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
501 views

Can you configure SNAT with multiple source IP's and use static DNAT (port forwarding)?

We have a private LAN connected to a firewall with multiple public IP's to use for SNAT in order not to overload the ports on a single IP. However, we have a requirement to allow certain workstations ...
-1
votes
3answers
75 views

Set static IP to a server behind the NAT [closed]

In my company, we just bought a server and now we want to set a static IP to it. Well, I've contacted my ISP and they said that they can give me static IP. So far, so good. My question is, where ...
17
votes
7answers
2k views

Why don't more organizations use inside-to-inside NAT or similar solutions to allow NAT hairpins?

Inside-to-inside NAT aka NAT loopback solves hairpin NAT issues when accessing a web server on the external interface of an ASA or similar device from computers on the internal interface. This ...
1
vote
1answer
27 views

destinantion-based NAT cisco routers

On a Cisco Router I need to translate "NAT" the LAN IP of some PCs based on the destination e.g. Connecting to 172.16.0.0 /24 Transalte to 172.16.0.100 Connecting to 0.0.0.0 0.0.0.0 Translate to ...
1
vote
1answer
2k views

How can I NAT traffic for one VPN to come from a different IP on Cisco ASA?

I have a Cisco ASA firewall between our private network (10.1.0.0/16) and the outside world, and multiple VPNS going to client sites. Existing: [10.1.0.2...] = source client | [10.1.0.1 ASA ...
-2
votes
2answers
85 views

Do I need 2 NIC cards to forward public IP to private IP? [closed]

To use NAT do I need 2 nic cards? I want to use my server for my own business (I don't require VPN) and simply need to forward my public IP to the private IP so that websites show up as ...
1
vote
0answers
626 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 ...
0
votes
1answer
1k views

pfense needs to be rebooted to effect a change in existing NAT

Using PFSense ver:2.0-RC1 (i386) When changing an existing NAT rule in pfsense I find that the rule doesn't work when: 1. the rule existed but with a change to its port number or destination LAN ip ...
7
votes
2answers
238 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, ...
6
votes
1answer
357 views

How do I configure NAT rules when using ASA IP-SLA when leveraging post-ASA-8.3 NAT syntax?

We are currently running ASA9 at a location with redundant ip connectivity. We'd love to configure ip sla so that internet access survives a single carrier outage. I'm aware of the ip sla commands, ...
0
votes
0answers
157 views

set DMZ server on modem that not support DMZ, using port forwarding

I have to see an application server from outside of my network, but the modem that I am using is a Zyxel P-660-HN-T1H that not supports DMZ server configuration.So, which port(s) I should forward to ...
0
votes
2answers
608 views

DSL routing - NAT Virtual server - port forwarding - static ip address [closed]

My NAT virtual server - port forwarding has been working fine up to the past couple of weeks. All in a sudden, it doesn't work. Setting was done as shown on the link: I'm afraid it no longer ...
1
vote
0answers
504 views

NAT Pooling with IPSEC source int on Fortinet 60c

I've been working on this one for a while, and been trying to figgure it out but now I've been banging my head against the wall.. We have the following setup: Fortinet 60c configured with these ...
1
vote
1answer
2k views

install iptables_nat module on centos 6.4 [duplicate]

I am trying to add the following rule: iptables -t nat -A PREROUTING -p tcp -m tcp --dport 80 -j REDIRECT --to-ports 8080 but what I am getting is: FATAL: Module ip_tables not found. iptables ...
1
vote
1answer
290 views

Redirect traffic on port 80 into apache for unknown macs, and into squid for some macs

I have a linux box behaving like a router that handles two network interfaces: eth0 for internet and eth1 for LAN. I set up iptables in order to redirect all the web traffic coming by the LAN into a ...
1
vote
1answer
389 views

Provide public access to a local web server through VPN

I have a VPN tunnel established between 2 servers: VPS-A and VPS-B having the (fictional) public IP addresses: 66.55.44.33 and 77.88.55.66, and VPN endpoints 10.0.1.1 and 10.0.2.1 respectively. There ...
1
vote
1answer
351 views

iptables can drop traffic but cannot redirect

Suppose that TCP packets are sent to destination ip (dest_ip) and can be dropped by the following command: iptables -A INPUT -d dest_ip -p tcp -j DROP But when I try to redirect the packet using ...
0
votes
1answer
775 views

How to send HTTP request issued by cURL through VPN?

