Network address translation (NAT) is an network technique that allows that a public IP can be shared by many private hosts(machines).

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What are the risks of NOT using a firewall (home computer)?

Since a password is required to be a superuser (to install and modify programs), what are the risks to not use a firewall under Ubuntu ? More particularly if I am using a NAT router ?
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5answers
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Virtualbox DNS stopped working on upgrade to 12.10

I have a Debian image setup on Virtualbox that uses the default NAT to access the internet. It was working fine before I upgraded to 12.10. After I upgraded the DNS lookups no longer work. I still can ...
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1answer
509 views

How to disable NAT for IPv6 (NAT66)?

The current Ubuntu LTS does not support NAT tables for IPv6 (i.e. there is no ip6tables -t nat), and I'm fine with that, in fact, a NAT-less environment is the "core" of my networks. But, the next ...
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930 views

How to switch between network interfaces from console?

I've installed Debian in my VirtualBox (my host OS is Ubuntu). And there I configured two network interfaces: eth0 as NAT, and eth1 as Bridge. NAT I need to have access to the internet in virtual OS, ...
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Configuring Ubuntu vmware guest NAT

I have a Windows host that runs guest Ubuntu VM via vmplayer. That virtual machine will be cloned, distributed among several people (running Windows hosts) and used for conducting a programming ...
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Configure Nat in Ubuntu 12.04

I want to configure NAT for my network of 10 computers so that the data is transmitted via a single pc. Can anyone give a good tutorial for it?
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1answer
7k views

how to connect to a remote desktop behind a router?

Here's my setup: I have a laptop that I roam around everywhere with, and I have a desktop computer at home that is connected to the web using a router with NAT. My objective here is to create an SSH ...
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1answer
4k views

sharing internet between network interfaces

I have a laptop with lubuntu 11 with two network interfaces, wireless and wired. Wireless interface connects to the router with DHCP and provides access to the internet. The wired interface has a ...
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2answers
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Using Ubuntu 14.04 as router with iptables, clients can't go online. Probably DNS issue, iptables setting needed

CORRECTION 3: SOLVED! I needed to add the the official DNS server of my departement's VLAN as DNS to the clients. I've read through a large number of posts about iptables issues when using Linux as ...
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1answer
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How to share internet access between Ubuntu and Windows guests OS in VirtualBox?

Using VirtualBox. There's two Virtual Machines, Ubuntu 10.04 and Windows 7. On Ubuntu: There's two ethernet interfaces. Bridge interface (eth0) who can access the internet. ping www.google.com ...
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How can I solve an Xbox 360 'NAT Moderate' issue if I don't have access to the router? [closed]

After finally managing to get my Xbox 360 to connect to live, I've run into the "NAT moderate" issue. First of all here's my setup... wireless broadband >(usb)> laptop ubuntu 11.10 >(ethernet)> ...
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1answer
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Networking problem with Ubuntu as guest in VMware workstation on Windows 7 64bit

I've the following configuration: A. Physical machine: Windows 7 64bit with VMWare workstation 8 with a physical network adapter with this ip configuration: IP 192.168.1.101 Subetnet Mask ...
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2answers
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vitualbox NAT stopped working after Ubuntu upgrade to 12.10

After upgrading to 12.10 from 12.04 none of my virtualbox virtual machines can use NAT to access the network. I have tried vboxmanage modifyvm --natdnsproxy1 on and/or --natdnshostresolver1 on, but ...
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1answer
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Two guest in one NAT range (virtualbox)

I have two VMs(Ubuntu) in virtualbox and I wanna assign the first one 10.0.3.15 and the other one 10.0.3.14. But when I set network type to NAT the network adresses are different, 10.0.3.15 and ...
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1answer
231 views

A question about the Internet/ConnectionSharing (NAT) via iptables

I'm following this tutorial to setup a NAT gateway: https://help.ubuntu.com/community/Internet/ConnectionSharing#Ubuntu_Internet_Gateway_Method_.28iptables.29 With simple eth0 as WAN and eth1 as LAN ...
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1answer
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NAT not working in a container

Following instructions I've installed docker on ubuntu 13.04 (and 12.04 + 3.8 kernel), pulled the base container and started a shell inside it. It got a private IP and can ping it's default gateway ...
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1answer
929 views

Unable to connect to my remote Ubuntu system using SSH

I want to connect to my remote PC running on Ubuntu 12.10 using SSH. But when I try ssh my_username@my_current_ip, I get this error: ssh: connect to host 117...** port 22: Connection timed out I ...
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0answers
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Ubuntu router breaking internet radio streams

I have Ubuntu 12.04 up and running fine as a DHCP router with great throughput to my connected devices. two single nic's (one onboard and one PCI-e, both with Realtek 8111E chips) are used as WAN and ...
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1answer
593 views

Is it possible to setup a DHCP server only for local virtual machines?

