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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Windows Server 2003 IPSec Tunnel Connected, But Not Working (Possibly NAT/RRAS Related)

Configuration I have setup a "raw" IPSec tunnel between a Windows Server 2003 (SBS) machine and a Netgear FVG318 according to the instructions in Microsoft KB816514. The configuration is as follows ...
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236 views

Multi homed firewall with ipnat

i am trying (without success) to configure a ipnat/ipf box under FreeBSD 8.2, here is the scenario: outside inside +----+ ADSL ...
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1answer
119 views

Stateless NAT with CentOS 6

I'm looking to set up the following: ---[IVR 1] | (internet)----[CentOS box]---+---[IVR 2] | ...
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1answer
159 views

website not accessible with IIS6 while NAT is configured in Windows 2003

I have Windows2003 server configured with IIS 6. Until now it was working fine, but since I enabled NAT for my users to access the internet via this server, the website becomes unavailable. Note that ...
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1answer
121 views

OpenVPN tunnel, iptables don't support NAT

I wanted to route my private PCs traffic through my VPS and set up my OpenVPN as fas as necessary but now I have the problem that I can't set iptables, since NAT support is disabled for my server's ...
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24 views

Route new outbound traffic

I am looking for some iptables rules which can help me to route some traffic from a server : Client 1 ----| Client 2 ----| |----------| Client N ----| ssh, ...
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1answer
37 views

Apache can't access from wan on archlinux

Information: Archlinux via vmware Have ports 8080, 443 and 80 forwarded to the local ip from router running pfsense I can access the webpage from lan via local ip. My httpd.conf: Listen 80 ...
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1answer
35 views

IP forwading amazon ec2 another server IP

I use this command in windows azure (NAT), to redirect all requests to another server with other IP iptables -t nat -A PREROUTING -i eth0 -d 10.240.154.15 -j DNAT --to-destination 192.188.47.63 ¿ ...
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178 views

How to forward ports to DMZ using iptables and separate modem

I have a network that looks like this: ADSL VLAN 2 VLAN 3 ------[Modem]----------[firewall]----------[intranet PC] | | ...
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326 views

My iptable rules do not allow VPN connections

I have installed OpenVPN on my Archlinux server and modified my iptable rules to allow incoming traffic on port 1194 and forward it to the tun0 interface. When I disable/stop the iptables, the OpenVPN ...
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1answer
87 views

Websever behind Sonicwall, Gateway Timeout

I am stuck here, I have a Cradlepoint CBA750B in IP-passthrough mode connected to x1 on my Sonicwall NSA220. Behind the Sonicwall I have a webserver on the LAN. I have X1 set to use DHCP to get the ...
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1answer
207 views

Access Apache VirtualHost from localhost

I have a DirectAdmin setup with Apache on a server which is behind NAT. Everything is working correctly when accessing a VirtualHost from outside the machine (either through the Internet and the ...
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1answer
355 views

Redirect traffic on port 80 into apache for unknown macs, and into squid for some macs

I have a linux box behaving like a router that handles two network interfaces: eth0 for internet and eth1 for LAN. I set up iptables in order to redirect all the web traffic coming by the LAN into a ...
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1answer
405 views

iptables can drop traffic but cannot redirect

Suppose that TCP packets are sent to destination ip (dest_ip) and can be dropped by the following command: iptables -A INPUT -d dest_ip -p tcp -j DROP But when I try to redirect the packet using ...
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1answer
264 views

Passive FTP that would work inside and outside of NAT

I'm using vsftpd 2.2.2 behind the NAT. To make it work, I set pasv_address to my external (internet) IP. Now the problem is with clients that connect it through the LAN - they try to connect to the ...
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295 views

Setting up IP masquerading by passing packets through external nodes

I'm trying to find a solution to prevent remote machines determining the source IP of my webserver. This is to hide the webserver's actual IP, helping avoid DDoS attacks. Incoming requests are ...
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1answer
369 views

