1

NAT ports - how do they work?

view story
linux-howto

http://serverfault.com – I have the following network schema: Computer A: three nics: NIC 1 (eth0): dhcp, public internet NIC 2 (eth1): static 192.168.1.1, gateway for Computer B NIC 3 (eth2): static 192.168.2.1, gateway for Computer C Computer B: static 192.168.1.2, using gateway 192.168.1.1 (NIC 2). Computer C: static 192.168.2.2, using gateway 192.168.2.1 (NIC 3). So I applied this to get NAT working: iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE Every computer can connect to the internet now. I have been applying rules to the main computer (Computer A), like dropping connections to (HowTos)

dayu's picture
Submitted by dayu on 10/29/2012

Stories similar to NAT ports - how do they work?

I am building a small office network with virtual machines. My schema is this:

Computer A: gateway, ip 1.1.1.1, iptables used for NAT [eth0=public internet dhcp, dhcp; eth1=gateway] Computer B: client, ip 1.1.1.2, using gateway from Computer A.

NAT is working, and Computer B can access the internet using the A's gateway.

I am creating a NAT with iptables:

Computer A: eth0 (dhcp) + eth1 (static ip 192.168.0.1 - gateway) Computer B: eth1 (static ip 192.168.0.2, using Computer A as gateway)

I know how to block ICMP outgoing requests (-A OUTPUT -p icmp --icmp-type echo-request -j DROP), but that would block ICMP requests from Computer A, but not from Computer B (in fact, only for Computer A - Computer B can keep doi

Ubuntu as Internet Gateway 11 weeks 9 hours ago

I am trying to build a Computer to act as a internet gateway I installed Ubuntu desktop with two NIC cards installed.

a newbie network administrator here... I have a PC, I want to use it as transparent proxy server and also running one virtual machine as MySQL server.

I'm using 3 network cards:

eth0 is used to connect the server to my router (WAN) (IP 192.168.0.2) eth1 is used as gateway to share internet connection to my network (IP 192.168.1.1)

Can I use eth2 (192.168.1.2) as bridged NIC to my virtual mach

I have three profiles set up in /etc/network.d/ on a laptop that I'm trying to use to bridge a stand-alone computer to my main LAN in another part of the house.1. eth0 - with a static address, no gateway or dns2. wireless - with a static address, no GW or DNS3.

Wan on eth1 and Lan on eth0 28 weeks 3 days ago

I have a local network on dev eth0 Server has static IP of 10.0.0.1 Gateway is 10.0.0.1 and Dns is 10.0.0.1

I am using this network for imaging 500 plus computer...

Now, Issue that I am having is that I need to update packages and I dont want to change the configuration on eth0 because I dont want something breaking out on my imaging system... the server has two nics and I want to use eth1 to

Previously had 2 Ubuntu computers setup

Computer A (192.168.1.101) <=> Computer B (192.168.1.100) -> Internet

Computer B was the gateway, and it is dual boot, one drive Ubuntu, one drive XP. I'm using XP as the gateway now, but Computer A is extremely slow, virtually nothing getting through.

Have checked sysytem logs, verified /etc/hosts file, and all the network side of things.

hi guys, a newbie network administrator here... i have a PC, I want to use it as transparent proxy server and also running one virtual machine as MySQL server, I'm using 3 network cards,

eth0 is used to connect the server to my router (WAN) (IP 192.168.0.2) eth1 is used as gateway to share internet connection to my network (IP 192.168.1.1) and last can i use eth2 (192.168.1.2) as bridged NIC to

Topology:

C1 --192.168.111.0/24 -- R1 -- 172.30.0.0/24 -- Switch -- C6 |-- R2 -- 172.30.10.0/23 -- C5

I am a newbie in networking and I have a question about routing through subnets.

I want to ping computer C5 from computer C1 (see below).