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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How to forward host ports of < 1024 to a VirtualBox NAT-connected machine?

The manual says: "Forwarding host ports < 1024 impossible: On Unix-based hosts (e.g. Linux, Solaris, Mac OS X) it is not possible to bind to ports below 1024 from applications that are not run by ...
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993 views

asterisk/freeswitch in nat/no-nat setup

my current setup - i use bunch of sip hard-phones around few offices. all devices have two sip accounts configured - one on internal sip proxy [for calls between the branches], another - at 3rd party ...
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2answers
3k views

How do you implement NAT-T passthrough on a Juniper SRX series Firewall?

We have 3 juniper SRX-100 firewalls, they are configured like so: FW1 -> FW2 -> INTERNET -> FW3 We would like to create an IPSEC tunnel between FW3 and FW1 passing through FW2 preferably using ...
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328 views

Potential double NAT problems in an OS X office

We have a Comcast SMC Business Gateway router/modem combo in our office, and it doesn't provide much in the way of diagnostic tools or QoS routing. I want to plug another router with Tomato installed ...
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Route-Map vs ACL for Cisco NAT

Is there pros and cons of using route-maps vs access-lists for network address translation on a cisco router?
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NAT GRE (IP protocol 47) over Linux router

I have a host that has a permanent static GRE tunnel to a server on the Internet. Right now the host has its own real IP address. I want to put the host behind a Linux box (Smoothwall), and assign it ...
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2answers
52 views

Exposing private network ip

I have the following setup: Box A eth0 - 192.168.1.101 eth1 - 10.10.2.1 Box B eth0 - 10.10.2.2 Box A has internet access through eth0. I want Box B to be visible on the 192.168.1.0/24 network, so ...
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Proxmox Nat Networking Issue

Definition I have installed Proxmox 3.2 and i am trying to configure a virtual machine as a communication server that handles all traffic and forwards them to the nodes with private ip. I ...
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92 views

Routing DHCP traffic over the internet

i'd like to know if it's possible for the internet to be between a DHCP server and the network it's "assigned" to? so basically, something like this: -------------- ------------- ...
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1answer
3k views

Routing between 2 different subnets on 2 different interfaces in SonicOS

I'm having a bit of a problem allowing traffic between two of my subnets. Here's the structure I've built. The X0 interface has our windows server on it and it handles DHCP/DNS, etc. X1 has the WAN ...
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124 views

Can I use NAT64 to route public IPV6 traffic to internal IPV4?

I have a bunch of public IPv6 addresses and some services that run IPv4 only. Can I use NAT64 to connect these services? Is there another solution like a proxy or something?
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66 views

Should we accomodate a customer asking us to NAT servers behind new PUBLIC IPs within a VPN?

We're a SaaS provider, setting up a IPSec VPN between our data center and a customer's site so they can directly access their hosted database server from their LAN. Instead of exposing our internal ...
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libvirt and network filtering with nat - iptables overrides

At first, I want to say: I know, it was done initially wrong and I want to avoid doing everything again from the scratch because of general downtime. I am running libvirt/KVM on RHEL. I've got VM ...
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How to set mark on packet when forwarding it in nat prerouting table?

I have a few port forward rules like this iptables -t nat -A PREROUTING -p tcp --dport 46000 -j DNAT --to-destination 172.16.8.2:46000 iptables -A FORWARD -p tcp -d 172.16.8.2 --dport 46000 -j ACCEPT ...
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449 views

can't find a way to forward in iptables for specific mac address

I use a linux Centos 6.3 as an Internet gateway with NAT. I want to allow a specific host to have access to Internet, but I don't want to use its IP address since it may get a new IP address from the ...
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100 views

Special Routing and NAT requirement

I have a rather special routing and NAT issue which I hope I can fix somehow. Inside my company we run a supernet like 192.168.0.0/21 (192.168.0.1 - 192.168.7.254) All computers have this subnet mask, ...
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106 views

Multiple VMs under VBox, NAT mode, are not responding network requests

I am learning about virtualization. I have been managing real Linux servers for some time but this is the very first time I virtualize, so sorry if I am missing something. My setup is like a ...
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724 views

Forwarding MySQL connection with iptables and differents network interfaces

I have a PC with Ubuntu as a router. It has a 3G connection with a public IP to the Internet, and there is a private wireless subnet. So it has two active interfaces: ppp0: public IP (WAN) wlan0: ...
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112 views

Port Routing between different domains

i have a apache server located on a.com:9254 I would like to route a.y.com:80 to a.com:9254. So, I can put all my services under y.com domain. I tried proxy. However, In apache, it looks all ...
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1answer
144 views

Forward port on same machine?

I'm trying to forward an existing port for an application which can only listen on one port. The problem is the program and the firewall is on the same computer (Windows Server 2008 R2). For ...
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3answers
222 views

ASA: How to connect server with a external IP address already assigned?

Any ideas how this can be done on a ASA? There was a sonicwall in place but it just died and we do not have a replacement besides this ASA. The 24.172.x.132 is a spam filter and I can't change the ...
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Issue NATing server private interface to loopback (for MySQL)

I'm trying to NAT traffic sent to the server's private interface to the loopback (because MySQL bind-address is on 127.0.0.1 and can't be changed but I still need to reach it via the private ...
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kvm, can't access guest from outside host

following ubuntu guide on kvm, I've a test server up and running at this ip address 192.168.0.210 (netmask 255.255.255.0). The virtual machine (same as host ubuntu 11 server) use dhcp but has a ...
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iptables and DNAT. quick question

So I have a machine with a single interface. It has 2 ip addresses (eth0: 192.168.2.3, eth0:1 192.168.2.4). I'd like to take any traffic coming in on 192.168.2.4 and NAT it to an external ip ...
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SNAT through Racoon IPSec VPN

I am trying to route traffic from a device (that I will call "target") connected to my Ubuntu box (that I will call "host") to servers at a remote office. The host uses a Racoon IPSec VPN, connected ...
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How Does VPN Passthrough Actually Work?

