Subject: Protocol GRE(47)-packets are blocked from outside

From: "hm" <[email-masked]>
Date: Sat, 5 Jul 2003 14:59:55 +0200

Hi,

I've the problem, that my configuration did block the GRE protocol when I
try to connect to a pptp server from my net (the returning packets). I've
sniffed
and I saw that icmp-packets with protocol unreachable went back to the
server.
The same thing for protocol icmp did work. I'm using also the modules from
netfilter for pptp and gre, but also without them the problem occurs...
I have my configuration attached...thanx ahead...

Flushing all current rules: - OK
Removing user defined chains: - OK
Changing target policies to DROP:  - OK
Allowing 192.168.1.0/24 traffic out: - OK
Allowing 192.168.7.0/24 traffic out: - OK
Allowing 217.88.183.59/32 traffic out: - OK
Allowing response traffic: - OK
Allowing localhost communications: - OK
Allowing connections to udp port 4672: - OK
Allowing connections to tcp port 22: - OK
Allowing connections to tcp port 80: - OK
Allowing connections to tcp port 443: - OK
Allowing connections to tcp port 4662: - OK
Allowing connections to tcp port 1720: - OK
Allowing connections to tcp port 1723: - OK
Forwarding 217.88.183.59(4662) to 192.168.1.3(4662): - OK
Forwarding 217.88.183.59(4672) to 192.168.1.3(4672): - OK
Forwarding 217.88.183.59(1720) to 192.168.1.2(1720): - OK
Masq'ing 192.168.1.0/24: - OK
Masq'ing 192.168.7.0/24: - OK
Masq'ing 217.88.183.59/32: - OK
Allowing Gateway out eth1 - OK
Allowing Gateway to connect to self - OK
Allowing protocol 1 connections from 0/0: - OK
Allowing protocol 47 connections from 0/0: - OK
Enabling dropped packet logging: - OK