View source for IP Forwarding and iptables configuration


'''Forwarding must be enabled'''<br>
root@raspbx:~# cat /proc/sys/net/ipv4/ip_forward<br>
0<br>
root@raspbx:~# sysctl -w net.ipv4.ip_forward=1<br>
net.ipv4.ip_forward = 1<br>
root@raspbx:~# cat /proc/sys/net/ipv4/ip_forward<br>
1<br>
root@raspbx:~#<br>
'''Routing and Masquerading'''<br>
iptables --table nat --append POSTROUTING -o ppp0 -j MASQUERADE<br>
iptables --append FORWARD -i eth0  -j ACCEPT<br>
<br>

'''Forwarding traffic from one port to another machine and port''' <br>

iptables -t nat -A PREROUTING -p tcp --dport 1111 -j DNAT --to-destination 2.2.2.2:1111<br>
iptables -t nat -A PREROUTING -p tcp --dport 3723 -j DNAT --to-destination 10.0.0.100:3389<br>

and finally, we ask IPtables to masquerade:<br>

iptables -t nat -A POSTROUTING -j MASQUERADE <br>

'''To delete an entry from the nat table''' <br>

iptables -t nat -L -n --line-numbers<br

and find the line that matches the rules you want to deletes.<br>
then

iptables -t nat -D <br>

Reference - http://unix.stackexchange.com/questions/205867/viewing-all-iptables-rules<br>
<source lang="text">
To get a complete presentation of the netfilter rules, you need

iptables -vL -t filter
iptables -vL -t nat
iptables -vL -t mangle
iptables -vL -t raw
iptables -vL -t security
</source>
iptables --table nat --list or in the short form: <br>
iptables -t nat -L<br>