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Questions tagged [nat]

For questions about Network Address Translation (NAT), a method of modifying network address information in IPv4 packet headers.

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organisation with administrative network can't reach our website [on hold]

I have hosted wordpress web site for my client. The site is hosted on cloudways, the DNS is managed through telnet. The site works fine except for one organisation that works with an own ...
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How to do IP masquerading on MacOS (10.14+)? [closed]

I am looking for the equivalent Macos command to the linux: sudo iptables -t nat -A POSTROUTING -o en0 -j MASQUERADE The reason i want to do this is I have a VPN that has the default route, but i ...
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How to route a specific users IP from WAN to a specific host IP on a subnet OPT1 (pfsense)

I host a game server, Players and Devs use the same launcher/client that has hard coded ports (5555) that cannot be changed. (No Configuration Files) How would I route Devs to the Development Server [...
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1answer
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How to send a packet across NAT to local machine

I recently read about network address port translation and I have a doubt. Lets say I have a PC(PC1) at 192.168.1.2 under a router with public address 10.74.65.11 . I have another PC(PC2) at 192.168.1....
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NAT setup for two LANs on same router

We have a moxa edr 810 series router , we have few devices connected to the router as below. We are using IPsec tunnel for VPN. From VPN we are able to connect Device 2 , but not able to connect to ...
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Bi directional natting between two lans

I have two lans , say lan1 and lan2 on my router. My problem is that i tried give a lan1 ip to a lan2 device by using bi directional natting , but what i see is that this lan1 ip always resolve to the ...
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2answers
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IP addresses from public IP block in my LAN

If I have NAT or PAT applied on edge router, Would it matter if I use IP addresses from public block in my LAN? And how?
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NAT Problem Fortigate 501e v6.0

I created a VIP and am having trouble connecting this VIP to an IPv4 Policy. When I put it into the destination I get an error: "Failed to save some changes: Entry not found." I am trying to create a ...
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2answers
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ACL: Deny specific host not working

I'm trying to create an acl for use with a nat but I can't get the deny statements working. All hosts on a private network should be accessible, except from a server which should not be accessible ...
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2answers
37 views

Does NAT always translate the destination address of a packet?

From https://www.cisco.com/c/en/us/support/docs/ip/network-address-translation-nat/13770-1.html This document provides a sample configuration with the ip nat outside source list command, and ...
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How does this NAT translate the same public address to different private addresses, without using ports? [duplicate]

From http://www.firewall.cx/networking-topics/network-address-translation-nat/228-nat-table.html translates the same public destination address 203.31.220.134 to different private destination ...
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Without NAT or NAP, can a host in the Internet send a response back to a host in a private network? [duplicate]

Suppose a router device connect a private network and the Internet, and doesn't have NAT or NAPT features. If some application on a host inside the private network sends some packets to a host in ...
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Is a gateway both a router and a NAT?

From Tanenbaum's Computer Networks: The general name for a machine that makes a connection between two or more networks and provides the necessary translation, both in terms of hardware and ...
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Simultaneous dynamic and static NAT not working

Cisco 4200 series running IOS XE with a single public IP address and dynamic NAT, which works just fine. I am trying to add Static NAT to access a server (map external port XX to internal port YY. ...
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1answer
38 views

Juniper SRX Destination NAT for L2TP server

I have a L2TP server on my LAN which I would like to access from WAN and there is a Juniper SRX standing between these two networks. I've had some success with this post: https://forums.juniper.net/t5/...
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NAT->Multicast Setup->ACL? [duplicate]

I am a network newbie and would be amazing for some help. I trying to input multicast (239.10.1.11) onto a router 0/0 interface and would like to output multicast on (239.0.0.2) on interface 0/1. The ...
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2answers
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Can a host in a public network communicate with a host in a private network, by layer 3 alone?

Suppose a private network and a public network are connected by a router or some other device. After a host in the private network sends a message (e.g. a HTTP request) to a host in the public ...
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1answer
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What are the differences between packet forwarding and network address translation in layer 3?

