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.

learn more… | top users | synonyms

1
vote
1answer
62 views

Websever behind Sonicwall, Gateway Timeout

I am stuck here, I have a Cradlepoint CBA750B in IP-passthrough mode connected to x1 on my Sonicwall NSA220. Behind the Sonicwall I have a webserver on the LAN. I have X1 set to use DHCP to get the ...
0
votes
1answer
410 views

How accessing a NATed, virtualized (LXC) server over public IP from client itself on a bridged network?

Setup ____________________________ ____________________________ | Host | | Client | | Public IP: 66.66.66.66 | ...
1
vote
2answers
200 views

Configure VirtualBox webserver to see visitors IP address

I finally managed to move my server to VirtualBox virtual machine. VM is running in NAT mode. I have forwarded necessary ports, including the port 80 which I first fowarded with iptables to port ...
1
vote
1answer
100 views

Redirect traffic from one server to something.cloudapp.net (CNAME) [closed]

Through out North America, we have lots of legacy devices, which sends data to our server which has static IP Address. Now we are moving to Azure cloud services, and as you know they do not guarantee ...
0
votes
0answers
592 views

Cisco 881 losing NAT NVI translation config after reload

This is a weird one, so I'll try to explain in as much detail as I can so I'm giving the whole picture. As I've mentioned in my other questions, I'm in the process of setting up a new Cisco 881 as my ...
1
vote
1answer
780 views

Reverse NAT Setup for Hyper-V on Win 2008 R2

I'm trying to setup a Linux server behind a Windows Hyper-V host that will help supply some of the services (SSH, HTTPS, etc). However getting RRAS configured for reverse NAT (port forwarding) turned ...
0
votes
1answer
119 views

CISCO: conditional port-based NAT (policy-based PAT)?

I have a problem to nat-translate inbound http packets to different local_ips based on some condition (like dscp bits set). Actually the dscp bits get set on the incoming trafic using NBAR. I hope ...
1
vote
0answers
93 views

Firewall and NAT settings in GSM modem for one server

I have a GSM Modem (PSI-MODEM-GSM/ETH) in field with one device behind, acting as a server. The situation is as follows: "PC" | \_________Dynamic IP: 10.103.153.122 | ...
1
vote
2answers
88 views

Communicating between two servers sitting behind their respective NATs

I'm building an web app (Server A) that communicates with a remote server (Server B) that is connected to the internet. Server B resides behind a NAT and is listening to communication on 3 ...
3
votes
3answers
3k views

Advanced routing problem

I have 2 internet links using 2 ADSL routers and I need to give access to the Internet for the 192.168.0.0/24 network. I have to route outgoing traffic based on port number, protocol, … using ...
-1
votes
1answer
115 views

iptables NAT table not matching anything [duplicate]

I am attempting to take a TCP service running on port 1234, and make it appear as if it's running on port 81. I thought the following might do it: iptables -A PREROUTING -t nat -p tcp --dport 81 -j ...
2
votes
3answers
1k views

Iptables massive 1:1 NAT

I have to connect two LANs: LAN1: 10.10.0.0/16 and LAN2: 192.168.0.0/16. I can't do simple routing, because 192.168.0.0/16 net is prohibited in LAN1, so I am thinking of using Full cone nat (1:1) to ...
0
votes
1answer
56 views

Software for emulating networks and NAT

I am working on a software that I need to test with different types of NAT, and I would like to set up a test environment I can reconfigure in different NAT modes. I would like to have: ...
0
votes
1answer
51 views

How to avoid hairpin VPN on cisco

I currently have a hairpin VPN setup with a Cisco ASA, but I'm not very happy as it messes up service access that are on ASA external IP address and are NAT'ed inwards :( How should I re-design the ...
0
votes
1answer
53 views

iptables NAT forward range

I have two network interfaces, eth0 and eth1. eth0 has a public ip, eth1 has 172.16.0.254/24. I'd like to do the following mapping: 172.16.0.1:22 -> eth0's public ip:2001 172.16.0.2:22 -> ...
0
votes
1answer
136 views

Iptables/ufw - blocking ports when using nat

I use NAT to move requests from external ports to an internal ip address and port hosted with proxmox. Something like this: iptables -t nat -A PREROUTING -i vmbr0 -p tcp --dport 8000 -j DNAT --to ...
0
votes
0answers
28 views

Is it possible to hairpin on Cisco 851W IOS 12.4(15)T9 and how?

