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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iptables DNAT packets into an openswan IPSEC tunnel

I have the following network setup: +-----------------------------------+ | | +-------...
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1answer
90 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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2k views

can't connect aws VPC private instance to internet through NAT

trying to install a LAMP stack on an aws instance in a VPC private subnet using Scenario 2 described here: http://docs.aws.amazon.com/AmazonVPC/latest/UserGuide/VPC_Scenario2.html I've set everything ...
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203 views

CentOS 6.6 ignores iptables nat rules

I try to use iptables nat to forward incoming TCP traffic to another computer. I use following rules within nat table: -A PREROUTING -i eth3 -p tcp -m tcp --dport 8888 -j DNAT --to-destination 192....
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1answer
329 views

c7200 IOS 15.x-x NAT/PAT issue

My problem may be just finger trouble, but after fighting with this for a day on what should have taken 5mins, I am getting fustrated. I am not Cisco Certified at any level, just a fair amount of ...
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2answers
366 views

TCP traffic on port 1433 blocked by NAT rules

We have a SQL server that is hosted on AWS, the SQL server it not directly accessible on the internet, it relies on a NAT box to route traffic to it. We are trying to set up a Linked SQL server from ...
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0answers
95 views

iptables keeps using old nat rules

I use iptables snat on my gateway to change local source ip addresses to external. The trouble is that after I change the rules (or even if I flush iptables nat table) gateway keeps using the old rule ...
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2answers
371 views

PFSense IPSEC VPN VLAN

We are integrating with a third party and they require the use of a L2L IPSec VPN for communication. I have successfully configured the IPSEC vpn and the tunel is up but now I cannot seem to have ...
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2answers
826 views

SIP Trunk for VOIP behind a SonicWALL

I appreciate this question is quite "out-there" but - has anyone had any success with VOIP over SIP behind a SonicWALL. We are having an issue with one-way audio inbound. Essentially, the person ...
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1answer
658 views

Which SSL certificate would I need for external AND internal domain names?

This is a school-network. Official (outside reachable domain name) is bgschwechat.ac.at (www.bgschwechat..., mail.bgschwechat... and ftp.bgschwechat..) Internally the windows domain is named bgs.ac....
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2answers
260 views

NAT-ing with iptables rewrites source IP in logs

I have the following infrastructure in place: internet [outside 81.x.x.x] router [inside 192.168.1.1] | [network 192.168.1.0/24] ...
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2answers
599 views

router: ping fails at specific time for 40 seconds

my network looks like this: ISP cable --- ISP modem/router (2 in 1) \ \--- my router --- wifi connection --- computer 1 \----------- cable connection --...
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1answer
125 views

Windows Server as a PPTP Gateway

I have a Windows Server 2012 server at work, which is currently used as a domain controller, and an internet gateway. The current internet connection uses a USB dongle, which appears like a standard ...
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0answers
935 views

FortiGate 310B public ip pool into internal port

I have a FortiGate 310B with WAN port with /27 public IP pool from the ISP. The WAN port is configured with primary IP 1.1.1.1/27 I would like to provide servers within the Internal port a public IP. ...
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383 views

Cisco ASA firewall blocking requests to internally hosted DNS server

I have a DNS server behind a Cisco ASA firewall. The Cisco firewall is performing NAT. When inside the network, I can NSLOOKUP directly to the server. When the client is external, requests time out. ...
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2answers
458 views

Reaching Local Network which is under NAT with no public IP

I have a place called (lets say) REMOTE. REMOTE is connected to the Internet using 3G/4G Modem + Router. Unfortunately my mobile Internet provider does not give me public IP address. In REMOTE I have ...
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1answer
355 views

Cisco IOS - Problems with NAT and port forwarding

I have a problem forwarding ports. I have configured a NAT pool of 1 address (192.168.5.2) and assigned that address to the WAN interface. I assigned networks to the access-list, and bind the two ...
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1answer
533 views

Forwarding a port on the loopback interface to a remote IP/port

I have two Docker containers that I'm trying to network together in a specific way. Container A is running a Redis server on port 6379. Container B is running an interactive shell and needs to access ...
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1answer
1k views

AWS public subnet autoscaling group with outbound NAT

I have seen this question : Static IP address for outgoing traffic from AWS autoscaling group but it doesnt seem to fit exactly what im trying to do. Here's the scenario: I have a autoscaling ...
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2answers
756 views

iptables drops packets after POSTROUTING

I have a malware analysis environment that will intercept traffic to arbitrary domains and Internet services using InetSim. I have a sandbox that has its DNS server set to the InetSim instance, and ...
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2answers
48 views

Trying to use source routing on two different interfaces

I have defined the following rules: -A POSTROUTING -j SNAT --to-source [publicip] -A POSTROUTING -j SNAT -d 192.168.0.0/24 --to-source 192.168.0.6 Basically, I want only the private network to go ...
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5answers
639 views