Please excuse me for (probably) the noob question, but I am very new to Linux networking. I've already spent a few days searching the Internet for an answer to my question, but was unable to find one, ...
1
vote
1answer
1k views

tcpdump not picking up traffic redirected by iptables

The following iptables rule is used to redirect all internet traffic coming in from eth1 to port 3000 at localhost (interface lo with ip 127.0.0.1): iptables -t nat -A PREROUTING -i eth1 -p tcp ...
0
votes
0answers
148 views

Multihoming, NAT and ICMP

My router is the default gateway of a LAN and is multihomed. ISP2 is used for HTTP, HTTPS and ISP1, the default gateway of the default routing table, for the rest of the traffic. Similar questions ...
1
vote
0answers
51 views

Nat Traversal, peers unable to communicate

I'm currently working on a project that requires NAT traversal but I seem to be running into difficulty. I have the following setup running for testing: R1, Verizon Fios router connected to the ...
0
votes
1answer
443 views

Virtual pfSense Appliance on VMWare Host

I am having some issues setting up the WAN side of pfSense. I have ordered a dedicated box through a hosting service with ESXi loaded on it. Along with that I have 3 public IP addresses that will ...
0
votes
2answers
1k 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 ...
0
votes
1answer
187 views

ldirectord NAT load balancing does not work with negotiate checks

I am using ldirectord for loadbalancing two HTTP servers. On the load balancer box i have the following network configuration: eth0 is used for internal purposes and does not take part in load ...
0
votes
1answer
140 views

Server Hosted at Data center Internal IP address on hyper-v guest OS

I have a hosted server that’s located at a data center that I pay for monthly (www.liquidweb.com). The server is running windows server 2012 standard. The server is used to host a SQL database and a ...
0
votes
1answer
184 views

iptables nat taking 30 seconds to start redirecting

I am implementing a SIP Proxy that should be able to redirect all RTP traffic between two clients that can't reach each other. To implement that, I decided to manipulate the negotiated addresses in ...
0
votes
2answers
367 views

IP and Port Forwarding on ASA 5505

I have an ASA 5505 with outside network of public ips 95.123.234.64/26 and inside network of private ips 10.22.33.0/24. I would like to redirect any tcp traffic that hits 95.123.234.67:80 to a public ...
0
votes
1answer
92 views

NAT and find inside global address

To try to find the inside local address of a host, on a LAN with 1 Cisco wireless router, I run nping on one Windows7 host 192.168.1.138. C:\>nping --ec "public" -c 1 echo.nmap.org SENT ...
-2
votes
1answer
171 views

Allow LAN to access External Internet, Iptables

I have an internal network behind my router on eth0, and I have my router connected to the internet thorugh wlan0. I can't access the internet from inside the lan, how can I fix this? wlan0: ...
0
votes
1answer
534 views

NAT / Port Forwarding with iptables firewall [duplicate]

I've got the following setup: firewall (iptables) eth0 internal interface, 192.168.2.10 ppp0 external interface, public_ip (IP masquerading) server1 (192.168.2.11), service 1 (port 443) server2 ...
0
votes
1answer
765 views

IOS Port Forwarding and NAT involving a VPN

We have a Cisco 1921 router running IOS 15.1 at one of our branches which is connected via a L2L IPsec VPN to a ASA5510 running ASA 8.2 at our headquarters. The network looks something like this: ...
2
votes
1answer
545 views

Ping responses to floating IPs do not reach the router (iptables/nat)

I'm running OpenStack, and I'm having trouble accessing my instances from floating IPs, from anywhere except the network controller node. I've got a Folsom deployment with FlatDHCP, not running ...
0
votes
3answers
251 views

IOS Nated port forwarding

I have cisco ios router with ios C1900 Software (C1900-UNIVERSALK9-M), Version 15.2(4)M1. And I have setup Nat with port overload (one public IP). And there is a static mapping: ip nat source static ...
1
vote
1answer
187 views

Checkpoint - Wifi Bridge mode kills round trip requests?

