[pptp-server] PPTP

[Karan Ingale]

Hello,
 I am running Redhat Linux 6.2 on a Pentium machine. I
have applied the Kernel patch for PPTP. I am using
IPChains to filter out specific outgoing and incoming
traffic.
 I use a Windows 2000 machine from the internal
network, to make a VPN session with a server on the
internet. If I don't apply any rules for ipchains (All
Accept), I am able to make the connection. But as soon
as I apply the following rules, I am not able to make
a VPN connection with the VPN server on the internet.

This is the policy I used to deny all ports

  ipchains --policy input    DENY
  ipchains --policy output   DENY
  ipchains --policy forward  DENY

This is the policy for PPTP

  ipchains --append        input \
           --jump          ACCEPT \
           --interface     $EXTERNAL_INTERFACE \
           --source        $EXTERNAL_NETWORK $PPTP \
           --destination   $LOCALHOST $UNPRIVPORTS \
           --protocol      tcp  
#           --protocol      tcp  ! -y    #SYN BIT
Check

  ipchains --append        output \
           --jump          ACCEPT \
           --interface     $EXTERNAL_INTERFACE \
           --source        $LOCALHOST $UNPRIVPORTS \
           --destination   $EXTERNAL_NETWORK $PPTP \
           --protocol      tcp

  ipchains --append        input \
           --jump          ACCEPT \
           --interface     $EXTERNAL_INTERFACE \
           --source        $EXTERNAL_NETWORK $PPTP \
           --destination   $LOCALHOST $UNPRIVPORTS \
           --protocol      udp

  ipchains --append        output \
           --jump          ACCEPT \
           --interface     $EXTERNAL_INTERFACE \
           --source        $LOCALHOST $UNPRIVPORTS \
           --destination   $EXTERNAL_NETWORK $PPTP \
           --protocol      udp

 I have similar policies for other ports. They work
just fine. 
 Can anybody solve my problem?

Thanks.

Karan. 

Systems Engineer.
Disha Technologies.



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