Router limits network performance but its CPU load isn't 100%

I'm using a PC Engines APU device running FreeBSD as a NAT router. The setup is very usual: one WAN connection and one LAN connection. Theoretically, WAN connection is 800/40 Mbit/s and the LAN one ...
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3answers
249 views

Cisco ASA NAT - internal host see its public ip

I have a server hosted by a provider which uses Cisco ASA to do nat. The problem I have is that the internal server that is nat-ed with a public ip will see its public ip as source ip. This basically ...
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214 views

Chaining two containers with docker

I have two containers that I have chained them together, so traffic that comes to container 2, first passes by container 1. I set container 2 --net=none. Host --- Container 1 --- Container 2 this is ...
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2answers
1k views

NAT a single IP using 2nd WAN Internet

I have a mikrotik RB750 (6.22) acting as a gateway for my LAN. Here is the basic configuration: Ether1-WAN1 (1.1.1.10/24) IPs are hidden for privacy Ether2-WAN2 (2.2.2.20/24) Ether5-LAN (192.168.1.1/...
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745 views

Why can't I SSH to this AWS NAT instance in a public subnet?

For experimentation purposes, I’m trying to setup an AWS EC2 inside a VPC that has both public and private subnets as described in this tutorial. However, when I try to SSH in step #2, it fails (...
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1answer
36 views

How to find how a port has been forwarded from main server to hypver v vm

I must appologise for being a novice in server administration but I have somehow been given the responsibility and I have spent a long time reading up on this. The issue I have is that the previous ...
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1answer
599 views

Use Openswan / IPSec on Ubuntu server to connect to existing Openswan VPN - NAT broken

I have an existing Openswan VPN, all working fairly well with Windows, Mac and Phones. [Office 192.168.0.0/24]---[VPN A.B.C.D]----[Internet]---[Home Routers (NAT), Dynamic IPs]----[Workstations] Now ...
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1answer
80 views

iptables port forwarding from public ip but not from 127.0.0.1

i have an issue with my network setting and i need a port forwarding a bit advanced. I need : - All packets that arrive on my public_ip on port 54321 to be forward on port 12345 but i don't want any ...
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1answer
1k views

Asterisk behind NAT sets wrong Contact Header

I'm using SIP with asterisk 13.1.0 behind a statically configured NAT. The servers private_ip differs from the public_ip, where I can reach it. I've already set these options in the sip.conf file. ...
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2answers
86 views

Port forward for SSH works to one system but not another

I have two systems sitting on a NATed network. When I forward port 22 to system A, I am able to connect directly. When I forward port 22 to system B, I am not able to connect. I am, however, able to ...
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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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1answer
860 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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1answer
262 views

Linux firewall, ADSL bonding, two default routes

I am trying to set up a Linux firewall (ubuntu 14.04) to use two bonded ADSL lines for load balancing purposes. I found by searching the forum link to this: http://lartc.org/howto/lartc.rpdb.multiple-...
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1answer
63 views

Is there any solution to change the source IP from outgoing WAN A to receiving WAN B?

I am configuring a office router for crossing the GFW in China. I want to use WAN A(actually a low bandwidth VPN tunnel) only to send package to target servers (YouTube for example). And change the ...
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1answer
2k views

How to make connections answer from the same gateway they entered in RouterOS?

I have a MikroTik RouterOS 6.23 device, and my network is as follows: Router | |-- bridge1_LAN (wlan1 + ether1) (192.168.0.210) -- LAN (192.168.0.0/24) | Here is where computers are. Those ...
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2answers
175 views

iptables: static ephemeral port maps

I have a VPN on my Linux server which does IPv4 NAT, example: iptables -A FORWARD -m state --state RELATED,ESTABLISHED -j ACCEPT iptables -A FORWARD -s 10.8.0.0/24 -j ACCEPT iptables -t nat -A ...
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1answer
8k views

NAT doesnt work on CentOS 7(Firewalld)

I have configured nat to make my CentOS 7 into a router. I have used firewalld to do this. But unfortunately it doesnt work. I have no idea which causes the issue. I tried the same configuration in ...
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1answer
572 views

Possible for Socket communication between 2 internet-connected GSM modems?

I have 2 internet-connected 4G modems connected to 2 separate computers and I'd like to send/receive data between them with sockets (UDP) using the modems' packet-switched 4G Internet connection, not ...
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1answer
2k views

NAT Rule changes from ASA software 8.0 to 8.4

I have an Access Rule and a NAT rule that works fine with on the Security Appliance Software Version 8.0 The rule is as follows: However, I am having trouble making the same rule work on an ASA ...
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0answers
1k views

Set up pfSense on AWS VPC?

I am attempting to setup pfSense as a nat box for internal servers on a VPC. I have followed the guides posted for configuring access and have followed the AWS instructions for setting up and ...
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2answers
4k 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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0answers
329 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
323 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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1answer
108 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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195 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
77 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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1answer
73 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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1answer
866 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
48 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 ...