I'm fairly sure this is either a NAT or routing question, but it's one that continually has me stumped. The hardware is a Checkpoint Safe@Office firewall. The default mode of operation is that wired ...
3
votes
1answer
859 views

Dual Cisco Router Stateful Firewall

At my company we have a single Cisco 3925sec/k9 router running BGP with 2 ISPs. Now we want to purchase a redundant router of the same model to eliminate a single point of failure. I can set up BGP ...
1
vote
2answers
364 views

VoIP client permamently losing connection after ISP IP reset

I have a SIP client device connected to my ADSL router, so it is behind a symmetric NAT. My ISP resets the client's IP every 24 hours, it looks like this in the router log: Mar 26 12:36:56 daemon ...
0
votes
2answers
236 views

NAT from Pvt ip to PublicIP

I have a gateway machine with 2 NIC: eth0 with public IP and eth1 with private IP. On eth0 I have 4 public IP aliased, I wanted to NAT public IP to private IP and I used DNAT to do that uisng ...
0
votes
1answer
81 views

Restricted cone NAT

If two hosts X and Y are connected to the Internet with NAT. Both NATs are of cone-restricted type. Now assume there's a server Z which stores all translated public addresses of X and Y. Both X and Y ...
0
votes
1answer
107 views

NAT/PAT port and address selection

I am currently having some issues with TCP port reused too often (under 2 minutes) for a source NAT and I was wandering what is the algorithm used to select the IP and port for a SNAT. Here is some ...
2
votes
4answers
8k views

Differences between bridged and NAT networking

I don't fully understand the differences between NAT and a bridged connection over an virtual machine. As far as I've found, machines which are on the same network with our host machine can access our ...
2
votes
1answer
443 views

Can't connect to instance via floating IPs, not natting/forwarding properly

I'm having trouble getting floating IPs to work properly on my OpenStack setup. It looks like the controller node (running nova-network) isn't forwarding the traffic to the instances. I've got a ...
0
votes
1answer
217 views

Apache configuration to serve pages from other local machines behind NAT firewall

I have one public IP address linked to Apache on Ubuntu through a NAT modem. How do I configure Apache to serve pages from other machines which are also behind the same NAT modem? (I do not want to ...
0
votes
3answers
157 views

Cisco 2900 configuration

I agreed to help a non-profit figure out their network woes. Nothing had been documented and the folks that set the system up aren't available. Wires were cut and left hanging. The organization has ...
1
vote
1answer
2k views

Cisco ASA 5520 Unable to access external IP on Internal Network

I have an internal network of 192.168.0.x and I have a server nat'd to an external IP address we have. I can't figure out how I need to change my configuration for this thing to get it to work. I'm ...
1
vote
1answer
169 views

how to make my Linux to listen on his public ip rather than the private IP

I have a virtual machine on some public cloud. the physical IP is not routeble. the ISP provided for me with a public IP and the NAT is being done using the ISP FW. on that Server I'm running ...
0
votes
1answer
693 views

IPTABLES nat maintaining source IP address with CSF

We have been using CSF on a virtualized (OpenVZ) environment successfully for a while combining venet and bridged interfaces so we can use public IPs + local addressed virtual systems. Kernel IP ...
2
votes
1answer
328 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 ...
0
votes
1answer
557 views

Port forward (NAT) based on domain/URL

I currently have my Time Capsule to forward all inbound requests on port 80 to my Mac Mini which runs a web server with its local ip address of 192.168.1.8. I also have DNS set up so that if I go to ...
2
votes
2answers
358 views

How are connections differentiated from behind NAT routers?

Background: I have a very simple server program written in PHP. It's mostly working, but only as long as there is not more than one client per site. Questions: How does a NAT Router (typical SOHO ...
1
vote
1answer
221 views

Passive FTP that would work inside and outside of NAT

I'm using vsftpd 2.2.2 behind the NAT. To make it work, I set pasv_address to my external (internet) IP. Now the problem is with clients that connect it through the LAN - they try to connect to the ...