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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Cisco IP Redirection (static NAT?) for non existant IP Range

We are moving office and our managed service provider has let us down badly. We have a Cisco 4500 stack with 5 VLANS configured of interest. These are: interface Vlan200 description FLOOR0 Gateway ...
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pfSense not forwarding back packets

I have a pfSense box setup where my WAN interface (em0) is set up in my local network (192.168.1.100) and my LAN interface (em1) is a private network of its own (10.0.0.1). The end goal is to have the ...
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454 views

pfSense Cluster not working with Manual NAT

I have two pfSense clusters, one is 2.1.4 and one is 2.1.3. The directions suggest that Manual Outbound NAT is required, but the 2.1.3 cluster is working just fine using Automatic NAT, servers and ...
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1answer
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Site to site VPN between Cisco VPN Router and Sonicwall NAT issues

I'm trying to establish a site-to-site VPN connection from office to datacenter. Cisco RV042G and SonicWall NSA2400 In the office; we have the subnet 10.0.0.0/24 defined and hosts from 10.0.0.150 to ...
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2answers
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Inbound SIP calls through Cisco 881 NAT hang up after a few seconds

I've recently moved to a Cisco 881 router for my WAN link. I was previously using a Cisco Linksys WAG320N as my modem/router/WiFi AP/NAT firewall. The WAG320N is now running in bridged mode, so it's ...
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How to set up IP forwarding on Nexenta (Solaris)?

I am trying to set up IP forwarding on my Nexenta box: root@hdd:~# uname -a SunOS hdd 5.11 NexentaOS_134f i86pc i386 i86pc Solaris The box has 2 network interfaces: root@hdd:~# ifconfig -a lo0: ...
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2answers
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Asterisk SIP/2.0 401 Unauthorized

I'm running into a funny little issue with Asterisk 10.3, but it seems to be applicable to 10.4 as well. The server running Asterisk was relocated from a VPS to dedicated hardware, and now only 1 of ...
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1answer
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Configure server to route all traffic through OpenVPN

I have an openvpn setup that is working great. There are some 50 clients connected and everything is handy dandy. I need one of these clients to route all traffic trough the vpn. I setup a ccd for ...
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2answers
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Initial Cisco ASA 5510 Config

I'm trying to set up a new ASA 5510. I have a pretty simple set up with one /24 on the inside NATed to a DHCP address on the outside. Everything on the inside works and I can ping the outside ...
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2answers
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Setting up a SIP NAT proxy

We currently run a VoIP server using an upstream providers SIP proxy for our clients who are behind NAT. We now have the problem that we re ending the relationship with the upstream provider, and will ...
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Setup 1:1 NAT using pfSense

pfSense box: Public IPs 208.43.30.118-.117 Private IP : 192.168.1.1 I need to provide 1:1 NAT mapping to a VM in the private network 192.168.1.5 I am unable to get 1:1 NAT working though it ...
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After upgrading BIND: Why is refusing requests? The server is on a NAT'd network

I already have a similar configuration working on another host with BIND 8.4.7 I'm migrating to a new name server so I decided to upgrade BIND to 9.7.3 The configuration is similar to this one, but ...
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2answers
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Can explicitly ftps via Filezilla but not from code

This was originally posted to StackOverflow, but because the code works and this is most likely a network/firewall issue, I figured I'd ask it here. As the title states, I can connect to another ...
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1answer
174 views

Finding a private (NAT) host's IP using historic destination data

The issue: An unknown private (NAT) client is infected with malware and it's trying to access a Bot server at random times/dates. How we know about this: We receive bot traffic notices/alerts from ...
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2answers
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IPSec Tunnel to Amazon EC2 - Netkey, NAT, and routing issue

I'm working on getting an IPSec VPN working between Amazon EC2 and my on-premise. The goal is to be able to safely administer stuff, up/download data, etc. over that tunnel. I have gotten the tunnel ...
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3answers
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Manual NAT on Checkpoint (Redirect all http requests to a local web server)

