Welcome to the final part in a 3 part series of articles about routers and routing . Previously I wrote about how routers work and the routing table in parts 1 and 2 respectively. I am now going to talk about IP routing and how you can manipulate routes to “direct” traffic. Read More →
Monthly Archives: August 2011
Welcome to part 2 in a 3 part series of articles about routers and routing . If you have arrived here directly through a search engine you may wish to read Part 1 – How Does a Router Work? first. Here we are going to look at the routing table.
All network devices that use the TCP/IP protocol have a routing table, even your Windows PC has one. ALL devices use their routing table to determine where to send packets. Without a routing table your PC wouldn’t even be able to communicate with computers on the same subnet. Here is a screenshot of the routing table of my PC. To see your own routing table open a command prompt by typing CMD in the run or search box. Then at the command prompt type “”route print” and press enter. Read More →
This article assumes you have an understanding of computer networking basics.
Network Address Translation has several advantages but its primary goal is to allow a single Internet IP address to be shared on a network by multiple devices. Your home router has built in NAT capabilities and does all this automatically. It works by your ISP assigning you ONE IP address to your router, NAT then allows multiple computers to access the Internet through this shared IP address. Read More →
In a previous article I explained what PPTP passthrough is and how it works. In this article I will explain why multiple VPN connections fail with certain routers. This issue only affects PPTP connections and it is directly related to PPTP passthrough.
Here is a brief comparison of how NAT handles PPTP VPN connections differently to normal connections. Read the PPTP passthrough link above for more details:
- When computers make normal outbound connections the source IP address is NATed to the public IP. Source ports are used to uniquely identify the multiple connections.
- When PPTP clients make outbound connections the same thing happens but the call ID AND destination IP is used instead of source ports to uniquely identify the VPN connections. Read More →