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PPTP VPN and UDP Broadcasts

Hi all,

I am required to setup a private CS game server behind a cisco 877 router. I've set up the router to accept PPTP VPN connections (least overhead) and things seem to work fine apart from the fact that I cannot seem to be able to forward UDP broadcast packets.

In order for the/any game to be able to find any running game servers using the built in game browser it needs to be able to get UDP broadcast packets. Therefore I need to forward any UDP broadcasts through the VPN to the remote VPN clients but I haven't been able to do so successfully.

Everything else seems to work fine as the remote users are

a)able to ping all the clients in the internal network behind the router plus

b)they can access the file server too via the internal ip.

c)they can connect to the game server if they supply the IP of the server directly

However, this is not an acceptable solution as this is only a test server and I'm also required to setup other game servers and some of these games don't have a console that you can supply an IP to connect as a player can only do so using the game's built-in LAN game browser.

The internal lan is

The router has an internal-ip (VLAN1)

The VPN clients get addresses from -

Virtual-Template 1 binds to VLAN1 interface.

I've tried supplying the the ip helper-address command both under the VLAN 1 and the virtual-template 1 interfaces but I didn't get any results.

Any suggestions or advice as what to try next or how to debug this issue?

Any help is greatly appreciated

Here's my config:


! NVRAM config last updated at 14:04:39 Athens Sat Oct 10 2009


version 12.4

no service pad

service timestamps debug datetime msec

service timestamps log datetime msec


hostname Router





enable secret 5 xxxx


no aaa new-model

ip cef



no ip dhcp use vrf connected

ip dhcp binding cleanup interval 200

ip dhcp excluded-address


ip dhcp pool lan

import all





multilink bundle-name authenticated

vpdn enable


vpdn-group 1

! Default PPTP VPDN group


protocol pptp

virtual-template 1



username xxxx privilege 15 secret 5 xxxxxx


interface ATM0

no ip address

no atm ilmi-keepalive

dsl operating-mode auto


interface ATM0.1 point-to-point

no snmp trap link-status

pvc 8/35

pppoe-client dial-pool-number 1



interface FastEthernet0


interface FastEthernet1


interface FastEthernet2


interface FastEthernet3


interface Virtual-Template1

ip unnumbered Vlan1

peer default ip address pool PPTP-Pool

no keepalive

ppp encrypt mppe 128

ppp authentication ms-chap ms-chap-v2


interface Vlan1

description Internal Network

ip address

ip nat inside

ip virtual-reassembly

ip tcp adjust-mss 1452


interface Vlan14

no ip address


interface Dialer0

description External Network (ADSL)

ip address negotiated

ip mtu 1492

ip nat outside

ip virtual-reassembly

encapsulation ppp

dialer pool 1

dialer-group 1

ppp authentication chap pap callin

ppp chap hostname xxxxxxxxxx

ppp chap password 0 xxxxxxxxxxx

ppp pap sent-username xxxxxxxxx password 0 xxxxxxxxxx

ppp ipcp dns request accept


ip local pool PPTP-Pool

ip route Dialer0



ip http authentication local

ip http secure-server

ip dns server

ip nat inside source list 1 interface Dialer0 overload


access-list 1 remark INSIDE_IF=Vlan1

access-list 1 remark SDM_ACL Category=2

access-list 1 permit

dialer-list 1 protocol ip permit