Answers to: Connect via SSH/Samba from 1 box to a hidden box (NAT/PAT?) setup?

Answer by pbz

pbz — Wed, 13 Apr 2011 09:11:52 -0400

Your host B is known as a dual homed host. You need for B to route traffic between subnets 192.168.0 and 192.168.109 Configure C (and any other hosts on 192.168.0 subnet) to use 192.168.0.1 as default gateway. Configure B to use the switch as default gateway (probably already is) Configure B to route subnet 192.168.0 traffic out 192.168.0.1 Configure your switch to route subnet 192.168.0 traffic to 192.168.109.15 That will make subnet 192.168.0 accessible to all routable traffic.

You can then use firewall features in the switch and/or in B to obtain the security restrictions you want.

Answer by Kevin M

Kevin M — Thu, 29 Apr 2010 17:22:27 -0400

What you have termed PAT would work. You will need to have iptables running(or some customizable firewall). Then run the following commands:

iptables -t nat -A PREROUTING -p tcp --dport 22 -p DNAT --to-destination 192.168.0.2
iptables -t nat -A PREROUTING -p tcp --dport 135:139 -p DNAT --to-destination 192.168.0.2
iptables -t nat -A PREROUTING -p tcp --dport 445 -p DNAT --to-destination 192.168.0.2
service iptables save
echo 1 > /proc/sys/net/ipv4/ip_forward

In the file /etc/sysctl.conf, change the line:

net.ipv4.ip_forward = 0

net.ipv4.ip_forward = 1