We have a proxy server in our internal network and I want to redirect all internet http requests to a web server in local network. It'll be like a Network Billboard that says "No direct connection is ...
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2answers
2k views

VirtualBox - Static Guest, accessible from host

I'm using VirtualBox trying to set up Windows as my dev environment, but an Ubuntu VM as my "virtual server". So, Windows 7 is my host OS on my laptop. My guest OS is Ubuntu, which will run my LAMP ...
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VPN between static IP address and dynamic and under NAT IP address [closed]

I have to connect two network like that: RemoteLan<-->Router3G/Firewall<-->INTERNET<-->Firewall<-->LocalLan So, I need to reach a device inside the RemoteLan from LocalLan. ...
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1answer
263 views

Logging NAT mappings on a Mikrotik router

I am looking for suggestions on how to configure a Mikrotik router to log NAT session setup and ideally teardown. However, setup only is sufficient for my immediate needs. I found a method to log ...
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0answers
730 views

ASA 5505: How do I access the DMZ web server from the inside using the public IP?

We are using a 5505 ASA Sec+ (8.2). There are three interfaces: inside (172.17.0.0/24), dmz (172.16.0.0/24) and outside (1.2.3.4 for the example). There are static NAT rules set up translating 1.2.3....
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Reaching out DHCP relayed hosts

I have one primary server (DHCP) and one secondary (DHCP-RELAY). Majority of hosts are served from primary (wirelessly), however there are a few (wired ones) which get their IPs from secondary. ...
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548 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
356 views

NAT box load-balancing with iptables and 4 DHCP uplinks

I am trying to configure a router which provides Internet to a couple hundred users. This router has 4 basic cable uplinks at its disposition, which all use DHCP and have a capacity of around 10/1 ...
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563 views

Oracle Solaris 11, ipnat - rdr not working with remote destinations

I'm trying to reverse proxy traffic coming in on port 8100 at one machine to another. The receiving host is an oracle exclusive zone as is the destination machine. On the incoming zone I have ...
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2answers
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sonicwall vpn and NAT

I have a site-to-site VPN set up with a vendor. Let's say the tunnel endpoints are 192.1.1.101 on my side and 192.1.2.0/24 on the vendor's side (which get's NATted to their LAN of 10.x.x.x). This is ...
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5answers
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Open ports broken from internal network [duplicate]

Quick summary: Forwarded port works from the outside world, but from the internal network using the external IP the connection is refused. This is a simplified situation to make the explanation ...
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1answer
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What is strict, moderate and open NAT?

NAT options on domestic routers often come configured as strict. What does this mean? What do moderate or open do? Port-forwarding/DMZ access works properly on strict so why bother with the other two? ...
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4answers
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Is there still any legitimate reason (in 2011) to use proxy servers instead of NAT for sharing an internet connection?

Proxies were around before NAT, and so early on in the internet, they were popular ways to get an entire network online with only a single public IP. NAT initially required complex software and/or ...
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4answers
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How to properly nest a wireless router behind a wired router? [closed]

I wish to repurpose a wireless router to serve as a wireless access point behind a wired router (serving as gateway to WAN) so that I don't have to buy more hardware and recapture value on prior ...
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3answers
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Iptables massive 1:1 NAT

I have to connect two LANs: LAN1: 10.10.0.0/16 and LAN2: 192.168.0.0/16. I can't do simple routing, because 192.168.0.0/16 net is prohibited in LAN1, so I am thinking of using Full cone nat (1:1) to ...
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Windows Computers Joined to a Domain Behind NAT

If I have some Windows XP machines that are behind NAT, will all services still work as normal such as file sharing, printing, etc. The setup would be something like 192.168.20.0/24 NAT`ed to 192.168....
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2answers
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Server becomes unreachable and comes back up on its own (most likely a network issue)

I'm having a strange problem with a server I have sitting at my workplace (it's behind a NAT, if that's important). The issue is that at some times, it becomes unreachable and then comes back up again,...
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2answers
409 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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2answers
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Iptables string

