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VPN with External 3G Router


i have a cisco 881 and i wonder to configure the VPN remote access.
The problem that i have not ADSL modem and i use external 3G Router.

With this Router the WAN of the Cisco 881 is a private IP.
could you please hel me who i can do this?
thanks you

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I have not done this myself

I have not done this myself so can not speak from experience. But I would think that it is possible to get this to work. You would do the regular configuration of site to site VPN on your 881. It will generate the IPSec packet with its private address as the source and at the external 3G that address will be translated. If you can determine what address the 3G is translating to you may be able to use that address when you configure the other router for its peer address. But since it is possible that the 3G might not always translate to the same address it is likely that on the other router you may need to configure a wild card for the peer.


One implication of doing this is that your 881 will always need to be the one to initiate the VPN tunnel. Since the other router will not be sure what your address will be it could respond but not initiate the tunnel.





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