[vpn] VPN and backup access

[Franco Sabaris, Javier]

> Hi!
> 
> I'm trying to build a low cost hardware VPN, designed for very small
> branch
> offices. I want it to be reliable and flexible. I will be using broadband
> acceses: ADSL and cable will be working together in the same VPN,
> depending
> on the availability.
> 
> As VPN box, I find Netscreen is very convenient, specially the smallest
> device, the 5xp. I have tested it and it works ok.
> 
> Now I would like to improve the VPN by adding a backup access in each
> branch
> office. A ISDN dial-up access to the Internet would be great. Up to now, I
> can do that manually, if I configure the Netscreen to work with a
> dinamically assigned IP:
> 
> - Main access is a cable access
> - Backup access is an ISDN access with an ISDN router configured with
> static
> NAT, acting as DHCP server for the Netscreen device.
> 
> In case of faliure of the broadband access, I manually take the Ethernet
> cable from the broadband modem, and plug it in the ISDN router. The
> Netscreen gets the new (private but statically NATted) IP and sets up the
> tunnel again.
> 
> I would like to have a system that performs this task automatically. Since
> the Netscreen doesn't have a ISDN interface, the chances are:
> 
> a) A new VPN box that already has an ISDN interface (I've seen Netopia
> routers).
> b) Another box, that would be placed between the Netscreen and the
> broadband
> modem. That box would have two Ethernet interfaces, and one ISDN
> interface.
> In case of comunication faliure through the extern LAN interface, it would
> use the dial-up interface to gain access to the Internet; when the
> broadband
> connectivity is restored, it would have to close the dial-up connection.
> 
> Does anybody know about boxes like a) and b)? Do they work properly?
> 
> 
> Saúdos,
> Xavo
> 
> 
> 
> 
> 
> 
> 

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