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MoheyElbaz
Beginner

CUCM 12.5 DHCP TIME OUT

Hello,

 

i hope all are fine,

I have issue with Cisco Call Manager 12.5 

I have CMCM 12.5 + 2960 Switch + 7861 IP Phone + Mikrotik Router

I connected all together using VLAN 105 with 2 access ports and one trunk port for router.

I enabled the DHCP service  on CUCM.

 

When trying to get IP from CMCM the phone can't get IP with DHCP TIME OUT message.

2 ACCEPTED SOLUTIONS

Accepted Solutions
Roger Kallberg
VIP Advisor

The DHCP service on CM is notorious for not working good. You’d be much better of if you would use any other system to provide this service. It will save you a lot of time and effort, instead of trying to get the service to work on CM.



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Example switch configuration took fro my lab.

 

TO exclude the address from 1-100 i used DHCP exclude command.

ip dhcp excluded-address 10.60.56.1 10.60.56.100

 

ip dhcp pool Voice

 network 10.60.51.0 255.255.255.0

 default-router 10.60.51.1 

 option 150 ip 10.60.51.10 



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View solution in original post

19 REPLIES 19
Nithin Eluvathingal
VIP Advisor

Have you provided all required informations on CUCM DHCP scope( default gateway, mask etc..). Are you Able to ping CUCM from your default gateway and the other way?

 

On the switch port where you connect the phone, configure voice vlan 105. Does the phone shows operational vlan as 105. 

 

 

 

 

 

 

 

 

 



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Dear Nithin,

Thnx for your reply,

Actually the network is fine, in static mode the phone is registering, but there is DHCP is not responding.

Check if the dhcp services are running on CUCM and make sure you configured dhcp server and subnet properly. 

Check the Ip helper address.

 

 

Sample IP Helper configuration.

 

interface Vlan51

  ip address 10.60.51.1 255.255.255.0

 ip helper-address 10.60.51.10

 

 

CUCM DHCP configuration screenshots.

 

Screenshot 2021-04-25 at 1.12.57 PM.pngScreenshot 2021-04-24 at 8.38.44 PM.pngScreenshot 2021-04-25 at 1.14.38 PM.png

 

 



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Thanks for your support,

but all solutions not working,

kindly find screen shoots below, Mikrotik router just for access the CM page there is no DHCP server enabled on it.

I changed the VM nic to VLAN 105 and one phone connected to Trunk port one on Access port.

 

dhcp_s_2.PNGsw.PNGcm_serv.PNGdhcp_s_1.PNG

Your Primary router address configured on CUCM page is wrong. its should be 172.16.20.252. instead of 172.16.20.1. 

 

No need to configure the vlan on the CUCM NIC.



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Same

3be5a35c-1808-4ffc-bf8b-a64a454c0ba1.jpg

There is no need to configure the server port as trunk, it can be access port. Did  the phone received vlan information. does it shows operational vlan 105 ? 

 

Whats your default gateway for 172.16.20.0 network, is it  interface vlan  105 ?

 

Can you add below command under  interface gi1/0/45

 

Switchport voice vlan 105.

 

 

 



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As Roger mentioned I too recommend to use another dhcp server. You can make your switch as dhcp server 

 

 



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Sadav Ansari
Participant

Check your DHCP Service enabled on cm ?Configure IP-helper address command on your Vlan and set the DHCP server IP address in your case your cm working like as dhcp also .

Thanks bro but its not working.

Sadav Ansari
Participant

All the configuration looks like fine. Do one thing configured Switchport voice vlan 105 on the port where phone is connected and check on the phone network setting DHCP  is enabled and reset network setting for testing.

Roger Kallberg
VIP Advisor

The DHCP service on CM is notorious for not working good. You’d be much better of if you would use any other system to provide this service. It will save you a lot of time and effort, instead of trying to get the service to work on CM.



Response Signature


View solution in original post

Thanks Engr. Roger,

i think that kindly find screen shoot below, there is no dhcp reply,

this when i tried to connect laptop direct with be6000 server with direct vm switch with no security.

 

 

Could you please support me with DHCP option with the syntax that i have to use is to auto set VLAN and TFTP server ip on phone.

 

Regards.

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