portfowarding question

alsharifhoussam · 01-12-2012, 06:31 AM

Hello,
I had a gateway linux, my other PC runs mailserver ,
at the local network, when I go to http://192.168.10.10 I get the login to webmail,
the gateway had public IP, I want users over Internet which go to http://PUBLICIP:3000 or any other port to be able to view this mail server.
Any help?
Thanks

TenTenths · 01-12-2012, 09:16 AM

Assuming you're using iptables then google for IPTABLES FORWARD

cbtshare · 01-12-2012, 11:08 AM

you can use this script to do it all for you ,if your using iptables:

Quote:

#!/bin/bash

echo "Enter your internal connection name first followed by your external connection name e.g: eth1 eth0"

if [ $# != 2 ]
then

INTIF="#1"

EXTIF="#2"

else

echo You need to enter two names,your internal connection name eg(etho) first then your external connection eg(eth1)

fi

/sbin/depmod -a
/sbin/modprobe ip_tables
/sbin/modprobe ip_conntrack
/sbin/modprobe ip_conntrack_ftp
/sbin/modprobe ip_conntrack_irc
/sbin/modprobe iptable_nat
/sbin/modprobe ip_nat_ftp
/sbin/modprobe ip_nat_irc

echo " Enabling IP forwarding..."
echo "1" > /proc/sys/net/ipv4/ip_forward
echo "1" > /proc/sys/net/ipv4/ip_dynaddr

echo " External interface: $EXTIF"
echo " External interface IP address is: $EXTIP"

echo " Loading proxy server rules..."
# Clearing any existing rules and setting default policy
iptables -P INPUT ACCEPT
iptables -F INPUT
iptables -P OUTPUT ACCEPT
iptables -F OUTPUT
iptables -P FORWARD DROP
iptables -F FORWARD
iptables -t nat -F

# FWD: Allow all connections OUT and only existing and related ones IN
iptables -A FORWARD -i $EXTIF -o $INTIF -m state --state ESTABLISHED,RELATED -j ACCEPT
iptables -A FORWARD -i $INTIF -o $EXTIF -j ACCEPT

# Enabling SNAT (MASQUERADE) functionality on $EXTIF
iptables -t nat -A POSTROUTING -o $EXTIF -j MASQUERADE

if [ $? -eq 0 ]
then
echo " Proxy server rule loading complete"
fi

MartinStrec · 01-12-2012, 12:11 PM

If you want to config the same as the script of user 'cbtshare' does.

Edit /etc/sysconfig/iptables
and /etc/sysconfig/ip6tables

If your IP tables have been generated, use system-config-firewall or other system rather then modify those files directly.
Also tools like system-config-firewall or system-config-firewall-tui have GUI or TUI interface to easy set up NAT.

also modify /etc/sysctl.conf
if ip_forwarding is not enable by default
net.ipv4.ip_forward = 1
...

cbtshare · 01-12-2012, 06:51 PM

[QUOTE=MartinStrec;4572967]

Quote:

also modify /etc/sysctl.conf
if ip_forwarding is not enable by default
net.ipv4.ip_forward = 1

Ahhh, yea, I edited the script to input your comment, thanks for that

new script is below:

Quote:

#!/bin/bash

if [ "$#" -eq "2" ]
then

INTIF="$1"

EXTIF="$2"

/sbin/depmod -a
/sbin/modprobe ip_tables
/sbin/modprobe ip_conntrack
/sbin/modprobe ip_conntrack_ftp
/sbin/modprobe ip_conntrack_irc
/sbin/modprobe iptable_nat
/sbin/modprobe ip_nat_ftp
/sbin/modprobe ip_nat_irc

echo " Enabling IP forwarding..."
echo "1" > /proc/sys/net/ipv4/ip_forward
echo "1" > /proc/sys/net/ipv4/ip_dynaddr
FWDIP=$(sed 's/net.ipv4.ip_forward = 0/net.ipv4.ip_forward = 1/g' < /etc/sysctl.conf>/tmp/show.txt)
cp -f /tmp/show.txt /etc/sysctl.conf
echo " External interface: $EXTIF"
echo " External interface IP address is: $EXTIP"

echo " Loading proxy server rules..."

# Clearing any existing rules and setting default policy
iptables -P INPUT ACCEPT
iptables -F INPUT
iptables -P OUTPUT ACCEPT
iptables -F OUTPUT
iptables -P FORWARD DROP
iptables -F FORWARD
iptables -t nat -F

# FWD: Allow all connections OUT and only existing and related ones IN
iptables -A FORWARD -i $EXTIF -o $INTIF -m state --state ESTABLISHED,RELATED -j ACCEPT
iptables -A FORWARD -i $INTIF -o $EXTIF -j ACCEPT

# Enabling SNAT (MASQUERADE) functionality on $EXTIF
iptables -t nat -A POSTROUTING -o $EXTIF -j MASQUERADE

if [ $? -eq 0 ]
then
echo " Proxy server rule loading complete"
fi

else

echo "You need to enter two names,your internal connection name eg(etho) first, then your external connection eg(eth1), example ./scrptname eth0 eth1

fi

Thank you