[cisco-voip] Cisco 827 adsl + ipsec voip issues

[Juan Pablo Feria Gomez]

Hi, all I have a Cisco 827 with:

ADSL Port
Ethernet
Crypto Support
Nat

x.x.x.x-----|ROUTER827|--y.y.y.y (dsl)-------internet------|ROUTER|...z.z.z.z


I have an ipsec link to communicate x.x.x.x and z.z.z.z nets, its
working fine, when i set up a voip call from z.z.z.z to the 827 router
(the pot points to the x.x.x.x ip on the router)  the 827 router tries
to answer the call through the dialer interface (the piblic ad sl link
y.y.y.y) and cant reach the z.z.z.z network...

Are there a way to force a voip pot to make the connections from the
ip of the ethernet interface as the source address to find the remote
ip through  the vpn?

Thanks in advance