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My dhcp server using isc dhcpd v4.3.6,dhcpd6.conf file:

 subnet6 2001:xx:xxx:xxx::/64 {
 range6                  2001:xx:xxx:xxx::10 2001:xx:xxx:xxx::ffff;
 option dhcp6.name-servers          2001:xxx:xx::131;
 default-lease-time                   3600;
 max-lease-time                       3600;
 always-broadcast on;
 }

Step1:When PC and dhcpv6 server in the same subnet: PC can get a ipv6 address from dhcpv6 server pool.I can see solicit,advertise,request and reply packet,everything is fine.

Step2:When PC and dhcpv6 server NOT in the same subnet: My network is PC-Router-dhcp server,the router is huawei or H3C router. The router conf is:

interface Vlanif200
 ipv6 enable
 ipv6 address 2001:xx:xx:xx:xxx::1/64
 ipv6 nd ra prefix 2001:xx:xx:xx::/64 28800 28800
 undo ipv6 nd ra halt
 ipv6 nd autoconfig managed-address-flag
 ipv6 nd autoconfig other-flag
 dhcpv6 relay destination 2001:xx:xxx:xx:xxx

The PC can't get ipv6 address from dhcpv6 server.Capture packet on pc,i just saw PC sent a solicit packet and got a advertise packet from relay router,but the pc didn't send a request packet,Why???

The packets like this: packets1 solicit advertise

Skytiger
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  • Please include details from the packet capture. And please include bits 48 to 64 of your configuration so we can validate subnetting related problems. – Sander Steffann Feb 22 '18 at 07:24
  • Thanks for your answer,i added 3 pics link in my question – Skytiger Feb 22 '18 at 08:56
  • The "solicit" message is sent as `ip6-allrouters` multicast, but the "advertise" message is targeted to a link-local address `fe80::8483:6e04:d52d:b0bc`. Is this link-local address correct for the PC and is the PC configured to accept link-local traffic? If that's OK, review all the information in the "advertise" message: is it all valid for the subnet the PC is in? You might need a separate `subnet6` declaration for the other subnet. What do the router advertisements say in that subnet, does it match the existing `subnet6` declaration? – telcoM Feb 22 '18 at 13:14

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