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Old 02-23-2005, 09:25 AM   #1
Registered: Oct 2004
Distribution: Debian, Ubuntu
Posts: 38

Rep: Reputation: 15
/proc/ ip forwarding etc

Running Debian sarge kernel 2.6.8. I'm using my linux box as a router for the rest of my network. I want to use NAT and forward ports to different clients.

I have a script I got from a friend. It succesfully opens/closes ports on the router itself but it won't forward anything.

This is a part of my script.

# Enable response to ping.
$ECHO "0" > /proc/sys/net/ipv4/icmp_echo_ignore_all

# Disable response to broadcasts (smurf attack).
$ECHO "1" > /proc/sys/net/ipv4/icmp_echo_ignore_broadcasts

# Don't accept source routed packets (rarely used for legit purposes).
$ECHO "0" > /proc/sys/net/ipv4/conf/all/accept_source_route

# Disable ICMP redirect acceptance (can alter routing tables).
for interface in /proc/sys/net/ipv4/conf/*/accept_redirects; do
$ECHO "0" > ${interface}

# Enable bad error message protection.
$ECHO "1" > /proc/sys/net/ipv4/icmp_ignore_bogus_error_responses

# Turn on reverse path filtering (ip spoofing).
for interface in /proc/sys/net/ipv4/conf/*/rp_filter; do
$ECHO "1" > ${interface}

# Log spoofed packets, source routed packets, redirect packets.
$ECHO "1" > /proc/sys/net/ipv4/conf/all/log_martians

# Make sure that IP forwarding is turned off. We only want this for a multi-homed host.
$ECHO "0" > /proc/sys/net/ipv4/ip_forward

All these files don't exist. What did I miss? Probably something in the kernel.
Old 02-23-2005, 03:44 PM   #2
LQ Newbie
Registered: Dec 2003
Location: Germany
Distribution: Gentoo
Posts: 27

Rep: Reputation: 15
as I understand you right, you want to forward some connections to a internal server like to forward everthing arriving on port 80 at your router to an internal webserver ?!? The settings you posted are responsible for the router itself, if it forwards broadcasts and pings ... . To do NAT, you have to install iptables (www.netfilter.og). This allows you to NAT and forward connections. You also have to compile your kernel with this settings.
Would be helpful to give us more information what you want o forward/NAT (ports, connections ..)!
Old 02-24-2005, 11:21 AM   #3
Registered: Oct 2004
Distribution: Debian, Ubuntu
Posts: 38

Original Poster
Rep: Reputation: 15
No you got me all wong. I have iptables and a working script. Its just that dont have the /proc/sys folder at all. I have compiled sysfs into the kernel but to no avail.
Old 02-24-2005, 11:34 AM   #4
Registered: Aug 2002
Posts: 117

Rep: Reputation: 15
Sounds like the kernel does'nt have the options compiled in. Make sure both CONFIG_PROC, CONFIG_SYSCTL are enabled, and built directly into the kernel.
Old 02-24-2005, 11:58 AM   #5
Registered: Oct 2004
Distribution: Debian, Ubuntu
Posts: 38

Original Poster
Rep: Reputation: 15
Yes they are!

I have /proc with different stuff in it but not /proc/sys

EDIT: oops, I don't have SYSCTL. Thought of SYSFS

Last edited by Ossar; 02-24-2005 at 12:00 PM.


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