SNR S2989G-48TX [521/553] Dhcpv6 troubleshooting

S2989G-24TX Operation Manual

Chapter 11 IPv6 Configuration

11-11

11.1.7

DHCPv6 Troubleshooting

If the DHCPv6 clients cannot obtain IPv6 addresses and other network parameters,

the following procedures can be followed when DHCPv6 client hardware and cables have

been verified ok:

 Verify the DHCPv6 server is running, start the related DHCP v6 server function if not

running;

 If the DHCPv6 clients and servers are not in the same physical network, verify the

router responsible for DHCPv6 packet forwarding has DHCPv6 relay function. If

DHCPv6 relay is not available for the intermediate router, it is recommended to

replace the router or upgrade its software to one that has a DHCPv6 relay function;

 Sometimes hosts are connected to the DHCPv6 enabled switches, but can not get

IPv6 addresses. In this situation, it should be checked first whether the ports which

the hosts are connected to, are connected with the port which the DHCPv6 server is

connected to. If connected directly, it should be checked then whether the IPv6

address pool of the VLAN which the port belongs to, is in the same subnet with the

address pool configure in the DHCPv6 server; If not connected directly, and any layer

three DHCPv6 relay is configured between the hosts and the DHCPv6 server, it

should be checked first whether an valid IPv6 address has been configured for the

switch interface which the hosts are connected to. If not configured, configure an valid

IPv6 address. If configured, it should be checked whether the configured IPv6

address is in the same subnet with the DHCPv6 server. If not, please add it to the

address pool.

11.2

DHCPv6 option37, 38

11.2.1

Introduction to DHCPv6 option37, 38

DHCPv6 (Dynamic Host Configuration Protocol for IPv6) is designed for IPv6 address

scheme and is used for assigning IPv6 prefixes, IPv6 addresses and other configuration

parameters to hosts.

When DHCPv6 client wants to request address and configure parameter of DHCPv6

server from different link, it needs to communicate with server through DHCPv6 relay

agent. DHCPv6 message received by relay agent node is reencapsulated to be relay-

forward packets and they are forwarded to the server which sends the relay-reply packets

to DHCPv6 relay agent node in different link, after that, relay agent node restores

DHCPv6 message to DHCPv6 client to finish communication between client and server.