IP PHONE REGISTRATION PROBLEMS

[maccollins]

Hello,

All the IP phones in our remote office are not registering to the network. the call manager is in the head office and there's connectivity to it through a leased circuit. The IP phones are getting their correct config from the default router which is also the DHCP server for the remote site. All network devices and end devices can reach the call manager except the IP phones. The call Manager can ping the phones and when i add PC's to the voice Vlan, they can reach the call manager just fine. 

I'm suspecting the phones cant reach their default router (see symbol beside default router in the pix attached) but that's where they are getting their IP config from. I've been tearing my head out looking for a fix to no avail.

I Need help!!!!!

[R0g22]

If you look at the status messages on one of the phones, what do they say ? Are you registering these over a VPN or something ?

[maccollins]

@R0g22

Status message is that the phone has gotten an IP from the DHCP Server

The phones are registering over leased Circuit

[R0g22]

I meant status message through the phone settings. Go to Settings > and depending upon if you are using 79XX series phones, go to model information > Status Messages else if you are using 88XX, 99XX, 78XX phones, go to Status > Status Messages

[maccollins]

I'm using a 6941 IP phone and the status message under settings is

SEPA44C11D11993 get IP address from server: 10.80.42.18

[R0g22]

Can you take a pcap from one of switchports ? Enable SPAN and then hard reset the phone. Capture until the phone display stabilizes to let's say Configuring IP or Registering etc.

[maccollins]

I did that yesterday with Wireshark and the phone was just sending out broadcast for who is the default router. It kept doing that over & over again

[R0g22]

Can you share that here please ? Does the phone get a Option 150 ?

[maccollins]

Yeah sure the phone gets all the correct config from the dhcp server (default router). Option 150 is configured & works properly. I just don't know why it can't reach the default router

[maccollins]

Hello,

Find attached the capture for the IP phone. I'm at my wits end and almost tearing my hair out.

mac address of phone: a4:4c:11:d1:19:93

IP Address of phone: 10.80.42.18

on the call manger, the phones are showing unknown meaning they cant get there.

[R0g22]

Who is 10.80.42.2 ? I believe this to the default GW for the phone. Can you check the arp table on this device with a "show ip arp" ?

[maccollins]

yes 10.80.42.2 is the default router for the phones

attached is the IP arp result

[maccollins]

yes 10.80.42.2 is the default router for the phones

attached is the IP arp result

[R0g22]

The ARP entry is there on the router but from the pcap I can see that there is no response for the ARP broadcast. Have you tried rebooting the router or clearing the arp cache on the router ?

[maccollins]

Yes I have rebooted the router more than once but nothing changed