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problem with PPTP authentication through a tunnel server

I'm trying to authenticate users connecting with PPTP to Radius, I configured the Cisco 3660 (NAS) for accepting these connections but I'm experiencing some problems, it authenticates correcttly but it gives me the 734 DUN error which is

Error 734 : The PPP link control protocol terminated..

i searched on the web and all I found as a fix for this error was to clear on the pptp client the Enable LCP Extentions box, but unsuccessful, the configuration of vpdn and virtual-template are in the following statements :

vpdn enable


vpdn-group 1

! Default PPTP VPDN group


protocol pptp

virtual-template 1


interface Virtual-Template1

ip unnumbered FastEthernet0/0

peer default ip address pool ipko-ippool1

no ppp lcp fast-start

ppp authentication pap ppp-radius

ppp ipcp predictive

and here are some Debugs ( debug ppp authentication and debug ppp errors)

ppp727 PPP: Using vpn set call direction

ppp727 PPP: Treating connection as a callin

ppp727 PPP: Authorization required

ppp727 PAP: I AUTH-REQ id 28 len 16 from "mesut"

ppp727 PAP: Authenticating peer mesut

ppp727 PPP: Sent PAP LOGIN Request

ppp727 PPP: Received LOGIN Response PASS

Vi3.1 PAP: O AUTH-ACK id 28 len 5

Vi3.1 IPXCP: LCP not open, discarding packet

Vi3.1 IPCP: LCP not open, discarding packet

if you need any other output from the router to identify the problem just ask me to do so

hope that you can help me



Re: problem with PPTP authentication through a tunnel server

The error "734 : The PPP link control protocol terminated" probably indicates incorrect security settings in Dial-up Networking connection. Please do this procedure at clients, go to dial up networking..

Select the XTRA connection

Click More

Select Edit entry and modem properties

Click the Security tab

Click Accept any authentication including clear text

Click OK

Hope above procedure solves your problem..

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