In computer networking, network address translation (NAT) is the process of modifying network address information in datagram (IP) packet headers while in transit across a traffic routing device for the purpose of remapping one IP address space into another.

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How do I set a static IP for a virtualbox guest that has a network adapter configured for NAT?

I am running Ubuntu 12.04 as a VirtualBox guest, but I'm having trouble configuring a static IP. I have the network adapter configured for NAT, because I can't assign static IPs on my Universities ...
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40 views

Linux NATing on my own IP address

I have a question regarding Linux NAT-ing on my own IP address. Suppose I have a network interface, say eth0. It is given an IP address of 192.168.0.2. Now I apply a NAT rule in Linux saying that: ...
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336 views

Openstack seems to not map internal IPs to local network properly

I have a very confusing issue which I can't seem to resolve. I followed a guide by Loic Dachary on installing Openstack Folsom on Wheezy, and deployed it on two hosts: a cluster node, and my ...
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1answer
397 views

How can I access a server on local network using its public name?

I have a problem in which I cannot access a server using its public name from the same network as the server. Access to the server works fine from the internet. Reading up on this problem, I've ran ...
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1answer
366 views

Issue with Nginx, http authentication and dynamic IP address

I am trying to get Nginx as a reverse proxy to authenticate users performing inbound http requests. My ISP provides me with a dynamic IP. I am not sure how to configure my ADSL router (NAT rules). ...
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1answer
169 views

Can I improve speed in Hyper-V?

I use Windows Server 2008 R2 (it is host) with Hyper-V and a guest running Ubuntu 12.04 LTC. It is my settings: RAM 32768 Cores (virtual processes) 4. (I need 12) I also use virtual hard drive ...
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2answers
416 views

NAT Overloading not working, access-list not catching ips?

I have a GNS3 lab set up and I am trying to get NAT overloading working with a dynamic pool. Please see diagram The issue I am having is traffic is being routed correctly from PC1 to the ISP1 or ...
2
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2answers
403 views

Setting up NAT for multiple isolated networks with iptables

I have a gateway machine connected to multiple internal networks that I would like to set up NAT on. The catch, though, is that these networks need to be isolated from each other, which I haven't been ...
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1answer
97 views

Iptables & NAT retain original destination IP?

I've got a webfacing server that I've chopped up into guests, one of which is running apache with some pretty basic virtualhost config. I have redirection working, but my virtualhost config needs the ...
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1answer
374 views

ADSL Router - Access External IP internally

I have a problem when I'm doing an access using my DNS hosted at another server, which performs a redirect to my internal network. example: User attempting access to internal DNS: intranet.site.com: ...
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1answer
129 views

Forwarding ports from server with 2 internet connections

I have 3 interfaces on my main server, first is used for the local network, second and third are internet connections (each has its own ip routing table): eth0 192.168.0.1 eth1 9.9.9.9 eth2 7.7.7.7 ...
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3answers
2k views

NAT Gateway - Maximum connection limit

I know just enough networking to be dangerous. The nitty gritty low level details of NAT are not something I am particularly knowledgeable about. I accidentally found myself in a discussion earlier ...
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4answers
1k views

Linux - two subnets, one interface, one gateway - NAT the additional subnet

We currently have a few servers that all use the same LAN: Host1: eth0 10.0.0.1/24 Host2: eth0 10.0.0.2/24 Host3: eth0 10.0.0.3/24 Gateway: 10.0.0.254 We want to run some VMs (VirtualBox) on these ...
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0answers
34 views

making a software router for my private network [duplicate]

give me suggestion on this problem. I have 2 nic cards public ip (eth1) and private ip (eth2). now i have a linux system having centos 6.4. I made this system software router so can access internet on ...
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3answers
2k views

iptables: combine SNAT with network remapping for OpenVPN

[Apologies for the long prelude; question halfway down.] I have a working OpenVPN setup whereby a VPN server pushes a route back to one client (hereafter called the “router”) which can then expose ...
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1answer
369 views

Change IP address of incoming packet with iptables

I have a server (S1) inside LAN, where a router is outside my control. On a server openvpn is installed and I can login with ssh to it. There is another server (S2) on the LAN, and I want to forward ...
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1answer
3k views

Do you need to enable ALG features in order to NAT H323 traffic on a Juniper firewall?

