Cisco 8821

You can also enable the phone to use a static TFTP server. Such a setting is particularly useful if the phone
was recently moved from one location to another.
Phone Cannot Connect to Server
Problem
The IP addressing and routing fields may not be correctly configured.
Solution
Verify the IP addressing for the phone. If you are using DHCP, the DHCP server should provide these values.
If you have assigned a static IP address to the phone, you must enter these values manually.
When the wireless IP phone loses the RF signal (goes out of the coverage area), the phone will not release
the DHCP server unless it reaches the timeout state.
Note
Check for these problems:
•
DHCP Server: If you have assigned a static IP address to the phone, you do not need to enter a value
for the DHCP Server option. If you are using a DHCP server, and the wireless IP phone gets a response
from the DHCP server, the information is automatically configured. See Troubleshooting Switch Port
Problems, available at this URL: http://www.cisco.com/en/US/products/hw/switches/ps708/products_
tech_note09186a008015bfd6.shtml.
•
IP Address, Subnet Mask, Primary Gateway: If you have assigned a static IP address to the phone, you
must configure settings for these options. See Manually Set Up the Phone Network from the Settings
Menu , on page 65.
If you are using DHCP, check the IP addresses distributed by your DHCP server. Be aware of DHCP conflicts
and duplicate IP addresses. See Understanding and Troubleshooting DHCP in Catalyst Switch or Enterprise
Networks, available at this URL: http://www.cisco.com/en/US/tech/tk648/tk361/technologies_tech_
note09186a00800f0804.shtml.
Phone Cannot Connect with DNS
Problem
The phone has incorrect DNS server information.
Solution
If you are using DNS to refer to Cisco Unified Communications Manager, you must ensure that you have
specified a DNS server. You should also verify that there is a CNAME entry in the DNS server for the Cisco
Unified Communications Manager system.
You must also ensure that DNS is configured to do reverse look-ups. The default setting on Windows 2000
is to perform forward-only look-ups.
For information about determining and changing DNS settings, see Manually Set Up the Phone Network from
the Settings Menu , on page 65.
Cisco Wireless IP Phone 8821 and 8821-EX Administration Guide for Cisco Unified Communications Manager
117
Troubleshooting
Phone Does Not Register with Cisco Unified Communications Manager