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Connecting a remote phone to a UC540 behind ASA

We currently have a situation where the following is installed:  20+ phones (mostly SPA509Gs) via a UC540, which is behind an ASA 5505.  We also have several "remote users" that connect with IP Communicators via VPN.  We would like to add a remote office (just 2 phones, SPA 509G) to this.  But can not get the phone to register.  This remote site also has an ASA5505 with a site to site tunnel.  I can connect to the UC from the remote site and execute CUE and IOS commands.  But the phone will not register.  I suspect the problem is the way I'm setting up the phone itself.  I suspect I can not use DHCP on the phone.  Does the IP address of the phone need to match the local network or the remote network?  I have the TFTP server pointing to the same address as our IP Communicators.



Everyone's tags (4)

Connecting a remote phone to a UC540 behind ASA

Hi Chris,

Since the phones are at a remote location, they will need to use IP addressing of this remote location.

Do you have a route to the main location's VLAN100? The UC540's SCCP is binded to it's VLAN100 IP address (by default This is also the IP address you need to register to.


Ruud van Strijp


Connecting a remote phone to a UC540 behind ASA

Chris are the phone's getting the correct information from the DHCP server that they are getting IP from? you need to make sure you set the option 150 to as long as that is the address the UC that the phones on the main loctions register to. also as stated before you need to make sure all routing is posible both to the main location and from the main location to the remote site espically of the VLan of the phone network.  one last thing is if you a firwaling the tunnel you will need to excempt the phone traffic. if you have a firewall issue you could disable it in the tunnel to see if that is the issue and if so then excempt the phone traffic from being blocked.