Remote-access Guide

linux remote access nat

by Baron O'Kon III Published 2 years ago Updated 2 years ago
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13 Best Tools to Access Remote Linux Desktop

  1. TigerVNC. TigerVNC is a free, open-source, high-performance, platform-neutral VNC implementation. It is a...
  2. RealVNC. RealVNC offers cross-platform, simple, and secure remote access software. It develops VNC screen sharing...
  3. TeamViewer. Teamviewer is a popular, powerful, secure, and cross-platform remote access and...

Full Answer

How do I connect directly to a NATed server?

Connect Directly to a NATed Server via a Reverse SSH Tunnel While the above method allows you to reach homeserver behind NAT, you need to log in twice: first to relayserver, and then to homeserver. This is because the end point of an SSH tunnel on relayserver is binding to loopback address (127.0.0.1).

How do I create a NAT router in Linux?

The Linux kernel usually posesses a packet filter framework called netfilter (Project home: netfilter.org). This framework enables a Linux machine with an appropriate number of network cards (interfaces) to become a router capable of NAT. We will use the command utility 'iptables' to create complex rules for modification and filtering of packets.

How to reach homeserver behind NAT?

While the above method allows you to reach homeserver behind NAT, you need to log in twice: first to relayserver, and then to homeserver. This is because the end point of an SSH tunnel on relayserver is binding to loopback address (127.0.0.1).

Which is the best remote access tool for Linux desktop?

9 Best Tools to Access Remote Linux Desktop 1 TigerVNC. TigerVNC is a free, open source, high-performance, platform-neutral VNC implementation. 2 RealVNC. RealVNC offers cross-platform, simple and secure remote access software. 3 TeamViewer. Teamviewer is a popular, powerful, secure and cross-platform remote access ...

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How do I connect to a Linux server without GUI?

If you don't have a GUI, all you need is a remote console - this is typically achieved with ssh which combines very good security with value added services like scp (remote file copy).

How do I connect to NAT behind?

To connect the Client to the Servers behind NAT, do the following:On Server 1, set the port range 20111-20210 and the public IP address of the router.On Server 2, set the port range 20211-20310 and the public IP address of the router.On Server 3, set the port range 20311-20410 and the public IP address of the router.More items...

How do I make NAT on Linux server?

DetailsConfigure first NIC card, eth0 for Internet with a Public (IP External network or Internet).Configure second NIC crad, eth1 for LAN with a Private IP (Internal private network).Configure Gateway. ... Configure /etc/resolv. ... Delete all the iptables rules present, specially NAT. ... Set up IP FORWARDing and Masquerading.More items...

How do I access a Linux machine remotely?

Connect to Linux Remotely Using SSH in PuTTYSelect Session > Host Name.Input the Linux computer's network name, or enter the IP address you noted earlier.Select SSH, then Open.When prompted to accept the certificate for the connection, do so.Enter the username and password to sign in to your Linux device.

Can you VPN behind NAT?

NAT can break a VPN tunnel because NAT changes the Layer 3 network address of a packet (and checksum values), whereas the tunneling, used by an IPSec or L2TP VPN gateway, encapsulates/encrypts the Layer 3 network address of a packet with another Layer 3 network address, stripping it off on the other side.

How do I connect to NAT IP?

1-to-1 NAT for Mail Server 1: For traffic inbound to the External interface, if the destination IP address is 203.0. 113.25, change it to 10.0. 1.25....Network 1-to-1 NAT ConfigurationOpen a configuration file in Policy Manager.Select Network > NAT.Click the 1-to-1 NAT tab.

What is NAT gateway in Linux?

IP forwarding and a NAT rule are then used to route traffic from the private subnet out to the external network. The traffic from the internal servers will appear to be originating from the gateway IP address. Externally generated traffic will reach the gateway and have no visibility of the private subnet.

How do I find my NAT IP address Linux?

Type the following dig (domain information groper) command on a Linux, OS X, or Unix-like operating systems to see your own public IP address assigned by the ISP: $ dig +short myip.opendns.com @resolver1.opendns.com. You can also type: $ dig TXT +short o-o.myaddr.l.google.com @ns1.google.com.