I have a quick question. I have a bunch of virtual machines (VMWare Workstation) running on an Ubuntu server and have found that VMWare NAT (DHCP) service is unreliable and slow. I have to use NAT ...
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Setting up NAT for internet access on a connected router

I'm setting up a NAT for a connected router to my laptop using the following command (IP forwarding is enabled): sudo iptables -t nat -A POSTROUTING -s 192.168.47.0/24 -o eth0 -j MASQUERADE So ...
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1answer
545 views

How can I 'ssh' to an ubuntu server running on VirutalBox

I have installed Ubuntu Server on a virtual machine in VirtualBox which runs on Windows 7. How can I connect through ssh to that virtual machine? I go and type 'ifconfig', and i get this address ...
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1answer
873 views

ufw configuration nat ppp0

please some tips how i can allow this request in ufw: [UFW BLOCK] IN=ppp0 OUT=eth0 MAC= SRC=10.11.22.2 DST=8.8.4.4 LEN=71 TOS=0x00 PREC=0x00 TTL=127 ID=52 PROTO=UDP SPT=59405 DPT=53 LEN=51 i tried ...
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iptables/netfilter: What's the difference between PREROUTING and FORWARD?

I am trying to understand how this system works and I have problems to understand the difference between using NAT PREROUTING or filter FORWARD. From what I understand, the PREROUTE can send the ...
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1answer
815 views

Hardcoded static IP assignment for eth1

I'm setting up a NAT, and need to assign a static IP to my eth1 interface. The problem is that once in a while, it resets, and I need to run the following command again: sudo ifconfig eth1 ...
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1answer
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How to make sysctl network bridge settings persist after a reboot?

I am setting up a notebook for software demo purpose. The machine has 8GB RAM, a Core i7 Intel CPU, a 128GB SSD, and runs Ubuntu 12.04 LTS 64bit. The notebook is used as a KVM host and runs a few KVM ...
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1answer
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IPv4 Address Sharing Issue? Trying to map IPv4 address from host OS to BT5 VM [closed]

I'm having a general networking issue in regards to my Backtrack 5 (x64) KDE VM in VirtualBox. The VM appears to be on a separate subnet, but for my purposes, I'd like to include the VM in the private ...
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1answer
45 views

Adding bridge for LXC breaks NAT/DNS

I am having a issue with a small home server. This server operates as a DNS/DHCP/NAT. I am also trying to add a few LXC instances with JUJU however I am running into a issue with the bridge. When I ...
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1answer
58 views

no network in ubuntu13 when virtal box is configured with bridged adpater

I am using Ubuntu 13 on virtual box with my host being Windows 8. My aim is I want to ping from host to guest or from any physical machine to guest (Ubuntu).I am able to ping from guest to host but ...
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Unable to share internet via NAT connection sharing

I've been using my Jetson TK1 Remotely via ssh and NAT connection sharing as described here. Earlier everything was working perfectly, but now whenever I try to share my internet connection by running ...
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NATing ports selection using hardware detection

I have a linux box to be used as a router with a wlan port in AP mode. The internet input to the board may come from either an eth port (WAN mode) or another wlan port. There is also VPN running that ...
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1answer
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Dnat prerouting does not work on Ubuntu 14.04

I've got a Ubuntu 14.04 server used as firewall, router, dhcp, dns and proxy. Everything works properly from inside to the internet, but the forwarding from outside to the inside network doesn't work. ...
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NAT forwarding not working

I tried to set up forwarding from eth0 to wlan0 in ubuntu: echo 1 > /proc/sys/net/ipv4/ip_forward iptables -t nat -F iptables -F iptables -t nat -A POSTROUTING -o wlan0 -j MASQUERADE iptables -A ...
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1answer
398 views

redirect traffic from 2 Ubuntu external NICs to specific internal hosts

I am having problems redirecting incoming traffic to 2 external facing interfaces on my Ubuntu 12.10 server to 2 separate internal hosts. I am able to redirect incoming traffic on my eth0 just fine to ...
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157 views

How to run openmpi on virtualbox with 3 PCs through SSH?

