How does NAT and VNC work?

[AlmCar]

I have my own network at home. I need to be able to connect to several different devices on my School Network from my Home PC. The router I own has an NAT function. I have been told that I can use a combination of VNC software and NAT to link to the devices in the school. What is the purpose of NAT in this context and how does it work?

 

[frowertr]

You need a VPN. The school needs to setup this for you.

Nothing you can do on your end with NAT.

 

[AlmCar]

Its basically a question that I need to answer for my younger brothers coursework on networking. I told him that that the best way of researching would be to ask someone on this forum. The question with context is as follows:

Maria and Gregor have their own properties in Chora. They need to be able to connect to several different devices on the JRM network from their home PC’s. The ISP supplied router has a network address translation (NAT) function. Maria and Gregor use a combination of Virtual Network Connection (VNC) software and NAT to link to the device that they want to use.

Explain what NAT does in this context.

 

[frowertr]

Hrm homework...

You can lookup NAT on the Internet. A very generic definition of NAT is its basically the backbone protocol that allows multiple devices to connect to the Internet via a single IP. The router keeps track of the individual internal IPs so it knows where to send the appropriate traffic while everything on the Internet only sees the single external IP.

Help with homework is frowned upon here.

 

[AlmCar]

No worries. Didn't realise it wasn't allowed. Apologies!

 

[ViviTheMage]

The question is missing a lot of variable me thinks. But if we can fill in the gaps ourselves, you would need to port forward whatever port you want to connect up externally on the host. Only the host matters when it comes to incoming connections, ie PC connecting to VNC 'server'. So using port 3333 as an example, you would do this:

So Your edge device with ip 123.123.123.123 has to forward the port 3333 to the NAT'd IP of say 192.168.150.2 so that when you connect with a client PC the router/edge device knows where to send the traffic.

Here's a pic that shows what I meant on the server side:

Should note, you only NAT private IP's in an ipv4 world:
http://www.vlsm-calc.net/ipclasses.php

 

[JackMDS]

It really all depends on the good cooperation of the school's IT guys.

In principle when you control the Network.

http://www.ezlan.net/vnc.html

 

[jacobroloff]

Network address translation (NAT) is a methodology of remapping one IP address space into another by modifying network address information in Internet Protocol (IP) datagram packet headers while they are in transit across a traffic routing device.

 

[mv2devnull]

NAT is also referred to as "masquerade". Subjectively, it is either "convenient" or "trouble", depending on viewpoint.

 

[AD5MB]

I believe the answer is: you need to port forward past the NAT to the ISP. the NAT is an obstacle, port forward is the way past it.

 

[Red Squirrel]

Don't forward VNC, that's insanely insecure. Use VPN or SSH tunnel. You forward the SSH port or VPN port, then use that to access anything else on the network as those are more secure channels to leave forwarded.