What is NAT in Ubuntu?

NAT or Network Address Translation allows multiple computers on a private network to share a common IP to access the Internet. One set of IP addresses is used inside the organization and the other set is used by it to present itself to the internet. This helps in conserving limited public IP space.

Is there RDP for Linux?

The “RDP” Method The simplest option to enable remote connections to Linux desktops is by using the remote access tool built directly into the Windows OS: Remote Desktop Protocol (RDP).

Is RDP better than VNC?

There are several major differences between VNC and RDP: An administrator and a user on a device can both see the user's screen at the same time. This makes VNC ideal for handholding sessions such as remote customer support and educational demos. RDP is faster and ideal for virtualization.

Does RDP work on Linux?

You can also use RDP to connect from Linux machines to Linux machines if needed. It is convenient to use RDP for Ubuntu so as to connect to virtual machines running in public clouds such as Azure, Amazon EC2, and Google Cloud. There are three the most used network protocols to manage Ubuntu remotely: SSH (Secure Shell)

What does it mean to be behind a NAT?

If your router is behind NAT (Network Address Translation), then it is not directly accessible from the Internet. As a result, any services running on your router is not directly accessible.

How do I know if my router is behind NAT?

Go to www.whatismyip.com. If the IP it shows is different from the IP of your NIC, you're behind a NAT. If by NAT you mean any NAT including a WIFI router for example click the windows button, type cmd, click on command prompt, type in ipconfig and press enter, see what it says to the right of "IPv4 Address".

What kind of NAT Am I behind?

In order to find out if you router is behind a NAT, you need to trace how you are connected to internet. Go to checkip.dyndns.org You will get your public IP address. If there is more than 1 hop, you are behind a NAT.

How can you tell if you are behind a NAT firewall?

Not sure if your wifi router has a NAT firewall enabled? Try connecting two devices to the same wifi network, such as a laptop and smartphone. Now, on each of them, run a Google search for “what's my IP?” If you see the same IP address for both devices, you're probably behind a NAT firewall.

What does FN do in SSH?

With -fN option, SSH will go right into the background once you successfully authenticate with an SSH server. This option is useful when you do not want to execute any command on a remote SSH server, and just want to forward ports, like in our case.

Can you use a VPS as a relay host?

You could set up a relay host using a VPS instance with a public IP address. What you do then is to set up a persistent SSH tunnel from the server in your home network to the public relay host. With that, you can connect "back" to the home server from the relay host (which is why it's called a reverse tunnel).

Do you type SSH password for relayserver?

One thing to take note is that the SSH login/password you type for localhost should be for homeserver, not for relayserver, since you are logging in to homeserver via the tunnel's local endpoint. So do not type login/password for relayserver. After successful login, you will be on homeserver.

How does NAT work?

NAT just works similar to the subtenant problem mentioned above. Every subtenant family represents an IP address in the local net, every subtenant family member represents a port number, the landlords represents a router and the recipient acts as an arbitrary computer in the internet.

What is network address translation?

Network Address Translation generally involves "re-writing the source and/or destination addresses of IP packets as they pass through a router or firewall" (from http://en.wikipedia.org/wiki/Network_Address_Translation)

What is the prerouting chain?

As the name implies, the PREROUTING chain is responsible for packets that just arrived at the network interface. So far no routing decision has taken place, therefore it is not yet known whether the packet would be interpreted locally or whether it would be forwarded to another machine located at another network interface. After the packet has passed the PREROUTING chain the routing decision is made. In case that the local machine is the recipient, the packet will be directed to the corresponding process and we do not have to worry about NAT anymore. In case that the recipient is located in a (sub-)net located at a different network interface, the packet will be forwarded to that interface, provided that the machine is configured to do so. Just before our forwarded packet leaves the machine it passes the POSTROUTING chain and then leaves through the network interface. For locally generated packets there is a small difference: Instead of passing through the PREROUTING chain it passes the OUTPUT chain and then moves on to the POSTROUTING chain.

Where do subtenants put their letters?

The subtenants have to put their letters into the postbox at the landlord's office

Is Netfilter easy to configure?