What are the differences between packet forwarding and network address translation in layer 3? Is packet forwarding done by a router between two networks that use public IP addresses? Is network ...
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2answers
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Unable to access Server over VPN behind 2 Fortigate Firewalls; however ping is working

Client -> VPN -> FG1 -> FG2 -> Server Created a VPN tunnel with remote IP 10.20.30.4/32 and local ip 10.20.30.40/32 on FG1, NAT/VIP is established with VIP as 10.20.30.40 and server IP as 192.168.2.6 ...
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2answers
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Are both VPN and NAT alternative ways to provide access to a private network?

https://en.wikipedia.org/wiki/Virtual_private_network A virtual private network (VPN) extends a private network across a public network, and enables users to send and receive data across shared or ...
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1answer
49 views

How do i find out if a LAN is behind a multi-level NAT? [closed]

Not much i can specify here - its obvious that my CPE is NATing my LAN, but how do i find out if my ISP is using a carrier-grade NAT (obviously, without asking them)? I heard that port forwarding is ...
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1answer
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MAc address or IP address? which one gets used from my pc to router? [duplicate]

Question 1) which one is used nowadays? NAT or PAT? Question 2) as I knew, when my pc requests some website, what happens is , the data(packets) from my pc go to router. then router makes the request ...
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1answer
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How do I find out which NAT is getting hit?

I can see in packet captures that my packet's destination IP is getting translated. How do I find which NAT statement is responsible for the conversion if my device has over 200 NAT rules? I'm using ...
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1answer
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How does packet traversal works over a public network with NAT overloading

Let's say I have a private network connected to the internet with default gateway 192.168.1.1 on Router1. Now a host(Host#1, 192.168.1.10) on this network wants to send a packet over the public ...
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2answers
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How can AWS restrict access by private IP?

The official AWS docs state: If you are connecting through an ISP or from behind your firewall without a static IP address, you need to find out the range of IP addresses used by client ...
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How to connect private networks? [duplicate]

I need to connect two private networks. I have the same IPv4 addresses and need to establish connection between them. • How can I connect them? (NAT?) • What type of routing to use? (I know static ...
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Cisco L2TP Tunnel and NAT

I have problems with NAT clients connected to an AP . This AP has an L2TP tunnel established to a Cisco router (7206VXR). The session is UP and the router can ping the IP of the client. The client ...
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Why NAT type detected by `stun` command depends on used STUN server? [closed]

# stun -v stun.counterpath.net |& grep '^MappedAddress\|Primary' MappedAddress = 93.84.76.218:20458 MappedAddress = 93.84.76.218:20458 Primary: Independent Mapping, Port Dependent Filter, preserves ...
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1answer
78 views

Accessing internal website from subnet

I have the following network: - Edge Lite 3 router with public IP on WAN (eth0) and 2 LANs: 1) eth1 192.168.1.11/24 2) eth2 192.168.2.11/24 eth1 is DHCP, I have several work laptops inside. eth2 ...
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1answer
28 views

A question on NAT [closed]

I know ISP's use NAT to provide a home user with a public IP. If multiple devices connect to the internet using the same router all will have different private IP addresses but similar public IP ...
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1answer
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Daisy chaining IOT devices without switches? [closed]

I have multiple IoT board with two network interface in each device. I want to connect them in a daisy chain without help of switch. The eth1 of first device will be connected to eth0 of second device,...
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328 views

Will the data transfer with the destination on the same LAN network be routed through the internet when the WAN IP is used?

I'm planning to set up a Nextcloud locally. I will be using my own domain with a DNS record to connect to my WAN IP and port forward the needed ports to the local machine running Nextcloud. Now of ...
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2answers
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NAT Translation Table Port Number

I had a practice question about a NAT-enabled router with outside address 24.34.112.235 and inside network 192.168.1/24 and three inside hosts .1, .2 and .3. The three hosts all open two connections ...
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Can I make 2 ISP providers' IP addresses into 1 IP address?

