DHCP Service on 4510 - Lease

Unanswered Question
May 18th, 2009

i have got this configuration on my 4510 , this works fine , but the lease time is not holding good, every time a PC reboots , get's a different IP address

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ip dhcp pool 50

network 10.202.50.0 255.255.255.0

default-router 10.202.50.254

domain-name x.com

dns-server x.x.x.x x.x.x.x

netbios-name-server x.x.x.x x.x.x.x

option 60 ascii "OptiPoint;OptiIpPhone"

option 43 hex 010a.5369.656d.656e.7300.0000.0204.0000.0073.00ff

lease 30

!

Please help me to fix the problem .

Regards

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jimmysands73_2 Mon, 05/18/2009 - 14:22

When it reboots is it possible that the pc is also releasing that address, then while in the process of rebooting, another client is taking that address? Comparing leases to MACs should show this. Just a guess.

jimmysands73_2 Mon, 05/18/2009 - 14:22

When it reboots is it possible that the pc is also releasing that address, then while in the process of rebooting, another client is taking that address? Comparing leases to MACs should show this. Just a guess.

jeff.carr Tue, 05/19/2009 - 08:33

A DHCP lease is the amount of time that the DHCP server grants to the DHCP client permission to use a particular IP address. This does not necessarily dictate that the IP address will be reserved for the duration of the lease and only be used by that client.

It sounds like you would like for the PC to continue using the same IP address without statically assigning it in the TCP/IP settings. Depending on the IOS version, you can probably configure the switch to recognize the client by MAC address and provide the same IP address every time. Here is an example of the config settings.

> ip dhcp pool PC0001

> host 192.168.100.20 255.255.255.0

> client-identifier aabb.ccdd.eeff

> client-name PC0001

> default-router 192.168.100.1

> domain-name x.com

> dns-server 192.168.100.10

You will need to create a separate DHCP pool for each host. You can also keep your existing DHCP pool in production, just edit it appropriately so that IP addresses are not included in multiple pools.

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