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Questions tagged [nat]

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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Traffic does not get routed through vpn

Having set up a tinc VPN node properly (the vpn Connection works): I have set the following options net.ipv4.ip_forward = 1 iptables -t nat -A POSTROUTING -o ens2 -j MASQUERADE If I then set the ...
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Origin IP lost when traffic comes from GRE tunnel and goes to docker container

I was having problems with DDoS attacks and had to purchase a DDoS Protection service. The service was installed by the provider, and the filtered traffic comes from a GRE tunnel. Everything is ...
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Public access to VMs in NAT mode VirtualBox

I am trying to make a vm publicly accessible and it seems I am missing something obvious. Since I do not have any control on the router, I choose NAT with port forwarding. Here are my rules: NIC 1: ...
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Unable to NAT TFTP traffic because iptables is not forwarding the return connection to the client despite TFTP helper creating an expectation

The Problem I have a TFTP server (Machine 'S') and a TFTP client (Machine 'C') on different subnets. They are connected via a router( Machine 'R'). All 3 machines are Debian 9/Stretch. The router is ...
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Router's Parental Controls Really Block All Internet Traffics?

I am using Asus 4G-AC53U router. When I turn ON "Parental Controls" to block a client's Internet access, does the router really block ALL kinds of Internet traffics including system's service (such as ...
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38 views

Allow GRE (IP protocol 47) over Linux router NAT for a subnet

I have network setup as shown below: The VPN server running is windows 2012 server default VPN, which uses GRE protocol. I am able to have VPN connection to that remote vpn server, from my intranet ...
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28 views

NAT timeout how to switch access

The SS server of 127.0.0.1:1080 is also enabled on the NAT server. iptables -t nat -A POSTROUTING -s 10.0.0.0/24 -j MASQUERADE I want him to automatically add REDIRECT --to-port 1080 when it times ...
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26 views

different firewalld rich rule behavior in kvm host compared to kvm guests

I have a CentOS 7 KVM host with a single public IPv4, which is housing multiple guest OS's and acting as a firewall / gateway for guest network 192.168.1.0/24 / nat. I want to run a webserver of 1 ...
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1answer
98 views

Connection refused when accessing container from local network through reverse proxy

I am running Proxmox VE on a root server. There are several virtual containers, on of them acts as a reverse proxy who does TLS termination. On the proxmox machine iptables handles port forwarding ...
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Forwarding Fragments with IPTables / FirewallD

I have a linux (openSuse Leap 15.0) computer that's connected to a cable modem using PPoE (hopefully not relevant to this. EDIT the ppp0 interface has an mtu of 1492 but the eth0 interface it is "...
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NAT: Figuring out IP of broken down machine

I have a machine that was behind a natted router. Unfortunately its harddrive broke down, so I had to replace it. I have port 22 forwarded to it (in the router provided by the ISP) for remote ...
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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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86 views

Creating a NAT gateway with Terraform fails with an error

I'm running a private GKE cluster and want to add a NAT Gateway so I can create firewall rules from requests coming from the cluster (by default, the public IP's for all nodes are ephemeral, thus hard ...
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1answer
51 views

CentOS iptables NAT, client cannot connect to WAN from LAN

I have the following configuration: 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 ...
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66 views

View traffic flowing through NAT machine

I have been put in charge of an HPC cluster recently and the last admin didn't do a great job of documenting everything. We got a notification from our IT Security team that our head node has been ...
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1answer
18 views

Can't configure Dante

Config version: 1.4.x I get "Connection refused" after default 30 seconds in curl and "Connection Failed" immediately in FoxyProxy. Dante config: logoutput: syslog stdout /var/log/lotsoflogs ...
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56 views

Ipsec nat-traversal on port 4500

What is the point of switching the traffic on port 4500 in Phase 1 of IPSec negotiatons From 5th packets onwards? Since the NAT Is already detected in packet 3 and 4 itself, can’t we simply continue ...
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Can I access my VMware workstation intranet VMs through a public IP address

