VPN through NAT?

[Eric Anderson]

On 08/13/06 09:21, Troy Settle wrote:
> Probably not the best list to ask this on, but it's the closest that I'm 
> subscribed to...
> 
> I have several customers who use VPN (Windows PPTP) to connect to their 
> Corporate networks.  The first was sitting behind NAT on a FreeBSD 
> router.  The PPTP did not work.  I moved them out of NAT and onto a 
> regular IP, and it worked fine.  I then swapped out the FreeBSD box with 
> a Cisco 2620 and again tried the PPTP via NAT, but still it wouldn't work.
> 
> Another customer is behind a Cisco 804 and his PPTP also did not work 
> when his network was behind NAT, so I have to assign a static subnet for 
> him.
> 
>  From home, sitting behind NAT on my Netgear router, I can turn up PPTP 
> connections all day long.  What gives with FreeBSD and Cisco's 
> implementation of NAT that PPTP doesn't want to work?
> 
> Thanks,
> 


I'm no expert on the subject, but I recall hitting this in the past and 
reading about passing GRE packets through, along with a couple of ports 
to forward to the VPN endpoint.

Eric


-- 
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Eric Anderson        Sr. Systems Administrator        Centaur Technology
Anything that works is better than anything that doesn't.
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