Connect KVM virtual network to internet

I have a CentOS server running KVM and need to connect a virtual network to the internet. The network must be routed or NATted, it must not be bridged (port security). If possible, I would like to ...
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1answer
115 views

Open VPN redirect all trafic from TAP/tun interface to netowrk interface

I want all my traffic redirected to the OpenVPN tunnel. I used the directive push "redirect-gateway def1" but the Tap interface on the server is not routed to the internet. How can I do it on ...
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475 views

Virtual box linux routing

Sorry for the basic question but I cant figure this one out. I want to set up a small network of linux servers for testing purposes. So I have a host server running virtual box with the following ...
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71 views

Simple MASQUERADE NAT between 2 VM

I'm on a cloud service and I'm trying to set up NAT between two VM. I've never experienced issues in this simple step, but this time is different and I'm near to give up. The first VM had two ...
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131 views

Cisco ASA Access anyconnect from inside IPsec tunnel

I have a Cisco ASA on a dynamic WAN IP with a IPsec site-to-site tunnel to a remote linux host in a datacenter with a static WAN IP. All non local traffic is tunneled and the datacenter end is the ...
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267 views

Cisco ASA 5505: PAT / NAT between 2 IPSec Tunnels

I've the following Setup: Customer <-> HQ <-> Branchoffice The Customer has a 192.168.1.0/24 subnet. On the HQ only the VPN Gateway is in my context, 172.20.10.1 . And on the Branchoffice ...
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134 views

Linux routing: How to allow a device inside private network to connect a public IP over an unknown network?

Consider following network topology: ---------- ---- (my network) ---- | Device 1 | (.101) | 192.168.191.0/24 | ---------- | | ...
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147 views

KVM : domain names are resolved, but cannot ping

I've found that in KVM, my networking is acting funny. Oddly (1) I can resolve external internet locations using nslookup or ping , but I cannot actually receive a ping back. (2) I cannot ping ...
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426 views

UDP packets are not reaching iptables NAT table

I'm trying to redirect UDP incoming packets to port 4000 to another IP with iptables: iptables -t nat -A PREROUTING -p udp --dport 4000 -j DNAT --to-destination 192.168.100.20 Unfortunately they ...
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39 views

Using NAT with iptables between corporate network and firewall'd corporate network

At work we have a firewall between two networks. I was told they opened up the two ports for me but I needed to modify the IPtables to allow packets to go through. I'm not familiar with the correct ...
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90 views

Listening “through” GRE Tunnel

Currently I'm looking to learn about using GRE Tunnels and I have the following scheme: Server1 (200.1.2.3) ----> Server2 (190.1.2.3) Both servers have public IPs Then I've setup a GRE Tunnel with ...
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348 views

Cisco router: expired translations not timing out

Why would a Cisco router stop removing expired translations from the NAT table? For example: #show ip nat translations tcp verbose tcp <loopback>:60576 <inside>:60576 ...
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501 views

Port Forwarding to a VPN Client

I'm looking for some help getting a port forward setup to a VM running Ubuntu 12.04 on my LAN. I can forward the port to the VM successfully and connect to the service over the Internet. But when I ...
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72 views

NAT answers instead of remote host

Currently I have VPN client access set up on OpenSuSE 13.1 server to third-party remote Cisco VPN IPSec server. VPN Server is set up to provide access for a host only and to provide access for a local ...
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574 views

pfSense NAT routing using VLANs

We already have pfSense installed and it is working for our single IP address on 1.1.1.1. We also have a further 3 ip addresses (1.1.1.2, 1.1.1.3, 1.1.1.4) which are set up as VLANs on the WAN ...
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73 views

With split routing configuration returning packets don't reach their sender

I am trying to configure a split routing setup, where all traffic goes out the default eth0 interface, while packets from a single client are routed via tun11 (OpenVPN interface). So far I've come up ...
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80 views

Is there an optimal NAT configuration in Cisco IOS for peer to peer applications?