I have a Windows Server with a public IP address (102.1.1.1) and I've installed VMware workstation on it, creating several VMs on it. The VMs use intranet IP addresses, such as 10.0.0.1, 10.0.0.2. ...
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MASQERADE iptables rule not being hit inside docker conatiner

I am trying to route traffic via an OpenVPN tunnel which is running inside a docker container, but cannot get NAT to work +---------------------+ +-------------------+...
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1answer
98 views

CISCO ASA tunnel is up but no traffic

I have reviewed the very similar questions to mine, but my scenario seems different. ASA Version 9.7(1)4 I had a VPN site-to-site ikev1 connection from a remote network in AWS to a remote network ...
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dnscrypt-proxy, iptables, and redirecting (NAT) subnet DNS queries

I have a server with IP 192.168.10.100. It is running dnscrypt-proxy which listens to 127.0.0.1:53 and 192.168.10.100:53. The server also serves as a wifi access point on a standalone network (NAT): ...
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1answer
71 views

Forwarding traffic between two interface

I have a Linux box with two interfaces: ~#ip -4 addr show scope global 2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UNKNOWN qlen 1000 inet 192.168.45.101/24 brd ...
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1answer
35 views

NAT on SonicWall for Debian server

I'm writing because i have a very strange issue with a newly installed debian 9.5 server. This server is behind a NAT made with a SonicWall firewall that assigns a public dedicated address to this ...
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1answer
32 views

Port forwad public ip port to internal server on different interface

Hello I am trying to port forward a public ip:port I have on a wan interface to a server on my lan my server has two interfaces ens19 [WAN] ens18 [LAN] I then have another server connected on the ...
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1answer
73 views

NAT gateway for ec2 instances

I have a public subnet with ec2 instnaces. The route table has 0.0.0.0/0 IGW (Internet Gateway) as default. I tested adding a public IP address to my instance (104.27.142.41/32 as reported by curl ...
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42 views

Redirect web traffic in OpenVPN server

Long story short: I have a functioning OpenVPN server (odroid-XU4 running Ubuntu Mate) and can successfully connect to it from 3 different clients (gentoo, Kubuntu and android). I want to route all ...
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1answer
73 views

NAT setup on AWS

This might sound ridiculous for some, but am trying to setup NAT on lightsail so that I can access my private ec2 instances which are connected using VPC peering. Suppose if 172.31.x.x is my ...
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How to configure internet gateway for NAT'd VM on KVM?

I'm running the Redhat 7 hypervisor, running KVM. The RHEL hypervisor has internet access. The VM is configured with NAT, not as Bridged, and does not have internet access. How would I configure the ...
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2answers
315 views

What is the AWS NAT Gateway?

I'm not sure what caused it, maybe Elastic Beanstalk, but at some point AWS created me a "NAT Gateway" which costs more than my EC2 server instances themselves. What does it do, why does it cost so ...
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1answer
57 views

How to split outbound traffic by destination IPs on aws with static IP?

Conditions are below. Use static IP for all outbound traffic. Send traffic through VPN Connection if it has the specific destination IPs. Send traffic through the Internet if it has NOT the specific ...
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cisco 881 double nat (gre tunnel)

I have cisco 881 and I would like to have double NAT. Also I need to have GRE tunnel. I set up next lab (look at picture topology). I can set up NAT from 192.168.0.0/24 to 192.168.13.0/24 interface ...
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72 views

Port-forwarding traffic to remote server using iptables

I'm struggling to set up an infrastructure where MySQL replication traffic from an Amazon RDS instance is forwarded over an OpenVPN link to a second server. There is an Ubuntu EC2 instance running ...
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For many different TCP hosts, how can I differentiate and route them from the same external IP?