I have an iptables rule like this: iptables -t nat -I PREROUTING -p tcp --dport 80 -s 192.168.1.2 -j DNAT --to-destination 192.168.1.1:80 it works perfectly.. but I want to redirect only for one ...
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1answer
107 views

How can I Nat certain boxes in my datacenter so that they are coming from a single IP

I want to NAT a certain group of servers in my datacenter so that they all access clients from a single IP. This will make it much easier for documentation that we provide clients. However there ...
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3answers
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Reloading NAT configuration on a running VMWare Server 2.0.2

I have a server running VMWare Server 2.0.2. The host is Debian Lenny. I have 15-20 virtual machines running, all attached to a single NAT network (named vmnet8). I have configured VMWare's NAT (the ...
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3answers
855 views

Can I have web server on a home network with 1 public IP address? [closed]

I've got a fairly standard home network with a modem from my ISP, which is connected to a router which then provides NAT to about 3 PCs and laptops. There's a possibility to obtain one public IP from ...
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4answers
801 views

Is NAT completely transparent to a host?

Can we find a sequence of packets that a host can transmit to determine whether it is located behind a NAT box? I mean, without any special server support like STUN.
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4answers
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Trying to setup NAT from 2 outside IPs to the same private IP

Cisco ASA 5510 I currently have a NAT for SMTP on one outside IP to an internal IP. I need to setup 2 external IPs to NAT to the same IP internally. How can I do that? ex: 10.10.10.1 25 --> 192.168....
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3answers
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How to implement Nat loopback/reflection?

I'm trying to access a server on my LAN via its public IP address. External clients can connect just fine, but I'm unable to do so from within the LAN. There is a separate rule in the NAT settings of ...
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1answer
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Cisco ASA 8.4 port forwarding

I am having trouble port-forwarding on an Cisco ASA from a host on the internet to a host on the internal network. The outside interface of the ASA is assigned via DHCP. Is there something else that ...
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2answers
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UDP and NATs - is the timeout bidirectional?

Is the timeout for an UDP connection through a NAT reset every time a packet is sent OR received by the client, or are there any (common) implementations that require the client to actively send ...
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3answers
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VPN software similar to Hamachi, Remobo or GBridge?

I am looking for a VPN software that will run on Windows (Mac/Linux would be a bonus), that are similar to other packages such as Hamachi that will automatically work behind a NAT or Firewall. Also,...
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Networks, subnets, routing and NAT

What I'm going to ask may be trivial but I really need to understand cause my teacher is confusing me! That's the problem. I got 2 private networks The first is a class C network and the address is ...
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336 views

Does the ELB also route outbound reply traffic in AWS

I have been trying to understand how routing works in an AWS VPC with public/private subnets. I have a setup as recommended by amazon with an ELB and NAT in the public subnet and the webserver in the ...
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2answers
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Make CentOS 7.x a port forwarding NAT device

I would like to make CentOS a port forwarding NAT machine using iptables. This is the first time I've tried this and I think i might need a little help. This is the configuration i'm trying to ...
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2answers
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IPtables NAT puzzler: Why is traffic from the firewall host being NATed even though it's not coming from one of the prescribed source addresses?

I run a small network where a linux web/mail server also provides NAT for a collection of windows boxes. One of these windows machines is apparently misbehaving (ZeroAccess botnet even though I can't ...
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2answers
300 views

Networking several devices with the same IP

I have a bunch of embedded devices that I need to flash with a custom OS. On each device, the boot-loader (U-Boot) has a fixed IP of 192.168.100.2 and on boot it looks for a TFTP server at 192.168....
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2answers
4k views

How can I setup a Firewall without NAT?

We have 16 IP addresses from our ISP, and are setting up a SonicWall Firewall. I'd like to have the SonicWall do NAT for the LAN, but act as a firewall only (no NAT) for the servers which are using ...
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Port Forwarding

Assuming port forwarding is done on router, can the router forward if the data is coming from local machine, rather than remote. For example: Sender targets ip like:88.251.xxx.xxx, port 8999. ...