration to make sure you didn't overlook anything.

Kind regards,