I realize I may be asking the impossible here -- At the moment I use too many elastic IPs, and they cost money. Not only do they cost money...but in a disaster scenario, it takes time to reattach 25 -...
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ESXi 5.5 VM accessible from outside but no outgoing connections

I have an ESXi 5.5 dedicated host with several VMs. Each of them has internal address 192.168.0.x and is reachable via TCP on public address (public class, so I can access them on the internet via ...
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SNAT in RHEL using haproxy/keepalived

I have got a requirement to NAT the outgoing Source Address to a Public 87.x.x.x. we have two interfaces eth0,eth1 etho - internal, eth1-external communication. I tried the below SNAT using iptables ...
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163 views

Add-NetNatStaticMapping not port forwarding to local VM

I'm running windows 10 build 1809 and have hyper-v installed. I have a Linux machine running behind a NAT with internet connectivity working on IP 10.0.5.5. I basically followed instructions on the ...
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1answer
73 views

Test connectivity to NAT Gateway over firewall.

I created a VPC in aws and added a NAT Gateway so my instances in the VPC can consume other resources on the internet. Some of these resources belong to a 3rd party and are behind a firewall for ...
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0answers
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Routing/NAT with Network Protocol Transformation

I'm looking for a way to accept multiple TCP based protocols on any port, then transform and redirect them all to HTTPS and send them over the internet to a server. (The "Server 1" is mine with ...
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1answer
80 views

AWS private subject cannot hit S3 using VPC endpoint

I have a private subnet in my VPC. I've sshed into this instance from a public subnet. Using a nat gateway, I'm able to run aws s3 ls and see all my buckets with no issues. Once I delete the nat ...
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what is a reverse nat and why would i need it?

Though I could find some definitions of reverse NAT (like from here), I couldn't really understand why it is needed. I'd really appreciate some examples.
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1answer
115 views

Mikrotik reverse NAT

Hi, I have attached my current network diagram. I have having problems on how to NAT my public IPs so that each client will use 2 different public IP. My ISP routes 3 public IP to my router over PPPOE....
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1answer
281 views

Using iptables TPROXY instead of REDIRECT

I'm running Debian 8. I'm trying to intercept all packets, and are currently using iptables for this: iptables -t nat -A PREROUTING -p tcp -j REDIRECT --to-port 5000 This seems to work, but it ...
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2answers
74 views

Is it possible to add FQDN to Server behind NAT or to a NAT itself?

I have multiple identical servers behind a NAT. I use the same IP and just change up the port to move between the server via port forwarding.The issue is that i am using self-signed certificates and ...
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1answer
101 views

Linux GRE Tunnel: Remote Address parameter

The Linux GRE tunnel as two parameters, local address and remote address. Suppose I have two routers, the left one is outside of a NAT and right one is inside NAT, then I want to create a GRE tunnel ...
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1answer
91 views

iptables Source NAT with Multiple NIC & Public IP Addresses Not Working

I just have a problem on the multiple NIC & IP addresses server. I've configured my Cent OS 7 server with an additional public IP address which belongs to eth1. When iptables source NAT enabled, ...
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1answer
29 views

ubuntu route traffic to specific remote port via another host

There are three servers: A, B and C. C exposes a service on port 8080 and a firewall rule allows connections from B only. I need to set up A and B so that A can access C too, through B. Please note:...
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iptables stopped translating DNS packets?

# iptables -t nat -S ... -A PREROUTING -d 217.xxxx/32 -p tcp -m tcp --dport 53 -j DNAT --to-destination 10.x.x.9 -A PREROUTING -d 217.xxxx/32 -p udp -m udp --dport 53 -j DNAT --to-destination 10.x.x.9 ...
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491 views

NAT with Hyper-V Internal switch: VM can't communicate with other machines

I have a machine running Windows Server 2016. The machine is hosting a Hyper-V VM, also running Windows. I would like to give the VM access to the network (i.e., connect to other machines on the ...
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1answer
76 views

Can not NAT from IP routed via VPN

I have a linux server running Centos7 that uses a VPN to route to a public IP homed in a remote network. I want to NAT from an IP address on that remote network to a local subnet over a VPN connection ...
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155 views

Docker container hits iptables to proxy

I have two VPSs, first machine (proxy from now) is for proxy and second machine (dock from now) is docker host. I want to redirect all traffic generated inside a docker container itself over proxy, to ...