Can you NAT H323 traffic if ALG features are disabled (ultimately disabled H323 traffic inspection capabilities), or is that feature required in order to NAT such traffic?
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1answer
161 views

Advanced NAT - Mix PAT with NAT

I've just configured an Ubuntu Server as a router with NAT/PAT, and I'm trying to do the following thing: I work for a school that has divided its network into smaller networks connected by routers. ...
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1answer
360 views

How to configure dns in centos to resolve internal lan ip [closed]

i have a router with nat to web server inside LAN. Also i have internal DNS server on centos. When i try to access web server from internet it works fine, but when i try to access from the LAN, DNS ...
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1answer
966 views

Windows Server 2012, Hyper-V, how to use 1 IP for all VMs? [closed]

I am running Windows Server 2012 to host several VMs. However, our ISP has only assigned us two IP addresses, one of which is assigned to the host o/s (Windows Server 2012). How can I set this up so ...
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3answers
898 views

want to Make software router having two nic cards using centos 6.4

I'm new on CentOS. I have a CentOS 6.4 system having 2 NIC cards. I want to setup a gateway so I can get internet from public ip over 1st nic card (eth1) and forward the network over 2nd nic card ...
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1answer
217 views

Enable route between subnet

I have a Centos server with three NIC cards. ETH0 Public IP xx.xx.xx.xx1/xx.xx.xx.xx2 (with two public IP) EHT1 Local Subnet 192.168.80.0 (DHCP server listening on this interface) ETH2 Local ...
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2answers
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FTP - 500 I won't open a connection to xx.xx.xx.xx

I'm running a server on AWS and I'm connecting out to a partner's FTP site (not much idea what they are running). My server has an elastic IP. In the results below xx.xx.xx.xx is the internal IP ...
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1answer
540 views

Asterisk behind a firewall

we have a bit a sticky problem on our Asterisk server, which we are struggling to resolve, I'm hoping someone with more knowledge than me can help. We are running Asterisk 1.8.23.0 on Centos 6.4 and ...
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1answer
638 views

How do I configure routing from host system to virtual machine?

I have an Ubuntu host system that is running a MAC-VLAN virtual interface on top of eth0 interface, ipv4 routing is enabled. Also, this system has a Docker (LXC) container running: docker0 Link ...
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1answer
79 views

Port forwarding to the local network machines for local network users

All machines in my network based on linux. Main server has 192.168.0.1, mail server has 192.168.0.2, client machine has 192.168.0.3 ip. I've added iptables -t nat -A PREROUTING -d 192.168.0.1 -p tcp ...
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2answers
374 views

Remote Management (VNC-style) without Port Forwarding [closed]

Is there a way of setting up a VNC-style server (RDP would do as well) on machines behind NATs, and have access to them? Should be technically possible by having outgoing connections from the NATed ...
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2answers
596 views

Web server behind NAT, how to listen for public IP address

I have a debian web server (nginx) running behind a firewall using NAT. The web server is hosting several sites that require SSL and their own IP address. I'd like to have the SSL sites listen to only ...
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1answer
237 views

Forwarding everything from external DMZ ip to NAT ip using iptables

I know there are a lot of questions about this, but I still struggling to get it working. I have a firewall which has 3 external IPs. (IPs have been changed randomly for security) eth0 Link ...
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0answers
333 views

Are my NAT rules in ASA 8.6 correct

I am working on converting some PIX rules to ASA 8.6 syntax. Do the following achieve the goal? Assumptions: outside's IP address is 66.66.66.5/29 The outside IP address I want things translated ...
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1answer
249 views

Accessing Remote Desktop on multiple windows machines behind NAT

Our company has multiple Windows servers running behind a NAT firewall. We would like to provide Remote Desktop access to these machines to our users. One of the solutions is by port forwarding. We ...
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1answer
692 views

Use External DNS Record local with additional subdomains

We have a server in our LAN which is locally available at a fixed ip. We now have a DDNS Service and a port forwarding rule to make the server available from outside. Additional we added subdomain at ...
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1answer
36 views

routing behaviour (PAT/NAT)

|(eth0: 84.23.13.43) +--------------+ | | | NAT router | ...
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3answers
8k views

Setting up VMWare ESXi 5 with a single physical NIC

I have a cheap but powerful dedicated server I am leasing with OVH, because they were recently having a promotion. I would like to try and manage all this power by playing with VMs using ESXi. ...
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1answer
185 views

EC2 VPC without NAT?

