DHCP - 6500

[bimalnp4me]

Hi All,

i have this message "DHCP Timeout"on few cisco IP Phones .

try to assign IP manually and it's working fine.. seems DHCP not giving IP's to those..

6500 have configured as DHCP pool..

any idea how to trouble shoot?

[Steve Fuller]

Hi,

Do you have spanning-tree portfast edge or more probably spanning-tree portfast edge trunk configured on all the switchports that the phones are connected to? This is often a cause of devices not getting DHCP addresses.

Also where are the phones in relation to the DHCP server and if they're not on the same switch or VLAN, do you have the ip helper-address command configured such that the DHCP request is correctly forwarded to the DHCP server?

Regards

[bimalnp4me]

The phones and DHCP are not in the same network range..

the phones  are connected to different switches ...

DHCP was releasing IP's from 10.10.15.0/24 to IP Phones..

not the total DHCP pool is utilized..

phones are working yesterday and work after add manual IP ..

(6500 restart after 3 years)

[Steve Fuller]

Hi,

Since the reboot are any phones still able to get an IP address from the DHCP pool configured on the Catalyst 6500? If so are these phones in a different subnet to those phones that are not able to get an IP address?

If those phones that are not working are in a different subnet, is the ip helper-address on the VLAN interface correct i.e., forwarding the DHCP request to the IP address assigned to the Catalyst 6500?

Can you provide a little more detail of your topology i.e., how the switches that the phones are attached to are connected to the Catalyst 6500, where the routing takes place for the subnet the phones are on etc.?

Regards