Networks

[Sayonara]

Oh I see.

 

The standard solution is to use a [acr=Virtual Private Network]VPN[/acr], but I think there are other ways to do it. Google.

[5614]

well ok, i can use a virtual private network, but the reason i was asking was because of another thread 'proxy server' or something, where we're talking about the dos command net send, i was wondering were i wanting to do this to myself, that is, send a message i need an IP address, so if i were at a friends house, and wanted to send a message to myself what IP address should i use?

[Dave]

Let me clarify what Sayo said a bit. Your router will connect you to the internet, and your ISP will assign you an IP to use for your connected session. This IP is available to everyone on the internet; they can connect to it and reach you from anywhere, so we can effectively call it an external address.

 

However, on your actual internal network itself, you can have many computers. So on each of these computers, you can assign an internal ip address; that is, ips that you can connect to from your local network only. In my case, I use 192.168.0.1 as my router address, 192.168.0.2 as my computer, 192.168.0.4 as my server and a few others. So effectively the router "routes" internet traffic from your computers to the internet, but shields people from connecting externally to one of your computers. This type of networking is called a VPN.

 

Have a google for port forwarding, this might help you a bit.

[LuTze]

The standard solution is to use a [acr=Virtual Private Network']VPN[/acr]

No it isn't, a VPN is something different.

 

This type of networking is called a VPN

No it isn't, it's called "Port Address Translation", not to be confused with network address translation (NAT). PAT works by assigning each outgoing connection one of the free ports on the gateway device, when traffic comes back it's addressed to the same port, so the gateway knows which machine on the internal network to send the reply to. Thats why an external machine can't send an unsolicited packet to a machine on the internal network - the gateway doesn't know where to send it because there is no already open port. This is the way all 'interet connection sharing' devices work.

 

NAT on the other hand is a one<->one relationship. An external address is mapped onto an internal one, ports and all so that the internal machine can accept incoming connections from the internet.

 

VPN's are something else entirely. Say you have 2 networks, with the internet in between. All traffic has to go over the internet in clear text if the two networks want to talk to each other. For businesses that are paranoid about security, as well as those wanting to provide homeworkers with access to the internal network from thier ISP, this isn't too handy.

 

What a VPN does is establish an encrypted tunnel between these networks, and all traffic between the two of them goes over that. This provides extra security.

 

What 5614 seems to want is port forwarding, as mentioned by Dave. This, for example, would allow you to serve a website to the outside world by forwarding requests to port 80 on the gateway to port 80 on an internal machine. Any decent off the shelf home router should be able to do this, and it'll work with any protocol that uses fixed port numbers over TCP.