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AseemAnand
Beginner

Cisco 7942/62 IP phones not registering

Hi Team,

 

I have around 10-12 IP phones (7962) which are not registering with CUCM 11.5. The phones were previously registered but there was a WAN change during which the phones got reset.

 

The same site has got 7962 IP Phones which are working fine. 

 

I found something strange, the IP phone gets list of 4 DNS servers from DHCP. One of the 4 DNS server is not able to resolve the FQDN of the CUCM whereas the others DNS servers are giving a successful response in the pcap. 

 

1217 1379.134963090 10.227.105.87 10.110.249.22 DNS 101 Standard query 0x000e A abcxxxxx.xxx.xxx.xxxx.com.au

1218 1383.134680520 10.227.105.87 10.110.249.22 DNS 101 Standard query 0x000e A abcxxxxx.xxx.xxx.xxxx.com.au

 

 

The console logs & status messages show "DNS timeout"

 

8642: WRN 02:55:54.904162 JVM: Startup Module Loader|NetUtil.traceIPv4DNSErrors:? - IPv4 DNS Timeout abcxxxxx.xxx.xxx.xxxx.com.au
8643: ERR 02:55:54.906367 JVM: Startup Module Loader|cip.sec.TvsProperty:? - Failed to resolve Tvs Ipv4 Address with hostname abcxxxxx.xxx.xxx.xxxx.com.au
 
I will get the DHCP scope changed to exclude the DNS which is not responding. 
 
Response from a working DNS:
 
1211 1351.076557230 10.56.36.139 10.227.105.87 DNS 117 Standard query response 0x000d A abcxxxxx.xxx.xxx.xxxx.com.au A 10.12.2.9
 
8 20.002251910 10.52.36.102 10.227.105.87 DNS 117 Standard query response 0x0043 A abcxxxxx.xxx.xxx.xxxx.com.au  A 10.12.2.9
 
Has somebody tested this or have encountered this before?
 
Also, not quite sure why the ip phone would be sending the request on port 2443 (yes, it is a secure phone) for TFTP node which doesn't have the CUCM service running & is not there in CCM group:
 
1055 1107.072186380 10.227.105.87 10.17.2.13 TCP 64 51476 → 2443 [SYN] Seq=0 Win=8192 Len=0 MSS=1340
1056 1107.625829320 10.227.105.87 10.17.2.13 TCP 64 [TCP Retransmission] 51476 → 2443 [SYN] Seq=0 Win=8192 Len=0 MSS=1340
 
Thanks

 

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