Enterasys Networks CSX6000, CSX5500, CSX7000 manual USER’S Guide

USER’S GUIDE

In this configuration, the DHCP Client is able to obtain its IP address from the DHCP Server, using the Relay Agent contained in the IP Router on the client’s LAN (“Ruby”).

Shortly after a DHCP Client is powered on, it will attempt to get its IP address from a DHCP Server. If it is successful, its IP-related features (e.g., ping, telnet, etc.) will become operational. If the client could not obtain its IP address, it will retry periodically to do so.

1.From the DHCP Client, attempt to ping the Relay Agent (“Ruby”) that is on the same LAN:

C:\> ping 204.157.42.168 <return>

Pinging 204.157.42.168 with 32 bytes of data:

Reply from 204.157.42.168: bytes=32 time=2ms TTL=64

Reply from 204.157.42.168: bytes=32 time=2ms TTL=64

Reply from 204.157.42.168: bytes=32 time=1ms TTL=64

Reply from 204.157.42.168: bytes=32 time=2ms TTL=64

A response of this form indicates that the IP-related features of this client are enabled. Therefore, it has successfully obtained an IP address from the DHCP Server.

2.If the ping attempt resulted in something like the following, the client was not able to obtain its IP address from the DHCP Server:

C:\> ping 204.157.42.168

Pinging 204.157.42.168 with 32 bytes of data:

Destination host unreachable.

Destination host unreachable.

Destination host unreachable.

Destination host unreachable.

If this is the case, try the following:

a.Check the DHCP configuration. This can be done by using CFGEDIT, or by using the dhcp Manage Mode command.

b.Make sure that the Relay Agent is enabled on the desired machine. Check the report log. A message is written to it by the DHCP Relay Agent when it has been successfully enabled.

c.Make sure that the DHCP Relay Agent is properly configured. There must be a relay destination configured for the desired DHCP Server, or for the next DHCP Relay Agent to go through.

d.If the machine being configured is an intermediate DHCP Relay Agent, make sure that the Hop Threshold is large enough to allow the number of Relay Agent “hops” between the DHCP Client and the DHCP Server.

e.From the DHCP Server, you should be able to “ping” the DHCP Relay Agent closest to the DHCP Client. If you cannot, you need to add static routes that allow you to do so.

f.From the DHCP Relay Agent closest to the DHCP Client, you should be able to “ping” the DHCP Server. If you cannot, you need to add static routes that allow you to do so.

g.The DHCP Server must be configured to distribute addresses to clients on the DHCP Client’s subnetwork.

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