I am interested in PPTP passthrough here not Ipsec etc. I have looked on the net but can't find out how it is done. I am an IT administrator myself and know a lot routing, NAT etc. I think I know how ...
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2answers
696 views

Assigning many WAN IPs to a Linux Router for 1:1 NAT?

I'm in the process of setting up an Ubuntu Linux box to act as a router. Its a fairly normal setup with NATing using IPTables - and its working fine for me. I'm about to put this into production, and ...
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1answer
379 views

Cisco Small Business: Classless routing vs Classful routing / Class A vs Class C?

Hypothetical topology: Cisco supports the diagram on the left as it relates to the Cisco Small Business WRVS4400N Router. As in, both sides of the WRVS4400N are 192.168.1.*, and the routing is ...
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Cisco ASA 5505 DMZ Setup Issue

I have an ASA 5505 running v8.4. I have one static IP that my ISP gives me and I need to use that for my INSIDE network as well as my DMZ. This becomes a PAT issue as I need some ports to terminate ...
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3answers
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Openvpn not routing to the internet over a tun interface

I've set up openvpn using tun. I can ping both ways between client & server. But I can't ping from the client to 8.8.4.4 (as a test). I've added nat with: iptables -t nat -A POSTROUTING -o eth0 ...
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Exposing multiple virtual machines to public Internet from laptop on any connection

I've got a couple of Ubuntu virtual servers on my laptop that I drag around with me and use to test configuration and interaction of services like mail, directories, etc. I therefore want to make them ...
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991 views

vmware nat internet connection

Host: Windows Server 2008 / VMWare Server 2 Has Internet connection ip: 172.17.62.1 (NAT adapter) no gateway, no dns Guest: Windows Server 2003 ip: 172.17.62.2 (NAT) gateway 172.17.62.5 (set in ...
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657 views

Some HTTPS connections via NAT fail, but work on firewall itself

I am having trouble establishing some HTTPS connections from internal machines, even though these same connections work if initiated on the firewall itself. The firewall machine is running Ubuntu ...
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2answers
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iptables nat: Handle OUTPUT chain via PREROUTING chain / forward from OUTPUT to PREROUTING

I would like to automatically handle packets in the OUTPUT chain of the NAT table (which are generated locally) like if they come from outside (via PREROUTING). Is is possible to use a "forward ...
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1answer
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Address (url) forwarding with Vyatta

Got this kind of noob question i suppose. I got this very basic network setup and need help to set up some address forwarding. As seen in my illustration below all traffic enters via the eth0 ...
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3answers
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PPTP pass through on Cisco ASA 5505 (8.2)

Is it possible to setup PPTP VPN traffic (clients outside and server inside) to passthrough a Cisco ASA 5505 if the outside IP address is also being used for PAT? The Cisco examples forward all NAT ...
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605 views

NAT: Exposing SQL Server 2008 Express to the internet

I have a Windows Server 2003 SP2 machine with SQL Server 2008 Express installed. I have my network configured with a NAT. Internal clients can access the instance of SQL Server without a problem. I ...
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Unable to ping or access internet

I am setting up a private network. The server is Windows 2008 R2 with DNS installed and has a fixed external IP address. ipconfig outputs the following: PPP adapter RAS (Dial In) Interface: ...
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1answer
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Iptables and SNAT

I am a newbie to iptables with NAT. My network setup is as shown below linuxbox2 (192.x.y.a) | (194.160.1.1) | linuxbox1(eth1)-------- Switch ...
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2answers
952 views

SIP and NAT routers?

SIP was not built with NAT routers in mind, and I'd like to get to the bottom of this issue to check what needs to be done on all devices so it works with NAT routers, and understand in what context ...
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4answers
483 views

JUNOS firewall issues

I am in the process of trying to setup a Juniper SRX240. I have been using the screenOS firewalls for sometime and having some difficulty adjusting.I haven't quickly been able to find a way to do in ...
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2answers
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How do you have NAT always assign the same IP address in VMWare Fusion?

I currently have 4 virtual machines I've created using out-of-the-box VMWare Fusion on my MacBook Pro. They are all configured with NAT for the networking and therefore get a 192.168.43.xxx IP ...
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160 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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137 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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129 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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273 views

pfSense Cluster not working with Manual NAT

I have two pfSense clusters, one is 2.1.4 and one is 2.1.3. The directions suggest that Manual Outbound NAT is required, but the 2.1.3 cluster is working just fine using Automatic NAT, servers and ...
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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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[SOLVED ]Openvpn routing for lan to lan through tun

I am trying to setup an OpenVPN tun to connect two lan's The open vpn connection is up and working but there is a problem with my routing or nat or something. What I need is an example of what a ...
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2answers
734 views

Internet VPN Tunnel with a server behind NAT

Let's say someone would like to route all their traffic traffic though some PC in another country (to unblock some sites). However, this PC is a usual Windows 7 PC behind a router with NAT, which ...
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2answers
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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 ...