We have 2 ISP providers (X, Y) and we have connected the ISPs to a core switch>Sophos firewall>Switch rack>end user (LAN & WiFi). This ISP works on fail-over mechanism. The issue here is that we ...
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1answer
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PAT not translating at all

I am studying for my CCENT. I threw together a PAT practice lab. Other than DHCP and RIP everything is pretty stock. No VLANs No security Just NAT overload on ACCESS router. I am stumped why it isn'...
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1answer
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Source NAT on Juniper SRX300

I'm having issues setting up the Source NAT on my SRX300 firewall. The firewall is connected to an LC-panel through a fibre optic cable in port 0/6. I have set the public ip on that interface and have ...
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2answers
42 views

How could a response be sent to the requestor without requestor's address?

I'm reading this talking about the differences between two fire-and-forget message (for example, under UDP) and a request-response communication (for example, under TCP). I came across this: The ...
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1answer
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Access internal webserver with domainname points to external IP

We have a webserver on our LAN. Externally, we can use the public domainname (let's say business.com) to access the website. Internally, we need to use the local IP. We also want to use the public ...
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1answer
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How to run SIP phones in the LAN (NAT Overloaded to single IP)?

We have a small office network switch connected to a DSL modem for internet and telephony access. Now we would to extend network to another location in the same building for which I deployed a cisco ...
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1answer
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Can VPN on router connected to the modem bypass a double NAT created by two routers unbridged and connected to each other?

I can't seem to get my head around this scenario. If I am right, a VPN configured on the client-side/workstation would definitely bypass double NAT but on this scenario: Modem <-bridged-> Router ...
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Cisco - Change both source and destination on NAT [closed]

Note: As usual I'm dealing with single device so there are limits on what I can change outside of this router. Device: Cisco 1841 IOS: 12.4(13a) Vlan1 - IP: 192.168.0.3 Vlan1 (Default Gateway): 192....
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1answer
304 views

NAT VLANs with same IP Subnets

I have a VMware environment in which VMs are running a simulation suite. The software used has hardcoded IP addresses, about 10-15 VMs, and we are running multiple instances of this software each in ...
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7answers
15k views

Why are IPv4 addresses running out?

I understand that we are running out (or ran out already?) of IPv4 addresses, but I don't really understand why that is. Right now, every home has its own IPv4 address (dynamically assigned, but still,...
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1answer
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Cisco IOS 12.3 - Mysterious NAT - Where is it defined?

I have the following config (IOS 12.3): A.B.C.13 stands for the outside, public IP, bound on interface Fa0/1.52 37.247.X.206 is a public client I am using to test x.x.x.n stands for a random public ...
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Does the VM under the NAT network can contact the dedicated servers? [closed]

I have bellow snapshot's network configration: in the Dedicated Control Server(172.18.1.249) there is a VMware VM1 with ip 172.18.1.247, and it use the NAT network(gateway is 172.18.1.248). I want ...
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1answer
613 views

Port-forwarding rule on Cisco ASA not working - “Drop-reason: (acl-drop) Flow is denied by configured rule”

New to Cisco, so I hope this question isn't too noobish. I am trying to setup a port-forwarding rule to allow "any" SSL traffic in from "Outside" to the web server on my LAN. The problem is apparently ...
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1answer
132 views

ASDM access broken on Cisco ASA 5505 - NAT rule gone wrong

I was trying to setup NAT and Access Rules and apparently did something very wrong because now I cannot get into ASDM at all. I've tried multiple machines and all of them time out. Also the landing ...
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1answer
50 views

Network ( routing and switching) , security

In my company network i am installing new cisco2811 router but i have problem, my LAN network can not ping and access network. i get point to point internet from ISP. PTP IP is 192.186.86.200/24 and ...
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1answer
67 views

Firewall Rule 'Both Ways'

I'd like to think I have a good understanding of NAT and Firewall rules at a basic level, though please correct me if I'm wrong at any point. I've seen many products list their firewall requirements ...
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138 views

Is an SBC sufficient and can it NAT

We have a gateway which faces out to our VoIP SP. As we get more users we need some security in front of it. Currently our gateway terminates directly to the SP. We would like to put a SBC in front ...