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

learn more… | top users | synonyms

50
votes
7answers
4k views

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 ?
23
votes
6answers
6k views

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 ...
7
votes
1answer
671 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 ...
6
votes
2answers
1k 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, ...
6
votes
2answers
51k views

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 ...
5
votes
2answers
35k views

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?
5
votes
1answer
8k 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 ...
5
votes
1answer
75 views

Accessing a LAMP webserver that's behind a Ubuntu VM acting as a firewall

I currently have two VM's set up in the following manner: /-----------------------\ /-----------------\ | Ubuntu VM | /---------------\ ...
4
votes
1answer
5k 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 ...
4
votes
1answer
9k views

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 ...
3
votes
1answer
8k views

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 ...
3
votes
2answers
1k views

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)> ...
3
votes
1answer
79 views

configure iptables to redirect traffic to a specific IP address

I have just began using iptables. I have a server with a public ip address (A.A.A.A) wich is hosting a Virtual Machine (B.B.B.B) on local network. I want to redirect all inbound traffic on the port ...
3
votes
1answer
12k views

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 ...
2
votes
2answers
5k views

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 ...
2
votes
1answer
6k views

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 ...
2
votes
1answer
431 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 ...
2
votes
1answer
2k views

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 ...
2
votes
1answer
1k 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 ...
2
votes
0answers
293 views

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 ...
2
votes
1answer
646 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 ...
1
vote
2answers
4k views

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 ...
1
vote
2answers
182 views

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 ...
1
vote
1answer
781 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 ...
1
vote
1answer
1k 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 ...
1
vote
1answer
2k 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 ...
1
vote
1answer
486 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 ...
1
vote
1answer
3k views

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 ...
1
vote
1answer
1k views

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 ...
1
vote
0answers
983 views

No Internet Access on VMs in NAT Network in VirtualBox

I have created a a NAT Network in VirtulBox 5 In Ubuntu 14.04 LTS with following settings Natework Name : NatNetwrok1 Network CIDR: 10.0.2.0/24 Support DHCP :enabled Support IPv6 :disabled without ...
1
vote
1answer
205 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 ...
1
vote
1answer
69 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 ...
1
vote
2answers
112 views

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 ...
1
vote
0answers
26 views

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 ...
1
vote
1answer
2k views

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. ...
1
vote
1answer
295 views

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 ...
1
vote
0answers
199 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 ...
1
vote
1answer
1k views

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 ...
1
vote
1answer
2k views

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 ...
0
votes
3answers
1k views

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?
0
votes
1answer
27 views

DNAT redirecting to specifc port is not working

I want to redirect ssh by port using DNAT, and i do try to ssh it through the command > username@IP_ADDRESS:10003 and i got this message "ssh: Could not resolve hostname IP_ADDRESS:10003: Name or ...
0
votes
2answers
4k views

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. ...
0
votes
1answer
53 views

How to resolve multiple hosts inside a NAT firewall

My apologies if this has been asked before, but I can't seem to find a complete solution. I have a hosted sub-domain at no-ip.com with a wildcard DNS option enabled. On my end I have a firewall ...
0
votes
1answer
170 views

NAT port forwarding using iptable doesn't work

I have a server with Ubuntu Server and a Xubuntu virtual machine on it, virtualization software is virt-manager. Ubuntu Server IP: 172.16.63.140 Xubuntu Virtual Machine IP: 192.168.122.4 I can do ...
0
votes
1answer
188 views

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 ...
0
votes
1answer
30 views

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 ...
0
votes
2answers
8k views

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 ...
0
votes
1answer
27 views

How change Gateway of subnet ( private network, Internal) on MAAS

Ubuntu : 16.04 MAAS: 2.0.0 beta 3 I need to change the gateway address of my subnet( private lAN,Internal which is 192.168.120.1) to ip address of my region/rack controller( internal ip ...
0
votes
0answers
34 views

MAAS 2.0 and Ubuntu 16.04 Node Enlist get connection error to Internet behind a NAT

OS: UBUNTU 16.04 MAAS : 2.0.0 beta 3 1 Node as region/rack controller 2 Nodes Nodes are behind proxy I defined NAT on my region/rack controller i defined proxy on MAAS GUI When nodes try to boot ...
0
votes
0answers
22 views

How can I ssh to a server after running sshuttle?

I ran sshuttle on a server to Nat all of it's traffic behind a proxy server, so in this way I can hide it's IP address. But the problem is that I can not SSH to the server, as SSH will be behind the ...