The netfilter framework is very powerful but still quite easy to configure once you are used to the syntax. Many tasks can be accomplished and although at first sight the commands are cryptic, they dismantle after some practice to very well structured patterns that allow quick and simple administration.

Can NAT help you?

Although you may not expect it , but NAT can even help you in such a case! Let us assume that only a few ports can be reached from your local network. First of all one has to find these open ports. One wide spread utility to use is nmap: (please scan your own computers only, scanning unknown computers can be interpreted as a first step to intrusion!)

Do you have to choose NAT?

For NAT we always have to choose the nat -table. A command might need further options, for example a pattern and an action to perform in case the pattern matches.

What is Reverse SSH Tunneling?

The concept of reverse SSH tunneling is simple. For this, I needed another host (so-called “relay host”) outside the restrictive cave network. The Raspberry Pi I will use is located at my home. It has an IP address that is publicly visible and unique to me. I can connect to it from anywhere on the internet. I will refer to it as the “Pi.”

Set up a Reverse SSH Tunnel on Linux

Let’s see how we can create and use a reverse SSH tunnel. We assume the following. We will be setting up a reverse SSH tunnel from the cave server to the Pi so that we can SSH to cave server via the Pi from another computer, such as a laptop. Let’s call that computer “laptop.”

Connect Directly to a NATed Server via a Reverse SSH Tunnel

While the above method allows you to reach the cave server behind T-Mobile’s NAT, you need to log in twice: first to the Pi and then to the cave server. This is because the end point of an SSH tunnel on the Pi is binding to loopback address (127.0.0.1).

Set up a Persistent Reverse SSH Tunnel on Linux

Now, after proving that this concept works, I made the tunnel “persistent.” This means that the tunnel is active all of the time and can reestablish itself in the case of temporary network congestion, SSH timeout, the Pi rebooting, etc..

What is remote desktop protocol?

Accessing a remote desktop computer is made possible by the remote desktop protocol ( RDP ), a proprietary protocol developed by Microsoft. It gives a user a graphical interface to connect to another/remote computer over a network connection . FreeRDP is a free implementation of the RDP.

How does RDP work?

RDP works in a client/server model, where the remote computer must have RDP server software installed and running, and a user employs RDP client software to connect to it , to manage the remote desktop computer.

What is XRDP server?

XRDP is a free and open source, simple remote desktop protocol server based on FreeRDP and rdesktop. It uses the remote desktop protocol to present a GUI to the user. It can be used to access Linux desktops in conjunction with x11vnc.

What is a clutter free user interface?

A clutter-free user interface makes working easy for first-timers. You can customize email templates, and rebrand the Linux remote desktop application to use your company’s name, logo, favicon, and portal URL.

How many users can use VNC?

You can get VNC connect for free for home use, which is limited to five remote computers and three users.

What is a VNC?

VNC ( Virtual Network Computing) is a server-client protocol which allows user accounts to remotely connect and control a distant system by using the resources provided by the Graphical User Interface ( GUI ).

Is FreeNX a SSH server?

FreeNX is an open source, fast and versatile remote access system. It is a secure (SSH based) client /server system , and it’s core libraries are provided by NoMachine. Unfortunately, at the time of this writing, the link to the FreeNX website did not work, but we have provided links to the distro-specific web pages:

lucas-a

Who in there right networking mind would have a network with a double NAT? CRAZY!

ddennis002

I could imagine its cheaper for the ISP because only one IP is needed... (And europe is out of ipv4 adresses) Around here arent any better ISP options. I would like to forward one port to the server then connect via OpenVPN/Wireguard/... into the local network.

ddennis002

I guess he is behind Carrier grade NAT, basically NAT at carrier level between many customers

lucas-a

I guess he is behind Carrier grade NAT, basically NAT at carrier level between many customers

lucas-a

What do you mean aet dns manually and the rules? are you using zerotier to access your location behind carier grade nat from a vps/rpi and then portforward in the vps/rpi or areyou using zerotier to access the server directly from the client (phone, laptop,etc)?

lucas-a

and that vpn routed all traffic or only traffic destined for the server?

lucas-a

This also routes all traffic through the vps instead of connecting the devices directly.

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