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Why can I reach a different interface's IP address?

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http://unix.stackexchange.com – I'm wondering about this, and I can't seem to find an explanation on the internet. I have a linux gateway which has multiple interfaces: eth0: external ip eth1: 172.16.1.1/24 eth2: 172.16.2.1/24 ip_forward is enabled. IPtables is configured to NAT traffic from eth1 -> eth0 and eth2 -> eth0. But configured not to FORWARD traffic between eth1 <-> eth2. My question is: Why is it possible for a computer on the 172.16.2.0/24 subnet to ping 172.16.1.1 (ip address of eth1 interface)? nat Chain PREROUTING (policy ACCEPT 647K packets, 52M bytes) pkts bytes target prot opt in (HowTos)

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Submitted by Danial on 01/12/2013 – Made popular on 01/12/2013

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Scenario:

eth0 = LAN eth1 = Internet eth2 = Internet

I would like to force all traffic from eth0 between ports 1-443 through eth1 and the rest on eth2.

I am trying to recreate this behaviour using iptables under ubuntu :

Let's say we have 3 interfaces : eth0, eth1 and eth2. I must forward the traffic through a VPN interface vpn0. Then, I must assure that the incoming traffic through the VPN is redirected correctly to the right interface ( eth0, eth1 or eth2 ).

I have searched long for an answer, but didn't find anything truly usefull.

I'am trying to setup nat on RHEL4 box.

I have static ip address on eth0 and 192.168.60.1 address on privat LAN (eth1)

Also I have tap0 (192.168.168.1) interface enabled and working openvpn connection to all hosts in privat LAN (including NAT box)

I have done this numerous times before. Never the less, I have problem now and I am stuck.

Hello everyone.

First, I'm no linux expert. I know some basics of networking and windows servers mostly. And now I want to use a Linux distro (Centos 5.4) to build up a firewall for my servers on my hosting company.

What I want to / have to configure is: - A linux router - Which works on transparent routing mode (I guess its opposite to NAT mode)

Further to my earlier question about bridging different subnets - I now need to route requests for one particular IP address differently to all other traffic.

I have the following routing in my iptables on our router:

# Allow established connections, and those !not!

I need the information regarding multiple interface card.

My Scenario is:

Eth0: 172.X.X.X / X.X.X.252 GW 172.X.X.105 Eth1: 192.168.X.X / X.X.X.0 GW 192.168.1.1

My Requirement is that:

Eth0 traffic out/in gateway 172.X.X.105 Eth1 traffic in/out gateway 192.168.1.1

Mean that traffic generate from eth0 forward to its own gate way, same as eth1.

I am using the elastix server (centos) with two

ping breaks 3 years 26 weeks ago

I have implemented advance routing fo load balancing and a script for and fail over on a Linux machine which run squid and dansguardian for proxying, i have three interfaces on this machine which are

10.201.108.254 eth1 external interface connected to service provider 10.201.109.254 eth2 external interface connected to service provider

Scenario: I have one ubuntu server with two interfaces eth0 and eth1. eth0 = public ip(external ip...lets say 77.77.77.77) eth1 = intranet network(192.168.1.1)

I would like to forward all incoming traffic on port 2222 on my eth0(meaning all outside traffic that comes to 77.77.77.77) to some ip in my intranet network:192.168.1.8 on port 80.

Current firewall settings look like:

:INPUT ACCEPT

I have a server running ubuntu 10.04 with four interfaces. eth0 and eth1 have static WAN ip's, and eth2 and eth3 are connected to two separate NAT networks 192.168.0.0/24 and 192.168.1.0/24 respectively. eth0 is masqueraded and NAT traffic from eth2 is forwarded to it.