ASA 5505 Phone Proxy NAT

Unanswered Question
Jan 13th, 2009
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Hi this is a new installation, we are configuring the ASA with Phone

Proxy features.

We already used the old Phone Proxy appliance.

The Phone Proxy feature is working, but it looks like it is proxying only the UDP

streaming, while it is not proxying the TFTP and the SCCP protocol. The external phone is

registering itself with its own external IP address, while with the previous appliance the

external phones were registering with the Phone proxy internal IP address.

This is now causing an issue because the ASA will be used only for the Proxy features,

while the customer already have his firewall infrastructure for the Internet access. So

any Internet IP address is routed back through the main firewall instead of through the


We have used the following document for the configuration


we are wondering if there is some other document that shows any other type of

configuration that can fix this issue.

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redrobish Mon, 01/26/2009 - 18:56
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perhaps a "debug phone-proxy tftp" would help you troubleshoot it.

try this link:

for common troubleshooting:

note: you might need cisco login to access these links.

hope that helps!



davidjani Tue, 01/27/2009 - 02:11
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Thanks for the response but Cisco have informed us that they have changed the way it works and what we are trying to do is no longer possible with the new style proxy. :(

Thanks Anyway.


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