Many people use public wireless networks in restaurants, cafes and libraries. Wireless networks give them the opportunity to browse the Internet or get work done without confining them to their offices. When using a public network, however, you have to make sure that you protect yourself from other users that know how to monitor your activities to gain personal information about your bank, email and credit card accounts.

Protect Your Computer with a Firewall

Whenever using a public Wi-Fi connection, you should use a firewall that prevents other people from eavesdropping or gaining access to your computer. Firewalls are not completely foolproof, but they do offer considerable protection. Many operating systems now include firewalls. Enable them and you can surf the Internet in privacy.

Encrypt Your Files

If you keep sensitive information (bank account info, credit card numbers and the like) on your computer, then you should consider using an operating system that allows you to encrypt those files. Encryption makes it difficult for other people to read the information in those files. Since you cannot rely on the Wi-Fi administrator to enable encryption, you should use an operating system that allows you to control encryption on your end.

Don’t Type Sensitive Information

Prevention is the best protection. If you avoid typing sensitive information while on a public network, then no one will be able to grab your passwords and account numbers. This might seem like an inconvenience for those working out of the office, but it offers a level of protection that you cannot get from software.

Stay Offline Unless Necessary

Finally, don’t connect to the wireless network unless you are actively using it. This reduces the amount of time that hackers can use to gain access to your system. If you don’t plan to use the Internet for a period longer than ten minutes, then just disconnect from the network.

Even though we use the Internet for everything, few understand routing. A router’s job is to efficiently transport packets from network to network. Generally, the networks in question are far removed across the Internet from one another – and therefore, packets will pass through several routers to get where they’re going. Routing protocols are how routers “know” what to do with any given packet.

Inside the router is a routing table, which is basically a giant list of networks. The router looks up what network the packet is going to, and based on that network, the router selects the best interface to get there. Dynamic routing is automated; routers make “decisions” on the fly, based on resource availability. In contrast, static routing is a manual process where you program your router to always do the same thing. One of the values on a routing table is the metric; a lower metric is preferred for the next hop.

The next hop is a particularly important concept in routing. This is because even though the packet is going all the way across the Internet, each router is only concerned with where it has to send the packet. Another important concept is convergence, which occurs when two or more things come together. When the network changes, it is important that the network converge to compensate. While this convergence is happening, packets are sometimes dropped; therefore, keeping convergence times low is particularly valuable. Sometimes in the process of convergence, a packet gets stuck, going back and forth between two possible routes; this is known as flapping, and can cause the packet to be dropped.

Within routing, an AS or Autonomous System, has a unified, well defined routing policy. Inside a given AS, IGPs or Interior Gateway Protocols, are used. Between autonomous systems, EGPs, or Exterior Gateway Protocols, are used. The default routing protocol for the Internet is BGP, Border Gateway Protocol; this is a specific example of an EGP.