How do I configuring Linux as a router

rcmonroig · 10-15-2014, 04:18 AM

I am trying to configure a Linux router

I am running Centos 6.5 on an i5 quadcore server with 32G of RAM and 80G hard drive

I have 2 NICs eth0 and eth1

eth0 is connected to the internal LAN with a static IP 192.168.0.1/24 with port forwarding turned on.

and eth1 is connected to our public switch with a static IP 140.x.x.127.

I have an internal VMware cloud at 192.168.0.101:9443
I configured the firewall through the GUI. I turned on ports 21 for ssh, 80 for http, 8080 for webcache and 443 for https.

I have masquerading turned on for eth1.

and packet forwarding turned on from eth0 192.168.0.1 to eth1 140.x.x.127

My question is:
how do I configure eth1 140.x.x.127 to redirect packets coming in on 8080 to 192.168.0.101:9443 in the firewall GUI?

Any help would be greatly appreciated.

Thanks,
RonM

linosaurusroot · 10-15-2014, 06:13 AM

Quote:

I turned on ports 21 for ssh, 80 for http, 8080 for webcache and 443 for https.

ssh is 22

Show "cat /proc/sys/net/ipv4/ip_forward".
Show your "iptables-save" output (with IPs redacted 140.x.x.12 if you wish).

rcmonroig · 10-15-2014, 11:56 AM

Thanks for your quick response. I'm attaching a copy of the iptables and result of ip_forward setting. I appreciate you looking at this.

RonM

rcmonroig · 10-15-2014, 05:32 PM

Please refer to the attachment for a diagram of the router question.

linosaurusroot · 10-15-2014, 08:10 PM

Do these sort you out?

http://blog.softlayer.com/2011/iptab...rt-redirection

http://linux-ip.net/html/nat-dnat.html

SAbhi · 10-15-2014, 08:57 PM

well i guess a route is need to be set here to achieve you want..
see 'route' man page for more.

Code:

route add -host x.x.x.x gw x.x.x.x eth0 (something like this)

rcmonroig · 10-16-2014, 06:34 PM

I will check it out and back to you. Thanks again.

Parbold · 10-17-2014, 11:11 AM

Quote:

How do I configure eth1 140.x.x.127 to redirect packets coming in on 8080 to 192.168.0.101:9443 in the firewall GUI?

I did something similar using iptables:-

I am not an iptables expert but I think the config commands you would require are:-

Code:

# Allow portforwarding of 8080 traffic to 192.168.0.101:9443
iptables -A PREROUTING -t nat -i eth1 -p tcp --dport 8080 -j DNAT --to 192.168.0.101:9443
iptables -A FORWARD -p tcp -d 192.168.0.101 --dport 9443 -j ACCEPT
service iptables save

The you would connect to the local IP address on eth1 on port 8080, but the traffic would be sent to 192.168.0.101 port 9443