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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VPN routed traffic, response goes outside of VPN?

Here's a weird one. Whenever I'm on a hotel network I tend to like to route all my traffic through my home network. Mainly since I'm not entirely sure all my passwords go through SSL all the time. ...
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2answers
173 views

NAT Masquerade to a L2TP/IPSec connection

I'm trying to create two networks (using a debian server) : The first one is intended to pass packets in a normal way (to my ISP). The second one is intended to pass packets via a L2TP/IPSec VPN ...
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1answer
331 views

Trouble with port 80 nating (XenServer to WebServer VM)

I have a rent server running XenServer 6.2 I only have 1 public IP so i did some NAT to redirect ports 22 and 80 to my WebServer VM. I have a problem with the port 80 redirection. When i use this ...
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0answers
141 views

How can I allow NAT from inside to outside and vise-versa when each of my clients will have only one static public IP using an ASA5525-X?

My network topology is pretty basic. My data center provides a router and added a switch just before my cage to provide connectivity to all of the racks. My rack takes the copper drop they provide and ...
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1answer
26 views

Need help configuring NAT

First of all, the router I am using is a Cisco WRVS4400N. My company runs a software which handles the MySQL database of all of their products. The software now has an e-commerce module, so I have ...
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0answers
35 views

Cisco ASA5505 Public IP Address

I am trying to configure a Cisco ASA5505. I am using the GUI start up wizard. When I assign the outside IP address to be a public IP address the configuration will work but after about 30 seconds the ...
0
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1answer
34 views

Iptables and counters

I'm trying to use iptables counters with munin to monitor traffic of hosts on my local subnet. For each host I set up a rule like this: iptables -I OUTPUT -d $ip This should count the packets going ...
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1answer
220 views

Configure clients to navigate through specific wan. Pfsense

I have a machine with a pfsense running. It is configured with three ethernet cards. LAN 192.168.2.1/21 WAN1 200.41.X.2/24 WAN2 200.41.X.3/24 ISP Gateway 200.41.X.1 This is a connection with 5 ...
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1answer
147 views

What is the correct iptables rule when NATing multiple private subnets?

I have a Centos minimal 6.5 acting as a router. eth0 is connected to a Cisco switch trunk port, allowing VLANs 200-213. I have several VLAN interfaces just as this link suggests: ...
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2answers
590 views

IPTables: NAT multiple IPs to one public IP

I'm looking for a way how to nat 2 or more inner IPs (in my case xen doms) to one outer IP. I tried to use iptables -t nat -A PREROUTING -d 123.123.123.123 -j DNAT --to 1.2.3.4 --to 1.2.3.7 ...
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1answer
1k views

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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1answer
211 views

One Public IP, Private IPs, DNS Server and Multiple Servers [closed]

I have lots of unanswered questions about these topics. So, lets begin. First off all, I'm not a server and networking guru. I'm a regular PHP developer. And I've read allmost all of the articles ...
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2answers
2k views

Cisco ASA - Configure External Access to a Server

I'm trying to configure my ASA (ASA 8.4(2), ASDM 6.4(5) ) to allow external access to a server (using RDP). I've tried everything, but it doesn't seem to be working. I'm sure it is something simple ...
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0answers
47 views

How to fix stalled connection on large download

I have a cisco 1921 router performing routing and NAT function. Cisco 3750 is performing layer 3 core switching duties. Users are complaining about large file transfers being stalled (not dropped) ...
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1answer
391 views

Cisco ASA Outside to Outside NAT (forward from one public ip to another public IP)

I have an ASA (A) with a set of public IPs (A1..A6). And I have another server S with a public IP (S1) . I want all traffic to A2:22 NATed (forwarded) to S1:22. (SSH is just an example here) If ...
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3answers
12k views

Public static ip for vagrant box

I have server (Debian Squeeze) with 1 ethernet card and 2 public static IPs (188.120.245.4 and 188.120.244.5). What I want: Setup virtual box (Ubuntu) with access via static IP (188.120.244.5). ...
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0answers
114 views

puppetlabs/firewall nat policy issue

I'm using puppetlabs/firewall. I need to create following iptable rules: iptables -A PREROUTING -p tcp -m tcp --dport 443 -j REDIRECT --to-ports 8443 My manifests is firewall { '001 default ...
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1answer
57 views

iptables: disable NAT except for only one client

I have a LTSP subnet (192.168.0.0/24) and want to disable NAT for every client except one client The purpose is to deny (on demand) access to internet from student clients, but always allow it from ...
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0answers
118 views

