Problem PPTP through router 1811

[patgeo1984]

hi guys,

I turn to you for help about vpn passthrough through a router

cisco 1811. The problem is this we have users that connect to WLANs

through router 1811 that goes to internet through a DSL connection. the problem is

that we can connect to the office to customer VPNs configured with IPSEC, but we can not make VPN to clients with

PPTP.

user lan> 1811 router> dsl> customer IPSEC vpn OK

user lan> 1811 router> dsl> customer PPTP vpn  Fail

In advance
thank you very much

[patgeo1984]

someone has experince with this problem??

[Jay Young]

Patgeo1984,

The issue revolves around PPTP's use of protocols and how they differ from IPsec.

PPTP uses GRE for the transport of data across the internet.  Since GRE has no port numbers many PAT/NAT devices find it difficult to do the address rewrites correctly.  IPsec has a function to encapsulate the ESP packet within another GRE packet, this way it is very easy for those intermediate devices to handle the translation.

Perhaps you can look at this document which explains how to get it working in IOS.

http://www.cisco.com/en/US/tech/tk827/tk369/technologies_configuration_example09186a00800949c0.shtml

-Jay