[nsp] dialup VPN;dialup site with central CallManager

[Ahmer Ghazi]

Hi All,
 
One of my clients have a dialup VPN setup with Cisco VPN Concentrator on the central side and Cisco VPN client software on Linux machines on the remote sites (about 100 of them currently, but will increase to 500) that dials into the central site through the ISP (making IP Sec tunnels).  Currently only that single Linux machine talks to the central site, and the rest of the machines on the LAN on all the remote sites do not access the corporate network.  I need to find a cost effective way of letting the IP devices on the LANs (behind the dialing Linux machines) at each site access the corporate network.  We don't have any broadband access (DSL, Cable) at the remote sites, so my understanding is that I can't use VPN 3002 HW client or PIX 501 type of devices, please correct my if I'm wrong; I'm looking for the possible options.
 
Once I achieve the above connectivity I would like to put couple of Cisco IP Phones on all the remote sites with the Call Manager on the central site.  Is there any issue with this setup (IP phones at a dial up site, registering with the Central site Call Manager).
 
I would highly appreciate your recommendations.
 
Regards,
Ahmer Ghazi