IP Phones Did Not Register After Power Outage

[Will Castle]

We encountered a power outage and around 20% of the Cisco IP 7841 phones did not register automatically. Is there any thing can be done to fix this issue? Attached is photos of the network settings on one of the affected phones.

[Maren Mahoney]

First, have you reset the phones manually and if so did they register? They should re-register automatically but can sometimes get stuck.

Second, the 'verify network connection' might indicate that the switch the phones are connected to are having an issue. Is it possible that settings like port VLAN or a DHCP pool for a specific VLAN were in running-config but not in startup-config?

What do the "Status Messages" on the phone read?

Maren

[Will Castle]

Thanks for responding Maren. Resetting the phones manually was my very first step and they did not registered. It defaulted back to the "verify network connection" screen. I had my network guy check the switchports and do a comparison with a switchport that has a registered phone against an affected phone. He stated all readings were identical.

Didn't think to check the status message. Unfortunately, all the affected phones are not close by.

Let me add, we just had the Cisco CM 14 installed in July, so I'm still learning the system through google and youtube videos.

[Maren Mahoney]

Do you by chance have "Web Access" enabled on the phones? If so, you can use a web browser to go to "http://<ip.of.phone>" to see the status messages and download logs.

Other than that, walking a local user through how to access the messages (someone had to send a screen-shot, eh?) and tell you what they read is the other thing you can do.

Maren

[Will Castle]

I thought I had web access enabled, but not sure...besides, I'm not able to get the IP address of the un-registered phone since it's offline now. I'm about to make my way to a location of an affected phone and get the status messages. Standby.

[Will Castle]

This is what was displaying under status.

  

[Maren Mahoney]

The operational VLAN status show that the phone learned that the voice vlan is 160. Is this your voice vlan?

The other screen shot shows the underlying problem, though, which is that the phone cannot connect to DHCP. Which means that it has the wrong VLAN or that it can't obtain an IP address on VLAN 160. That is your next investigation.

Maren

[Will Castle]

160 is the correct VLAN. 

I'm not a network guy so I'm not well verse when it comes to configuring IPs and what nots. I'm picking it up as I go along.

Attached is the status of a registered phone, in another building...and yes...the VLAN is correct.

[Maren Mahoney]

What you need to investigate is why the phone can't "acquire an IP address". Can the phone reach the DHCP server? Is the DHCP pool exhausted (due to the outage and caching)? Did an ip helper-address or dhcp-relay command go missing on one of the systems because of the outage? Are the phones that are not working scattered or all on one switch or behind one router?

This is now a networking issue and you may have to work with your network team to do a packet capture or other diagnostic work to determine why the phone can't get an ip address.

I should mention, too, that phones can be stubborn and will use a 'last known good' if they fail to get good information at boot. It might be interesting to reboot one of the phones that is working to see if a reset puts it in the same state as the ones that are not working. I've seen stranger things.

Maren

[Nithin Eluvathingal]

The registered  phone show operational vlan 1260 and you says 160 is the correct vlan.

Who is your DHCP server, is this reachable from network ?  Does the scope has IP's remaining ? You alone cannot resolve the issues. network team support is required as this device is not getting IP address from your DHCP.

[Nithin Eluvathingal]

First You must check the switch port configurations .

Your phones  have no  IP's , this could be due to below reasons.

- Unsaved switch  port configurations,  got removed during the power outage

- DHCP server is not reachable from network after Power failure

[Will Castle]

Thanks for responding Nithin.

I had my network guy check the switchports and do a comparison with a switchport that has a registered phone against an affected phone. He stated all readings were identical...on the same switch. I even deleted one affected phone from the system, added it back, and got the same results.

Let me add, we just had the Cisco CM 14 installed in July, so I'm still learning the system through google and youtube videos.

[Maren Mahoney]

Good catch @Nithin Eluvathingal ! The first screenshot posted showed a VLAN of 160, but the newer one is 1260. 

[Will Castle]

I should have mentioned this in an earlier post, but our base is sectioned off into regions and the vlan in my region is 1260 (registered phone) and the affected phone is sitting in a region that uses vlan 160.  We have several regions and the un-registered issue is spread out within the regions, not just in a specific region. 

I've came to the same conclusion as well that this is now a network issue and beyond my scope of expertise. I've been passing on the info I'm receiving to my network guys for them to troubleshoot. 

[Nithin Eluvathingal]

The phones are not getting IP, this is an issues which must be checked from network level. Either this could be a problem of DHCP server. The server might be not reachable, or the scope might be full.. or some device might have taken the same IP.

DO a reset network settings and see if this make any change. Else network team must find out why your phones in vlan 160 doesn't get IP.