Dhcp Troubleshooting; Troubleshooting Ipv6 Dhcp Relay - Avaya 8800 Troubleshooting Manual

Upper layer troubleshooting

DHCP troubleshooting

This section describes methods to troubleshoot the following Dynamic Host Configuration
Protocol (DHCP) scenarios:
• Client cannot obtain a DHCP address when in the same subnet.
• Client cannot obtain a DHCP address when in different subnets.
When the DHCP server and client are on the different subnets or VLANs, the router must be
configured as a DHCP Relay Agent and is responsible for forwarding DHCP Requests to the
DHCP server. Extra troubleshooting steps (not included here) are needed to troubleshoot the
DHCP Relay Agent.
For a DHCP Relay recovery flowchart, see
Procedure steps
1. Check the physical connectivity between the DHCP client and server.
2. Verify network connectivity by configuring a static IP address on a client
3. Attempt to obtain an IP address from the DHCP server by manually forcing the client
4. Obtain an IP address on the same subnet or VLAN as the DHCP server.
5. Confirm the DHCP Relay Agent configuration is correct
6. Obtain sniffer traces where the traffic ingresses and egresses the switch and also

Troubleshooting IPv6 DHCP Relay

For a DHCP Relay recovery flowchart, see
438 Troubleshooting
workstation.
If the workstation is still not able to reach the network, the problem is not DHCP.
Start troubleshooting network connectivity.
to send a DHCP request.
If the client gets an IP address after the PC has completed its startup, the issue is
not the DHCP server.
If DHCP is working on the same subnet or VLAN as the DHCP server, the DHCP
issue may be with the DHCP Relay Agent. If the issue is still there, the problem may
be with the DHCP server.
on the client side of the network.
Comments? infodev@avaya.com
DHCP Relay failure on page 336.
DHCP Relay failure on page 336
July 2013