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VPN THROUGH CISCO 827/837

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supportnet2be

IS-IT--Management
May 12, 2006
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Hello i am having avery bizare problem,
i am setting up a vpn connection, as follows :


WINXP---->CISCO827ADSL---->INTERNET---->CORPORATE

i am using the windows XP VPN client to connect to my corporate server .

when i am using a normal modem (ALCATEL speedstoucvh pro etc ) i can connect without any porblems.

but when i connect my cisco router, it just dont work.
i have tried with cisco 827 ans cisco 837, it just wont work .

i started a configuration from scratch, it worked for some time, but then it just stopped, i switched my alcatel back and it worked, put cisco back again NOT WORKING.

here is my router config:

Building configuration...

Current configuration : 1166 bytes

version 12.2
no service pad
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption

hostname VPN_RTR

ip subnet-zero

ip audit notify log
ip audit po max-events 100




interface Ethernet0
ip address 192.168.1.1 255.255.255.0
ip nat inside
no ip mroute-cache
hold-queue 100 out

interface ATM0
bandwidth 1025
no ip address
no ip mroute-cache
no atm ilmi-keepalive
pvc 8/35
encapsulation aal5mux ppp dialer
dialer pool-member 1

dsl operating-mode auto
dsl power-cutback 1
hold-queue 208 in

interface Dialer0
bandwidth 1024
ip address negotiated
ip nat outside
encapsulation ppp
dialer pool 1
no cdp enable
ppp authentication chap callin
ppp chap hostname promau@tplus
ppp chap password 0 jema05

ip nat inside source list 8 interface Dialer0 overload
ip classless
ip route 0.0.0.0 0.0.0.0 Dialer0
ip http server


access-list 8 permit 192.168.1.0 0.0.0.255

scheduler max-task-time 5000
end
 
Are you statically configuring the IP information on the local PC? The previous equipment may have done the DHCP & DNS automatically were the cisco needs to be configured to do that.
 
You may want to add the following to your config as well. Other than that it should work if it is connecting to the internet.

dialer-list 1 protocol ip permit
 
It's probably a NAT traversal thing.... I assume with the Alcatel Modem your Windows XP PC is using dial-up networking and is DIRECTLY connected to your ISP and has a real IP address?

What is your Corporate Server that is terminating your VPN clients? Are you using PPTP or L2TP IPSec? If your Corporate Server is Windows 2000 and you are using L2TP IPSec then it won't work since the Dial-Up server part of Windows 2000 doesn't support NAT Traversal. This was added to the Client portion in service pack 2 but not the server part. You will need Windows Server 2003 for NAT Traversal support.


If you are trying to use PPTP then it should work, although it could be your network admins have restricted VPN connections to L2TP IPSec only.

If your Corporate VPN Servers are Windows 2003 and are behind a NAT router themselves then it could be the default behaviour of Windows XP SP2:


HTH

Andy
 
the alcatel functions same as the router ( same routing / ip etc ) so no dialup in use , vpn just going out on the LAN conenction,
i have upgraded the cisco IOS but still it is same problem...

i have tried also the MS tricks but no change... I have tested that both with cisco 827 and 837 ..

please help....
 
i have been trying to see the pptp connetions on the router and here is the outcome:

supergrp#sh ip nat trans pptp
Pro Inside global Inside local Outside local Outside global
gre 196.192.100.115:0 192.168.100.10:0 196.25.124.209:0 196.25.124.209:0
gre 196.192.100.115:32768 192.168.100.10:32768 196.25.124.209:32768 196.25.124.209:32768
gre 196.192.100.115:16384 192.168.100.10:16384 196.25.124.209:16384 196.25.124.209:16384
gre 196.192.100.115:49152 192.168.100.10:49152 196.25.124.209:49152 196.25.124.209:49152

i am out of mind here
 
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