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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Reverse proxy server that accepts connections from HTTP server - does it exist?

I'm the developer of an embedded hardware device which contains a lightweight HTTPS server. The problem is that I wish for the embedded device's web server to be accessed from outside when placed ...
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1answer
20 views

NAT to two different servers on the same port via hostname with Mikrotik RB2011

I have a Mikrotik RB2011 router, running RouterOS which connects to the internet via a static IP. In my lan I have two different servers, one that is on IP 192.168.89.11 and another on 192.168.89.12 ...
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28 views

dns config for nat with BIND [on hold]

Over the past days, i installed CentOS on a computer that I'm using to mess around with system admin related tasks. What im doing is, I'm basically making this computer into a "super router" as i like ...
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0answers
7 views

Microtik router intervlan routing with NAT

I have setup as below: MTik Router RB450G(ether1) --> (fa0/1) Cisco Switch (fa0/2) --> Maipu Router, Internet Router MTik Router(ether2) --> My PC In fa0/1 , there are two VLANS trunked: VLAN 10, ...
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0answers
11 views

Inbound redirects using ProxMox to NAT VM not working

I have configured ProxMox on a Hetzner Root Server. Its configured using their image under "Virtualisation". Once it was installed I could create a VM and its configured using NAT. This server gets an ...
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0answers
40 views

Amazon VPC NAT performance problems

I have a set of servers inside an Amazon VPC, whose job is to get image files from S3 and process them. The S3 downloads would frequently stall, sometimes for over 2 minutes, but all would eventually ...
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0answers
28 views

OpenVPN server cannot ping client (routing/iptables issue?)

I am not sure exactly where the issue is here. I'm fairly sure that this is some NAT or iptables issue on the OpenVPN server but am lacking the networking know-how to fix the issue. The crux of the ...
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20 views

Can NAT be used for a br-ex OpenVSwitch interface (VirtualBox)?

Can "NAT" be used for an interface (eth1) which has a br-ex attached to it using OpenVSwitch or does it have to be "Bridged Adapter"? (VirtualBox) /etc/network/interfaces on Ubuntu 14.04 auto eth1 ...
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1answer
29 views

Expose a machine on the far side of a VPN

We're using a VPN to connect a remote office to our main office, and a machine in the remote office needs to expose port 22 to the outside internet. Complications: The main office has a fixed IP ...
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13 views

Blindly bridging wireless client with MAC NAT

This is the usual "I want to bridge wifi with ethernet" question, but I need something specific here. My Linux box has a wlan0 interface which is in station mode, with MAC aa:aa:aa:aa:aa:aa, and a ...
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1answer
17 views

getting to server on internal network with the external address

I have a network behind a nat with exchange server. Mobile device are configured to access exchange using its real address (the single ip that the entire office hides behind) When the mobile device ...
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22 views

Slackware internet gateway with iptables / poor browsing performance [migrated]

I am running a dual core headless computer as internet gateway via pppoe with two NICs. eth1 (internet interface) no ip, no dhcp eth0 (LAN interface) - 192.168.0.100 static ppp0 - dynamic ip ...
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25 views

ASA 5515-X: Policy based NAT for dedicated uplink

We have bought a Cisco ASA 5515-X and we have the following scenario. Current situation: GigabitInterface 0/0, IP via DHCP, ISP1, Coax, 100M up / 12M down, medium latency GigabitInterface 0/1, ...
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1answer
25 views

Why Use a NAT Instance? [closed]

Consider the following VPC: Public subnet with app servers and a separate NAT instance. Private subnet with database server. What benefits do we gain by using a stand alone NAT? EDIT: Why use ...
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17 views

Routing and RAS with multiplice public IP-Adresses

I have two public ips, e.g. (1) = 111.111.111.1111 and (2) = 222.222.222.222 on one NIC of a Windows Server 2012 R2 Server. I'm using "Routing and RAS" to forward some ports by NAT rules to Hyper-V ...
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1answer
23 views

Apache presents wrong certificate when accessed via load balancer [duplicate]

I've got a server that has two SSL certificates set up, one for internal access where it is accessed along the lines of host.my-local.net and other for external access where it is accessed similar to ...
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2answers
23 views

Could I have 2 nat on vpc [closed]

There is a vpc on amazon that has two subnets. The outer one has internet access and the inner one using NAT server to connect to internet. Inner subnet have plenty of servers for development and ...
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1answer
76 views

Internet access from private VPC subnet?