Is it possible to have an EC2 VPC with a public subnet and a private subnet, but without having to have a NAT box? The servers on the private network would not need to talk to the outside world, just ...
2
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1answer
856 views

Sharing an internet connection from a virtual Windows 2012 AD Server

I have a virtual HyperV network used by a number of virtual development and testing servers and an all-in-one Domain, DNS, DHCP server; I want to keep the many virtual servers separated from our main ...
3
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2answers
991 views

Symmetric NAT and UDP Hole Punching

I've read this question, but the explanation of Symmetric NAT wasn't detailed enough. Please could someone help me to understand the following paragraphs? I read this about Symmetric NAT: Each ...
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0answers
110 views

Routing static IPs

This is probably a simple question for you experts. I have a BT infinity business broadband account, that offers 5 static IP addresses. I'm trying to expose a server on one of those addresses. This ...
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1answer
848 views

How to NAT behind public IP on pFsense before IPSEC to Cisco ASA?

I have two networks: Local 192.168.1.0/24 and Remote 10.8.8.8/24. On the local network I have installed pFsense as gateway. On the remote network there is a Cisco ASA that I don't have control over. ...
5
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2answers
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How to persist iptables configuration on Amazon EC2 VPC NAT Ami? [duplicate]

I have a small script like this to configure the iptables: #!/bin/bash PRE_STR="iptables -t nat -A PREROUTING -p tcp -j DNAT" FOR_STR="iptables -A FORWARD -p tcp -j ACCEPT" ...
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2answers
74 views

NAT UDP port switching? [closed]

I've read about the Quake 3 networking code that they had to deal with a situation where some older NATs would randomly switch client ports. How common is this issue these days? Is it worth handling ...
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2answers
667 views

IPTables: NAT multiple IPs to one public IP

I'm looking for a way how to nat 2 or more inner IPs (in my case xen doms) to one outer IP. I tried to use iptables -t nat -A PREROUTING -d 123.123.123.123 -j DNAT --to 1.2.3.4 --to 1.2.3.7 ...
5
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1answer
130 views

Route traffic directly between nodes in a cluster

I apologize if this is a really dumb question. Objective Ensure that traffic that is meant to go between nodes in a cluster does not (inefficiently) go outside the cluster and then come back in, but ...
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1answer
135 views

Using Linux just for doing QOS on an existing network

I have a proprietary web filtering device which also functions as a NAT router. It's one interface has a public IP and another interface has a private IP. All local clients connect to the interface ...
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1answer
523 views

1:1 NAT and ARP issue iptables

Gateway machine with 2 NIC one connecting public network and one for private network. Gateway: eth0 4.x.x.3 Eth1:10.10.11.3 There are 5 Machines with this as gateway all with ip 10.10.11.5---9 ...
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1answer
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Single Public IP for Multiple VPN Users?

I'd like to ask if I'm looking in the right direction. We have: 1 x VPN server (Windows SBS 2003) 5 x VPN users (One Public IP) Currently, from our remote office, only one user at a time is able ...
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3answers
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Forward traffic to local LAN IP while keeping the originator IP

I am trying to forward traffic from one server to another, while keeping the origin requestor IP. Therefor I cannot use SNAT or MASQUERADE. SERVER A: Public IP: 111.111.111.111 Private IP: 10.0.0.1 ...
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0answers
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Martian Source & Servers losing network

First off, I am pretty new at diagnosing network issues through linux. I have an intermittent problem with our LAN servers. They seem to lose all connection to the network and if I disable the adapter ...
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1answer
125 views

NAT one network to another using iptables

Trying to NAT ips in different network using iptables. KVM host with ip 10.10.11.36 on bridge br0. Two vms are running with ip 192.168.11.60 and 192.168.11.57 sharing bridge br0. Want to NAT all ...
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1answer
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VPN into private network? [closed]

I am trying to access a network in our office to allow access to a local server, this server is able to send out but is unable to be reached outside of the office network. Would it be possible to ...