I need machines on the LAN to be able to access by the external address or hostname. If it can't be done, then just by hostname is OK as well, so I thought of just doing it through DNS on our internal ...
8
votes
3answers
15k views

Load balancing & NAT-ing multiple ISP connections on Linux

I have two internet connections from two different ISPs and I need to balance the traffic originating to and from my network between the two ISPs. I am using Debian GNU/Linux. My set-up is like this ...
0
votes
1answer
409 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 ...
3
votes
2answers
5k views

Inbound SIP calls through Cisco 881 NAT hang up after a few seconds

I've recently moved to a Cisco 881 router for my WAN link. I was previously using a Cisco Linksys WAG320N as my modem/router/WiFi AP/NAT firewall. The WAG320N is now running in bridged mode, so it's ...
0
votes
1answer
146 views

access same subnet on different interfaces

I have a router with external (WAN connection) subnet 192.168.1.0/24 and also on same router a tunnel to a remote location which have the exact same subnet (192.168.1.0/24), and i need from my LAN to ...
3
votes
2answers
878 views

Can explicitly ftps via Filezilla but not from code

This was originally posted to StackOverflow, but because the code works and this is most likely a network/firewall issue, I figured I'd ask it here. As the title states, I can connect to another ...
0
votes
0answers
97 views

FTP Traffic routing through NAT prevents me from logging in

I need to send all FTP traffic to a particular server from a NAT. Server A connects via FTP to an IP which is routed to the NAT and then over a VPN. That traffic then comes back and gets routed from ...
3
votes
3answers
495 views

How can private IPV4 addresses get past iptables NAT (tcp RST,FIN)

I've got a router performing simple NAT translation using iptables iptables -t nat -o -j MASQUERADE This works fine almost all of the time except for one particular case where some TCP RST and FIN ...
1
vote
0answers
73 views

strongswan packet get natted when ufw is enabled

I'm using strongswan 4.6.4 to connect road warriors to my server (ubuntu 13.10), which is natted behind a firewall. left=%defaultroute leftsubnet=10.10.1.0/24 right=%any ...
-2
votes
1answer
146 views

Dead-simple Juniper firewall hairpinning [closed]

I have a SRX100 firewall running JunOS 12.1. I have a WAN interface proxy ARPing ten or so static routable IPs. I have a LAN interface on a simple class-C subnet (we'll call it 192.168.0.x). I'm using ...
1
vote
0answers
52 views

OpenVPN running on Internet Gateway, so all private clients can access VPN with no config

Our LAN connects to our office gateway machine (192.168.1.1), which is connected to the Internet. I have setup NAT/Masquerading for this purpose with no issue. We also use OpenVPN to connect to our ...
0
votes
0answers
44 views

Cisco IOS log packets dropped due to no NAT entries?

I use access list logging currently, and update the access list to match the NAT table, and then the access-list deny any any log command is used for logging packets that were not allowed. However, I ...
2
votes
2answers
189 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 ...
1
vote
1answer
142 views

Access Apache VirtualHost from localhost

I have a DirectAdmin setup with Apache on a server which is behind NAT. Everything is working correctly when accessing a VirtualHost from outside the machine (either through the Internet and the ...
2
votes
1answer
43 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 ...
1
vote
1answer
133 views

how to forward proxy requests using iptables

I've this schenario ----------------- ---------------- ---------- | SERVER A | ---(port:2128)> | PROXY | ---> | INTERNET | | (10.30.1.1) | ...
1
vote
1answer
2k views

Asterisk and SIP behind NAT

I am trying to Setup an Asterisk-Server to accept calls from a client in an other Network. The Server and the client are behind an NAT. I have already activated STUN on the client, but I am still ...
0
votes
1answer
70 views

Cisco ASA 5510 nat

In my infrastructure, I natted a server on a Public IP address. Please note, the server is reachable from any outside network. My access rules are good. My isssue is from the internal network, I'm ...
0
votes
2answers
171 views

Portforwarding with IPTABLES and Remote IP detection

I was able to forward 80 port from my primary server 192.168.90.1 to the second one 192.168.90.2 with IPTABLES The primary server has a public address X.X.X.X so I forwarded X.X.X.X:80 -> ...
0
votes
1answer
449 views

How to NAT behind public IP on pFsense before IPSEC to Cisco ASA?