My brain is a little bit fried trying to figure this out but I can't seem to get private subnets to connect to the internet to grab updates for example. Basically all I want is web access for these ...
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3answers
87 views

Forward Traffic in & out, NAT iptables

I have a box setup as DHCP Server with NAT ipv4 forwarding enabled. Currently the box uses eth0 to connect to a local network and has access to the internet, it has another 3 interfaces, eth1, eth2 ...
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1answer
42 views

Cisco static NAT not working on LAN side

I have a web server in my private network that has the ip address 192.168.1.134. I need to allow users to access this web server from both the internet and the private network. The public ip address ...
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2answers
172 views

OpenWRT Barrier Breaker - Router does not route

I've upgraded my TP-Link 1043 router to OpenWrt 14.07. Everything is perfect, Wifi and LAN are bridged, LAN machines can access each other by name, I can SSH into the router, and the router can access ...
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1answer
38 views

Force Cisco ASA to change source port NAT

I have a 2 devices, a Cisco ASA and sitting behind it another device. Both the Cisco and the other device have IPsec tunnels but to different locations. I need to ensure that the source port of the ...
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2answers
226 views

Amazon EC2 VPC: NAT instance download speed performance drop

I have a set of servers inside Amazon EC2 in VPC. Inside this VPC I have a private subnet and a public subnet. In the public subnet I have set up a NAT machine on a t2.micro instance that basically ...
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2answers
47 views

How to redirect a packet with iptables that match a certain pattern? (eg a QUERY command with UDP)

I have a certain packet that I want at all times to be redirected to a specific ip on my virtual network interface. As for now my iptables is setup like this: (the commands, I use \ as for now to ...
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1answer
25 views

How to route an IP Whitelist to one VM and all other to a second VM on proxmox?

Is it possible on linux to have a whitelist of IP's that are allowed to reach a specific VM on the internal NAT? eg (public ip (proxmox) --> My VM for whitelisted IP's (192.168.0.1)), and if the ...
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2answers
144 views

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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1answer
36 views

Are iptables prerouting (DNAT) packet changes visible to subsequent chains?

I was reading Rusty Russell's NAT Howto when I came across this section: 6.2. Destination NAT This is done in the PREROUTING chain, just as the packet comes in; this means that anything else on ...
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1answer
116 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
145 views

AWS EC2 Ubuntu 14.04 Instance smtp port forwarding from 25 to 2025

I am trying to step up port forwarding from port 25 to port 2025 on the same AWS EC2 Ubuntu 14.04 instance using iptables. I am using port 2025 to receive income emails using Alfresco. The first step ...
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2answers
98 views

Static public IP issue on Cisco ASA 5512x

This is our scenario: We have an Cisco ASA 5512x and we have 2 different Internet connections from different ISPs connected with it. ISP A is being used for the users browsing traffic(normal ...
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0answers
9 views

iptables NAT can't initialise on Debian openvz [duplicate]

So i want to create a nat rule for an openVPN server. After getting trouble with the TAP/TUN Devices, it's finally working i think It's working greate but not routed so useless. Now i have to make a ...
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1answer
51 views

Forward incoming packets from port 25565 to natted internal client? IPTables [closed]

I have been learning to use iptables recently and i made a small nat network in virtualbox. I have a Debian server Natting for the internal clients. One of the internal clients is hosting a minecraft ...
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0answers
61 views

Ubuntu as IPSec L2TP client with NAT traversal

Goog afternoon, I have a corporate local network located behind NAT. There is another NAT in this local network for the corprorate server on Ubunit 12.04. So if clients connect to that server ...
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0answers
55 views

SFTP Reverse-Proxy using iptables on custom port

I want to give SFTP access to anyone into to my Server (IP: ss.ss.ss.ss) passing through Proxy (reverse-Proxy? IP: pp.pp.pp.pp), so that IP ss.ss.ss.ss is never seen by whoever is connecting to the ...
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1answer
43 views

Can I use an external IP to make 2 internal IP's establish a TCP/UDP connection? [closed]

As I understood, in order to make a connection to an internal IP (behind NAT), the computer behind the internal IP have to send the request first before the other side will be able to answer it, So if ...
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0answers
82 views

iptables - dropping specific established connections after X hours

Is there a way with iptables to drop specific established connections after X hours? We have an application with limited connection support, and occasionally we see some tcp sessions that shouldn't ...
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2answers
62 views

Is it a security improvement to use NATed network?