Cisco ASA 5505 Access Rules/NAT

I need to allow traffic from any IP to a specific port in an ASA 5505 using ASDM 7.1. I've already created an Access Rule to do this but I ran a Packet Tracer and it gets dropped due to an "implicit ...
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2answers
119 views

Iptables does not seem to be applying SNAT to packets sent on a raw socket

I'm sending packets from a user space program to my wireless interface wlan0. I've set up a SNAT rule with iptables as follows iptables -t nat -A POSTROUTING -o wlan0 -j SNAT --to 192.168.1.3 And ...
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1answer
151 views

Automatic updates for NAT instances and SSH connections in a AWS VPC with private subnets

My current website architecture has two Ubuntu servers with public IPs in Rackspace Cloud. One of them is web and mysql server. The other one is for time-consuming calculations only. Both of them ...
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0answers
735 views

Puppet agent (v3.0.1) hangs connecting to master (v3.1.1) in VM behind firewall (with NAT based access)

I am using puppet agent v3.0.1 (On FreeBSD), trying to connect to a puppet master v3.1.1 (On Ubuntu) and the puppet agent hangs with the following debug output: puppet agent --debug --no-daemonize ...
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2answers
861 views

Symmetric NAT and UDP Hole Punching

I've read this question, but the explanation of Symmetric NAT wasn't detailed enough. Please could someone help me to understand the following paragraphs? I read this about Symmetric NAT: Each ...
2
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1answer
228 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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2answers
12k views

how can I access a webserver running on my NATed VMware Fusion guest from the rest of the subnet? [closed]

I am not allowed to run my VMWare guest in bridged mode, and I want to somehow tunnel from an agreed port on the Mac's external network interface to the webserver running on the VMWare fusion guest. ...
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0answers
27 views

NAT with multiple connections

I have a linux server with 2 WAN connections. It has 2 public IP address as WAN_IP1 and WAN_IP2. The server default gateway is WAN_IP1. The server also has 2 LAN interfaces and the relative subnets. ...
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3answers
3k views

Does NAT change the source MAC address? [closed]

I'm trying to secure my home network but don't really need the complexity of a VPN so I'm trying to figure out other options. I'd like to allow my iPhone remote access to my home servers but I can't ...
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0answers
121 views

Cisco ASA 8.2, accessing an internal webserver with an external IP-address together with port translation

We have one web server, let's call it SERVER01. It is running two different web servers that both uses HTTPS, INTERNALAPP on port 443 and EXTERNALAPP on port 444. In a previous setup we had an old ...
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7answers
8k views

Loopback to forwarded Public IP address from local network - Hairpin NAT

This is a Canonical Question about Hairpin NAT (Loopback NAT). The generic form of this question is: We have a network with clients, a server, and a NAT Router. There is port forwarding on the ...
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134 views

unicast to multicast using Mikrotik

I'm looking for a way to do NAT on a mikrotik router so that a unicast stream received on one interface goes out another interface as Multicast. I've done this on Cisco before, but my company is ...
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133 views

iptables on router: why does nat prerouting not intercept packets?

There is a Debian Wheezy box with OpenVZ kernel (IP 1.1.1.1), working as router between Internet and VPS'es (IPs 1.1.1.100 and 1.1.1.200). Incoming packets addressed directly to VPS'es are normally ...
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0answers
110 views

ISC DHCP Server - Client Uplink Is Not Working

Running a DHCP server, client(s) does not have up-link (0Mbps) and has a downlink (50Mbps.) I am setting up a gateway/router on a PC running Debian Wheezy with ISC-DHCP. I have 1 WAN (eth0) and 2 LAN ...
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1answer
968 views

How to access server using public ip when in the network itself? [duplicate]

I've asked this question and even searched around but didn't get a useful answer for me. Basically what im doing is i have a webserver on internal ip 192.168.0.100 port 80. So if im in the network it ...
7
votes
2answers
273 views

FreeBSD's ng_nat stopping pass the packets periodically

I have FreeBSD router: #uname 9.1-STABLE FreeBSD 9.1-STABLE #0: Fri Jan 18 16:20:47 YEKT 2013 It's a powerful computer with a lot of memory #top -S last pid: 45076; load averages: 1.54, 1.46, ...
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2answers
647 views

Windows Server 2012 NAT Routing won't route clients from subnet (multiple external ips)

I obviously have some knowledge gaps in routing maybe you can help me: My ISP has given me 8 external IPs but I have to route them myself. The first IP is issued via DHCP and the other 7 are fixed. ...
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1answer
552 views

Does hole punching require a UDP rendezvous server Or could it be a TCP one?