I have two networks: Local 192.168.1.0/24 and Remote 10.8.8.8/24. On the local network I have installed pFsense as gateway. On the remote network there is a Cisco ASA that I don't have control over. ...
0
votes
2answers
38 views

Forwarding all connections to different address

I have a script that tries to connect to rabbitmq using default url and port (localhost:5672). Is it possible to make linux redirect all connections to this url and port to different server? I am ...
0
votes
2answers
109 views

Forward web request to another computer

I have one notebook and two servers: ip = 172.17.0.2 (I have installed nginx here) ip = 172.17.0.3 (There is nothing here, but I can ping 172.17.0.2 from here) I open browser on my notebook, open ...
0
votes
1answer
1k views

strongSwan setup where both sides are behind NAT

I'm trying to setup a strongSwan server in my home and connect to it from another network. Let's say sun is the VPN server and venus is the client. Both sun and venus are behind NAT networks. sun is ...
1
vote
1answer
190 views

Linux iptables DNAT stops working after some time

3 down vote favorite I have a strange behaviour in my server setup. It looks like that. client1 192.168.11.2/24 <----> 192.168.11.7/24 (br1/vlan1) Server 192.168.21.1/24 (br21/vlan21) <---> ...
0
votes
1answer
96 views

How do I know that my TCP connection is safe from the Firewalls/NAT?

Being on the Azure cloud, I found that the firewalls there drop connections between the Web server and the database quite often. Mostly when there was some inactivity, I think something between 5 and ...
0
votes
1answer
132 views

How to apply port forwarding with iptables on existing connections?

For load balancing purposes, occasionally our servers forward requests to a different port; The default port for our service is port 5000. This is the code used: iptables -t nat -A PREROUTING -p tcp ...
0
votes
1answer
168 views

Configure atftp server to reply on port 69

Problem : I'm facing to a problem with TFTP server and Cisco 79XX IP phones. When on a local network, everything is working fine, but when the TFTP server is on a public server (and phones inside a ...
0
votes
0answers
18 views

client does not respond server's syn_ack package

pc to access the server through a NAT device。 client has successfully established a tcp socket with server using this port , and the server's interacted with the message well, socket has been closed ...
1
vote
1answer
265 views

How can I know if NAT instance is becoming a bottleneck

I'm running my own NAT instance inside of an AWS VPC. I want to make sure that the NAT instance will not be a bottleneck and to that end would like to set my own expectation for when to scale to a ...
1
vote
0answers
141 views

Simulating a client behind a NAT in Virtual Box

I am trying to simulate a client behind a NAT using Virtual Box. I have a host machine let's say with an IP address 130.0.0.1. I create a virtual machine (let's call it VM1) running Ubuntu 12.04 with ...
0
votes
0answers
137 views

Load-balancing PPTP connections

I'm trying to load balance two PPTP connections, connected to the same server. I use the following script, but there is no send and receive via PPTP connections. What part am I doing wrong? Are there ...
-2
votes
2answers
170 views

Iptables MASQUERADE: What is the advantage/disadvantage between these two commands? [closed]

What is the advantage/disadvantage between below 2 commands: iptables -t nat -A POSTROUTING -o eth0 -s 10.0.0.0/16 -j MASQUERADE AND iptables -t nat -A POSTROUTING -j MASQUERADE Some Background ...
1
vote
2answers
2k views

AWS VPC + IPtables + NAT: Port Forwarding is not working

Yesterday, I posted a question here but I think was not clear enough in my words. BTW, This question is not a duplicate. I have AWS VPC Setup as below. GOAL/PROBLEM: SSH to Server A from internet. ...
1
vote
1answer
241 views

iptables DNAT port forward to another machine on LAN

I am trying to implement iptables forwarding rules in order to internally redirect packets coming through a specific port. My machine is running under the distribution Ubuntu Server 12.04.3, with UFW ...