There is a website that blocked an ISP's subnet (because attacks came from that network). The ISP gives it's users only NAT'ed IP addresses, so the clients are geting 10.x.x.x IP addresses on their ...
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1answer
59 views

How to start with IPv6 subnetting on linux gateway

We are currently having perfectly working IPv4 network with a typical layout - internal network with all servers splitted to VLANs in 10.0.0.0/8 (each vlan is /24) and external network with public ip ...
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1answer
120 views

How to trace dropped TCP connections?

Trying to help someone with a situation where TCP connections get mysteriously dropped after a few minutes for no apparent reason (this happens even with non idle connections). Both client and server ...
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1answer
121 views

Proxmox VE: Multiple shared public IPs with NAT configuration

I have a Proxmox VE (v3.3 @ Debian 7 Wheezy) and got 3 public IPs routed to that server. It is my aim to have multiple VMs sharing those IPs using a NAT configuration so that I can forward single ...
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2answers
98 views

Forwarding HTTPs requests to another webserver

I have an Ubuntu 12.04 Server connected to two subnets. Eth0 is 20.20.20.1, it hosts an Apache Web Server on port 80. Eth1 is dynamic IP address in 10.10.10.0 subnet. This server is not a gateway ...
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1answer
72 views

Can't set up the default route from a sublan to the WAN [closed]

I am trying to connect one of my PCs to the Internet via a WiFi network using a notebook. Here is my network : (Wifi) <=============> (Notebook) <===============> (Desktop) ...
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1answer
47 views

iptables with sticky forwarding/routing

My iptables is sticking. I have a DNS server behind IPTables and down a NAT'ed OpenVPN pipe. Using tcpdump I see DNS packets hit the outside router but it takes 4 or 5 DNS query attempts before the ...
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1answer
41 views

Keep source port for outgoing packets

I have 2 interfaces eth0(192.168.0.1) and eth1(10.1.1.15). And I do nat for all packets in this way. iptables -t nat -A POSTROUTING -s 192.168.0.0/24 -j MASQUERADE Now I want to keep source port ...
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1answer
39 views

Proxmox with iptables nat is not available

I got an issue with iptables on my virtual machines. I installed proxmox 3.1-21 on my rootserver. I have around 6 IPs linked to my rootserver so i created new 'CT's. The problem is i need to ...
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0answers
58 views

Debian forward through NAT EOIP GRE

eth0 = WAN eth1 = LAN to forward any port through nat I use e.g: iptables -t nat -A PREROUTING -p tcp -d 79.188.31.34 --dport 8291 -j DNAT --to-destination 192.168.0.36:8291 and it works, but ...
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0answers
125 views

Linux router with multiple gateways and port forwarding

I want to use a Linux VM to act as several routers at once. I have multiple servers hosting different services and dedicated public IP for each of them. Super simplified setup example: Ubuntu ...
2
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0answers
111 views

Apache Instance in Private Subnet not returning packets

How can we get the Apache instance in a private subnet to work? Configuration Public subnet with 1 NAT instance Private subnet with 1 App instance Details 1. Masquerading is turned on NAT on via ...
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0answers
36 views

Should a NAT host be separate from a Bastion host

Have a private network with servers that required SSH access. Since the instances are in a private subnet, they cannot be accessed directly via SSH and require a public Bastion host to access. ...
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2answers
212 views

Using Router with DHCP and NAT and Windows Server 2012 as DNS

I have a network currently set up as per the image below. We use Regus's shared Internet and I've create a sub network for our office by using DHCP and NAT on the airport extreme router. Now the ...