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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1answer
413 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
66 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 ...
1
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1answer
63 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 ...
1
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1answer
531 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 ...
1
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2answers
979 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 - ...
0
votes
1answer
161 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 ...
3
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2answers
497 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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3answers
3k 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 ...
0
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1answer
29 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
61 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 ...
0
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1answer
3k 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
115 views

iptables DNAT packets into an openswan IPSEC tunnel

I have the following network setup: +-----------------------------------+ | | ...
10
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3answers
14k 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 ...
0
votes
1answer
83 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
763 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
155 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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vote
2answers
159 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
votes
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
191 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
191 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
69 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
votes
1answer
301 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
58 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 ...
2
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0answers
79 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
616 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
118 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
287 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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0answers
331 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
217 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
206 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
237 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
109 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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0answers
73 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 ...
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0answers
71 views

NAT and DMZ Cisco ASR 1001

OHAI got weird situation on my two Cisco ASR 1001. First one is WAN router, the other one is CORE distribution inside the office. So I've got one public IP on my WAN, and got this particular line: ...
0
votes
1answer
3k 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 ...
3
votes
2answers
2k views

Service can't connect to self using public IP, NAT problem

I have a dedicated server from serverloft.eu, but due to some network security I cannot use bridge networking on my server. So I have setup all my IPs to the main eth0, and used NAT to forward trafic ...
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0answers
247 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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vote
1answer
349 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. ...
3
votes
5answers
384 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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votes
0answers
135 views

Change source IP for packet incoming in VPN tunnel

The following configuration allows me to change the source IP from 192.168.0.0/24 to 172.16.0.100 when hosts going to 10.0.0.100 and it works. But I can't achieve this goal for the hosts incoming from ...
9
votes
4answers
15k views

iptables nat does not exist

Today my iptables nat on the host system stopped working and I have no clue what happend! (That's very bad, I know) All commands are executed as root user. If I run $ iptables -t nat -L I get the ...
4
votes
1answer
244 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 ...
0
votes
1answer
165 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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vote
1answer
462 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 ...
2
votes
2answers
297 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
46 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 ...
2
votes
3answers
192 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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votes
0answers
108 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 ...
0
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0answers
532 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 ...
2
votes
2answers
352 views

Redirection with natd flags on FreeBSD

I am trying to setup a basic NAT server. I want all traffic coming from the outside world to the NAT server to be redirected to another machine, where I have a lipcap service running to parse this ...