The Cisco router in my organisation is set up to use Port Address Translation (PAT) for Internet connectivity. ie All outbound internet connections are from the ip address or the border Cisco ...
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41 views

Impact of iodined settings to server

I would like to install iodined, the IP tunnel via DNS, on a working web server. However, the configuration requires to set IP forwarding add NAT masquerading rules to iptables (and open DNS port) ...
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40 views

Is it possible to hairpin on Cisco 851W IOS 12.4(15)T9 and how?

I need machines on the LAN to be able to access by the external address or hostname. If it can't be done, then just by hostname is OK as well, so I thought of just doing it through DNS on our internal ...
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174 views

FreeBSD ipnat(8) rdr - not redirecting

I'm using FreeBSD-10.0-RELEASE: root@fx:~ # uname -a FreeBSD fx.alexus.org 10.0-RELEASE FreeBSD 10.0-RELEASE #0 r260789: Thu Jan 16 22:34:59 UTC 2014 ...
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196 views

Load-balancing PPTP connections

I'm trying to load balance two PPTP connections, connected to the same server. I use the following script, but there is no send and receive via PPTP connections. What part am I doing wrong? Are there ...
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81 views

Multiple routes and gateways with NAT

My setup is a VM host with two network interfaces where I want to use one as private/internal and the other one as public (which will get a public address on the host), where all the NAT magic to the ...
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537 views

Windows Server 2012 R2, multiple Hyper-V Virtual Network Switches for multiple VMs

I want to configure something like this: I have one NIC, and have been given 3 IPs by datacenter, on my server which is running WS2012R2, with 10 VMs on hyper-v. Windows Server 2012 R2 (host) one ...
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174 views

Why is an ack response being sent to the wrong gateway?

I was trying to determine why a packet forwarded by iptables to my internal lan is returned on the wrong gateway. Having investigated this further, I determined that, at least in the case of one of ...
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59 views

Where can I find the range of IP addresses of my container OpenVZ

I'm looking for the "range of IP addresses of my container"... Where can I find those ? /etc/network/interfaces ? ifconfig ? I don't know and I can't find any answers... I need it for this tutorial ...
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180 views

Amazon EC2 Nat Instance - goes out but not back in

I've followed Amazon's steps and list what I've done. I've created 6 subnets (4 private SN1: 10.50.1.0/24, SN2: 10.50.2.0/24, SN3: 10.50.3.0/24, SN4: 10.50.4.0/24) and 2 public (SN5: 10.50.101.0/24 ...
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339 views

Socksify TCP connections reaching a gateway IP — preferably without iptables

I have Virtualbox installed on Debian with a few virtual machines. I can't install anything in the guests, and I use host only networking, vboxnet0. The host IP in the host network is 192.168.56.1, ...
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223 views

Cisco ASA, Windows Server 08, PPTP/GRE issues

I am at the end of my rope on this one. I am trying to simply forward pptp/gre through a Cisco ASA to my Windows server. Here is what I have done: Access Rules: OUTSIDE ...
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325 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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107 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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964 views

Cisco 1921 - Using NAT (NVI method) between VRF's slow performance

I'm setting up a Cisco 1921 with two VRF's: one to the internet and one to the LAN. The LAN is in private address space so source address translation needs to happen when the packets leave the ...
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117 views

Why NATted packets have different source ip addresses?

I've got ubuntu box with nat. Here is the problem: root@office.redhelper.ru:~# tcpdump -i tap0 host 194.190.8.141 -n tcpdump: verbose output suppressed, use -v or -vv for full protocol decode ...
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191 views

set DMZ server on modem that not support DMZ, using port forwarding

I have to see an application server from outside of my network, but the modem that I am using is a Zyxel P-660-HN-T1H that not supports DMZ server configuration.So, which port(s) I should forward to ...
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164 views

Multihoming, NAT and ICMP

My router is the default gateway of a LAN and is multihomed. ISP2 is used for HTTP, HTTPS and ISP1, the default gateway of the default routing table, for the rest of the traffic. Similar questions ...