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 routing don't pass packets [on hold]

I have a win server 2008r2 with routing and remote access role wan interface 54.93.71.23 domain.com lan interface 172.16.0.0 From internal network i can access to www except our domain.com Router ...
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1answer
15 views

How to connect to P2P clients behind a router?

Apologies if this question has been asked before, but I don't think any of the ones I've found are asking quite the same thing. I'm designing a simple P2P protocol whereby a known server provides ...
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1answer
22 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, ...
3
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3answers
798 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 ...
3
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1answer
321 views

Authorative DNS behind NAT possible?

I am currently running an authorative Bind9 DNS server for a bunch of domains. This authorative server currently replicates to a couple of slaves which are then used to meet the subnet requirement for ...
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0answers
9 views

SNMP through NAT when server has two IP addresses

We have an SNMP client talking to an SNMP agent through NAT. That works most of the time. We send an SNMP request e.g. from 1.2.3.4:12345 to 10.0.0.1:161 and get a reply from 10.0.0.1:161 to ...
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4 views

How to enable ping between machines connected in two interfaces? [migrated]

I have a linux board with two ethernet interfaces as mentioned below. eth0 connected to another linux machine (ad-hoc) eth0 on board 191.168.1.2 connected to Linux machine 192.168.1.3 eth1 on board ...
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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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3answers
2k views

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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1answer
41 views

Using host's iptables to prevent access to docker-container's exposed ports

I have a host which runs a few docker's containers. This host has a few network interfaces, my goal is make some exposed ports from containers accessible only by certain interfaces, and prevent ...
2
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2answers
1k views

Iptables: Forwarding packets doesn't work

I have 3 Linux Systems A, B and C. A is a TCP Client and sends a message to TCP Server on C. A can see only the external IP of B which is at wlan0 interface, 192.168.0.3 ------------------ ...
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2answers
837 views

OpenVPN AS accept connections forwarded by NAT

We're running OpenVPN AS servers which are accessable and working over a public IP. But some of our clients aren't allowed to access our VPN server directly (because of some nasty firewall admin - ...
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1answer
30 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
278 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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1answer
1k views

How to make sysctl network bridge settings persist after a reboot?

I am setting up a notebook for software demo purpose. The machine has 8GB RAM, a Core i7 Intel CPU, a 128GB SSD, and runs Ubuntu 12.04 LTS 64bit. The notebook is used as a KVM host and runs a few KVM ...
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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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3answers
2k views

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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1answer
20 views

Howto forward traffic between multiple OpenVPNs

I have an OpenVPN server which hosts two VPN networks, one is bridged and the other one is routed. See the following draft: The VPNs are working quite well while they are used in isolation. But if ...
0
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1answer
23 views

ip6tables snat don't work properly [closed]

I got three computers with these names: laptop, vds and home; vds is openvpn server; home is openvpn client. and, I got an ipv6 network 2a01:dead:beef::/64 vds has address 2a01:dead:beef::311 on ...
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1answer
63 views

MikroTik - can't access webfig from external / can't SSH into router from external ip

Ok, here's the deal. Let's say that my public facing IP is 10.0.01. I can't webfig into 10.0.01 from external and can't SSH into mikrotik router from external IP. I can do it if I am physically ...
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0answers
4 views

Behind ISP NAT Firewall - Need to remotely monitor CCTV's [migrated]

Here's my situation: I have a DVR which is capable of allowing me to remotely view my shop CCTV's over IP.However, I'm behind the ISP's NAT firwall and have no ability to open ports on the router, so ...
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32 views

iptables DNAT packets into an openswan IPSEC tunnel

I have the following network setup: +-----------------------------------+ | | ...
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2answers
2k views

cisco ip nat / port forwarding

I have been trying to get port forwarding working with a newly installed cisco router. I cannot seem to find where my fault is and have been looking for quite a while. The relevant section of my ...
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1answer
1k views

iptables forwarding through virtual interfaces

I'm trying to configure my computer as a gateway between two networks, but I cannot make it working for some reasons Here is a representation of the network: 192.168.1.101 192.168.1.102 ...
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3answers
10k views

How to configure a custom NAT for use in Amazon VPC

I have an Ubuntu box I wish to use as NAT instance (among other things). I would prefer to avoid using the NAT AMIs provided by Amazon, and instead configuring NAT myself. Currently, my host has a ...
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1answer
39 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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60 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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0answers
42 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 ...
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1answer
2k views

iptables forward rule not working in openwrt

I am trying to apply some iptables forwarding rules in openwrt. Here is my scenario - My server has two cards ath0 and br-lan. br-lan is connected to internet and ath0 to private network. The other ...
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2answers
56 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 ...
5
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2answers
1k views

TomatoUSB multiple IPs not forwarding

I am trying to use this Guide to enable multiple IPs on TomatoUSB. Our Firewall rules need to NAT and allow a 1to1 to two servers. /usr/sbin/ip addr add 208.x.x.133/30 dev vlan1 /usr/sbin/ip addr ...
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2answers
1k views

Unable to PPTP through NAT on Cisco 881

I'm trying to connect to a PPTP server which is sat behind a Cisco 881 NAT router. The server is running Ubuntu Server 12.04 and is running Poptop pptpd as the PPTP daemon listening for connections. ...
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2answers
32 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 ...
0
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2answers
51 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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0answers
34 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 ...
0
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1answer
172 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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0answers
11 views

DD-WRT: Remote SSH access doesn't work when OpenVPN client is enabled [migrated]

Problem description I have a DD-WRT router which I would like access remotely via SSH. The DD-WRT is behind an ADSL router which has port forwarding for port 22 enabled, DD-WRT SSH access and service ...
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1answer
116 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 ...
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1answer
864 views

how to setup sonicwall tz210 to port forward packets received from external ip to another external ip

i have a sonicwall tz210 on a fixed ip, say ip1. And then i have, let's say a legacy server, with external ip ip2, which sends data to ip1 (and I have another server on ip1 behind the sonicwall which ...
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0answers
19 views

L2TP daemon server multiple IP

I have VPS with 3 public IP - Debian 7. I would like to have 3 L2TP damemons (one ip each) NATing traffic to each ip. Something like this l2tp_multiple_public_ip_diagram. I have set up l2tp daemon for ...
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0answers
73 views

Change sender-IP for VM in libvirt behind NAT

I have a server with my own public /28 IPv4 Network. On this server I have some vServers, done with KVM/libvirt. These vServers are connected with a virtual network, NATed to the internet. Every ...
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0answers
549 views

Route two public (ISP assigned) subnets on 'outside' interface of Cisco ASA 5510

We've got a Cisco ASA 5510 that sits on our edge and acts as the PPPoE endpoint for a fibre connection. The fibre connection came with a static IP, which is assigned via PPPoE, and gets picked up by ...
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2answers
51 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
87 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 ...
0
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0answers
73 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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0answers
37 views

iptables, outside and inside NAT; Return traffic going out incorrect gateway

Overview (TL;DR at bottom) I have a third party firewall/proxy appliance which is running Linux (Ubuntu), and its routing and firewall engine is backed by iptables and the Linux (source)routing ...
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2answers
186 views

Do I need public DNS records for the external IPs of our workstation NAT?

We have certain stakeholders who believe that the public IPs used by our workstations should have globally available DNS records, and that not having dns records would break some internet services. ...
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0answers
60 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
40 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 ...
0
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0answers
35 views

NAT and S2S VPN to Azure issue

I can connect to the VNet with on-premise WS2012 R2 RRAS S2S VPN connection successfully. The on-premise WS2012 R2 has two NICs, "External" and "Internal". "External" NIC is facing to a public IP ...