Cisco Systems Configuring Linksys Routers with UDP Port Forwarding for the Phone Proxy

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Cisco ASA 5500 Series Configuration Guide using ASDM
Chapter52 Configuring the Cisco Phone Proxy
Configuring the Phone Proxy
Step5 (Optional) In the Port field, specify the port the TFTP server is listening in on for the TFTP requests.
This should be configured if it is not the default TFTP port 69.
Step6 In the Interface field, specify the interface on which the TFTP server resides. The TFTP server must
reside on the same interface as the Cisco Unified Call Manager (CUCM).
Step7 Click OK to apply the settings.
Configuring Linksys Routers with UDP Port Forwarding for the Phone Proxy
When IP phones are behind a NAT-capable router, the router can be configured to forward the UDP ports
to the IP address of the IP phone. Specifically, configure the router for UDP port forwarding when an IP
phone is failing during TFTP requests and the failure is due to the router dropping incoming TFTP data
packets. Configure the router to enable UDP port forwarding on port 69 to the IP phone.
As an alternative of explicit UDP forwarding, some Cable/DSL routers require you to designate the IP
phone as a DMZ host. For Cable/DSL routers, this host is a special host that receives all incoming
connections from the public network.
When configuring the phone proxy, there is no functional difference between an IP phone that has UDP
ports explicitly forwarded or an IP phone designated as a DMZ host. The choice is entirely dependent
upon the capabilities and preference of the end user.
Configuring Your Router
Your firewall/router needs to be configured to forward a range of UDP ports to the IP phone. This will
allow the IP phone to receive audio when you make/receive calls.
Note Different Cable/DSL routers have different procedures for this configuration. Furthermore most
NAT-capable routers will only allow a given port range to be forwarded to a single IP address
The configuration of each brand/model of firewall/router is different, but the task is the same. For
specific instructions for your brand and model of router, please contact the manufacturer’s website.
Linksys Routers
Step1 From your web browser, connect to the router administrative web page. For Linksys, this is typically
something like http://192.168.1.1.
Step2 Click Applications & Gaming or the Port Forwarding tab (whichever is present on your router).
Step3 Locate the table containing the port forwarding data and add an entry containing the following values:
Step4 Click Save Settings. Port forwarding is configured.
Table52-2 Port Forwarding Values to Add to Router
Application Start End Protocol IP Address Enabled
IP phone 1024 65535 UDP Phone IP address Checked
TFTP 69 69 UDP Phone IP address Checked