I'm trying to get my head wrap around this issue... I would like to connect two users... Those users are already connected to a TCP server, which is aware of both public ip and connection TCP port. ...
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1answer
76 views

can anyone show me how can i fix error with my NAT config

Can anyone help me with my packet tracer problem? My network 2 buildings (each building has 3 vlans) on the same side and it has 2 sides, between is internet. I finish with DHCP and now I try to ...
4
votes
1answer
16k views

How are cellphone IP addresses assigned?

When my cellphone accesses a website via the tower and its GPRS gateway, NAT ensures that the sites receive a public IP. Would all phones using a single tower have the same IP? If yes, then how can ...
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votes
2answers
5k views

How do I forward/NAT all traffic to one interface/IP to a remote IP?

I have one "server A" that has multiple IPs attached to it, like so: eth0:0 1.1.1.1 eth0:1 1.1.1.2 eth0:2 1.1.1.3 I have another "server B" that also has multiple IPs attached to it, like so: ...
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votes
3answers
162 views

Packages drop when using iptables NAT

We are using NAT made with iptables. However when there are lots of connections (or sessions) through NAT server packages start to drop. There is no log in syslog etc. I think this is caused by sysctl ...
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0answers
320 views

Packets are not routed by iptables, how to debug

I'm using OpenStack and OVS. This is my case: From a remote host, I ping VM with IP A. Local gateway received the echo request, then send a packet with IP A and MAC address A' (based on a fixed ...
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0answers
68 views

Simple MASQUERADE NAT between 2 VM

I'm on a cloud service and I'm trying to set up NAT between two VM. I've never experienced issues in this simple step, but this time is different and I'm near to give up. The first VM had two ...
0
votes
1answer
2k views

Can't establish a reliable VPN tunnel (ShrewSoft client / ZyWALL USG-50 firewall)

I try to setup an IPSec VPN tunnel through my firewall (ZyWall USG-50), but it doesn't work like it should. quick scheme of my installation: ME [A.B.C.D] --- **INTERNET** | ...
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2answers
30 views

Does it seem from NAT when they really come through a proxy?

Just question. When a client really come through a proxy, can we tell it from being through NAT?
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6answers
360 views

Does connecting to the default host via public IP from within its subnet cause any issues?

I'm setting up a small office network with a single public IP (let's say it's 69.16.230.117). I've configured NAT on the router with incoming traffic forwarded to the server (say the server has a ...
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2answers
86 views

Assign internal IP address based on subdomain

I have a domain name, let's say foo.com. I have a server which has a public IP (Server-A). I also have a lot of servers (Server-B, Server-C, Server-D etc) which are all connected in a private network ...
0
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0answers
128 views

Cisco ASA Access anyconnect from inside IPsec tunnel

I have a Cisco ASA on a dynamic WAN IP with a IPsec site-to-site tunnel to a remote linux host in a datacenter with a static WAN IP. All non local traffic is tunneled and the datacenter end is the ...
0
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0answers
260 views

Cisco ASA 5505: PAT / NAT between 2 IPSec Tunnels

I've the following Setup: Customer <-> HQ <-> Branchoffice The Customer has a 192.168.1.0/24 subnet. On the HQ only the VPN Gateway is in my context, 172.20.10.1 . And on the Branchoffice ...
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0answers
128 views

Linux routing: How to allow a device inside private network to connect a public IP over an unknown network?

Consider following network topology: ---------- ---- (my network) ---- | Device 1 | (.101) | 192.168.191.0/24 | ---------- | | ...
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1answer
1k views

Port Forwarding on Cisco Router

I'm a Cisco newbie, have the 1841, with two ethernet interfaces: interface FastEthernet0/0: Internal Desired destination IP: 186.67.181.140 interface FastEthernet0/1: External World IP ...