I have 3 PCs with Vista, running Ubuntu through Virtualbox on them. I have installed openmpi and ssh on them, they are connected via ethernet. The IP addresses are all 10.0.2.15. And I can ping with ...
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1answer
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how to access samba shares via nat?

I have setup a virtual machine in Virtual Box and installed a Samba Server. I changed the guest operating system's NIC from Bridged to NAT for a reason that I can't remember. I then added a additional ...
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1answer
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Log destination IP with iptables

I want to log destination IP addresses in my Ubuntu router. I have two network cards eth0 - 10.0.101.254 eth1 - 10.0.101.253 10.0.101.254 is the GW for all hosts on my network. The router ...
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Open source stun turn server which can do hole punch is there similar packages?

Is there any open source stun/turn server which can do hole punch like numb for Ubuntu ? Numb is a STUN/TURN server. Description A STUN/TURN server is used for NAT traversal in VoIP. ...
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Making Localhost as worldwide server

I am using Ubuntu 12.04 with KDE desktop. I have installed apache2 on my pc. I want set my localhost as remote accessible server. What I must to do? What is the NAT or Ubuntu servers settings?
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1answer
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How to setup IPTABLES for logging/monitoring usage while using a DSL with a dynamically assigned IP

I am trying to set up a system to do NAT and other iptables-stuff (like logging, firewall, monitoring, etc.). The ISP provides a dynamic IP address and the DSL modem does NAT. I have the following ...
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1answer
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Problem in virtualbox network

Install first time it was working properly. I wanted change network interface but i did't keep a backup. Now i can't connected to network in ubuntu server my host system is ubuntu pls advice me what ...
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2answers
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NATTING in Ubuntu Server

My Server has two NIC, One is connected to the Internet Service provider with dhcp ip (dynamically change) given by ISP and other NIC is connected with local Switch with 192.168.1.1 IP. Now I want to ...
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How ntopng connects to nprobe server behind NAT

I have nprobe installed and running in a machine which is behind a NAT (let us say PAT). The ntopng is located outside NAT and we know that ntopng is the client which opens ZMQ connection to nprobe ...
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Configure DHCP on Ubuntu 12.04 to share internet to subnet

I'm well aware of the plethora of documentation on setting up NAT and a DHCP server in order to share internet to a LAN. Here are a few articles that I think are getting me close, however I still ...
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Port restricted clone NAT not working

I have WIFI router contains public IP (10.10.10.10 dummy IP). But my router has no option for port restricted clone NAT, so I setup another computer (ip:192.168.1.200) installed Ubuntu, forward all ...
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How to use my ubuntu server as router?

+---+ eth1- *.1.6| S | =========| | |PC1|private net -------------------- ...
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IPtables logging… continues after command is commented and old rules flushed

I have the following iptables script. I do a sudo to execute it but before doing so I run a sudo iptables -F to flush all old rules. Yet, there are entries with prefix of iptables2: #iptables -t nat ...
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NAT to PPTP Client

I have not got much experience with routing and so we turn to you. I have a WAN interface and interface ppp0 Clients are connected via WAN to PPTP site. I would have no need to dial a VPN like to add ...
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1answer
555 views

UFW blocks traffic in NAT

I've created a VM guest with libvirt with the default NAT Bridge. (Host and Guest Ubuntu 14.04 Server) After creating allow rules for SSH and enabling ufw - on the guest - i can't connect to the ...
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Routing with virtual interfaces

How do I setup Ubuntu Server (14.04.01) with public eth0 and private eth1 to act as a router for multiple public/private IP pairs. eth0: 200.0.0.2 eth0:1: 200.0.0.3 eth1: 192.168.0.1 ...
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1answer
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Setup NAT on Ubuntu 14.04

I'm trying to insert my desktop between an appliance and the rest of the network to monitor the traffic coming off of it due to some security concerns. I'd like to setup NAT so that the devices behind ...