List of computer networking devices

Common basic networking devices:

*Router: a specialized network device that determines the next network point to which it can forward a data packet towards the destination of the packet. Unlike a gateway, it cannot interface different protocols. Works on OSI layer 3.

*Bridge: a device that connects multiple network segments along the data link layer. Works on OSI layer 2.

*Switch: a device that allocates traffic from one network segment to certain lines (intended destination(s)) which connect the segment to another network segment. So unlike a hub a switch splits the network traffic and sends it to different destinations rather than to all systems on the network. Works on OSI layer 2.

*Hub: connects multiple Ethernet segments together making them act as a single segment. When using a hub, every attached all the objects, compared to switches, which provide a dedicated connection between individual nodes. Works on OSI layer 1.

*Repeater: device to amplify or regenerate digital signals received while sending them from one part of a network into another. Works on OSI layer 1.

Some hybrid network devices:
*Multilayer Switch: a switch which, in addition to switching on OSI layer 2, provides functionality at higher protocol layers.

*Protocol Converter: a hardware device that converts between two different types of transmissions, such as asynchronous and synchronous transmissions.

*Bridge Router (B router): CombineS router and bridge functionality and are therefore working on OSI layers 2 and 3.

Hardware or software components that typically sit on the connection point of different networks, e.g. between an internal network and an external network:

Proxy: computer network service which allows clients to make indirect network connections to other network services
Firewall: a piece of hardware or software put on the network to prevent some communications forbidden by the network policy
Network Address Translator: network service provide as hardware or software that converts internal to external network addresses and vice versa

Other hardware for establishing networks or dial-up connections:

Multiplexer: device that combines several electrical signals into a single signal.

Network Card: a piece of computer hardware to allow the attached computer to communicate by network.

Modem: device that modulates an analog "carrier" signal (such as sound), to encode digital information, and that also demodulates such a carrier signal to decode the transmitted information, as a computer communicating with another computer over the telephone network.

ISDN terminal adapter (TA): a specialized gateway for ISDN.

Line Driver: a device to increase transmission distance by amplifying the signal. Base-band networks only.

Computer networking tips and tricks

Running a home network is pretty essential in this day and age.

Thankfully, modern hardware and software has reduced the complexities of configuring networks down to a few setup screens, and the relevant hardware often comes free with an internet connection.

If you have multiple computers, the chances are they're already talking to each other, either through wires or wirelessly. However, while your home network might be up and running, optimising it takes some doing. Follow our simple tips to extract the last drop of juice from your network hardware.

1. Change channel number

Wireless routers operate on a fixed channel. Since most routers ship with a pre-selected channel, the wireless signal may interfere with other routers in the vicinity that are operating on the same channel.

Changing the wireless channel from the factory default is a good starting point if your wireless signal strength is poor.

2. Give the router space to breathe

The biggest advantage of a wireless router is that it can penetrate doors and walls – but that doesn't mean you can just stuff it next to a wall or cordless telephone, or use it as a stand for your stack of DVDs. Treat it with respect.

Try to keep it in a central location, away from other wireless devices; make sure it's not in direct sunlight; lift it off the carpet; and ensure its vents and air holes aren't covered.

3. Improve reception

Try as you might, you'll find it's sometimes not possible to put the router in a good spot. One way around the problem is to buy a router with multiple antennas and point them in a variety of directions covering your home.

Alternatively, if you've already got a router, check whether it's possible to upgrade its antennas to something stronger. However, don't get disheartened if your router doesn't have any antennas. A wireless repeater compatible with your router is a perfect solution.

4. Use WEP

Running an unsecured network will earn you brownie points from neighbours and hackers with cars, but that's about it. Wireless routers support a variety of encryption methods, such as WPA and WEP, but these aren't enabled by default.

WPA2 is the most secure method at the moment, but before deciding on an encryption method, make sure your network cards and adapters support it as well. Bear in mind that older machines – and games consoles such as the Nintendo DS – don't support WPA.

5. Restrict access to specific PCs

If you really don't want to use encryption, you can force your router to only connect to specific PCs. Your router identifies each computer by the unique MAC address of its network gear. Feed it a list of MAC addresses to connect to and you save yourself the trouble of entering a password each time you log in.

The disadvantage is that you'll have to add the MAC address of any new computer before it can get on your network – which is probably a more annoying way of getting things done.

6. Disable SSID broadcast

All wireless routers have a Service Set Identifier (SSID) that identifies them to network computers. Routers from the same manufacturer generally ship with the same SSID; 'Netgear' or 'Cisco', for example.

You should first change the SSID to something unique to set your router apart from those of your neighbours. Then, once all your hardware has been set up, it's better to turn off broadcasting the SSID altogether. This ensures your router isn't displayed in the list of available networks, and won't be a target for potential hackers.

7. Keep the firmware updated

Router manufacturers keep working on firmware, even after hardware has been shipped. In addition to tweaks in the user interface, new versions might make better use of the various components in the router, or add extra features.

Just like with an operating system, it's a good idea to upgrade the firmware of the router regularly – check the manufacturer's website for a new version. In the good old days, there was the risk of a botched firmware upgrade bricking your router, but it's a lot safer today.

8. Familiarise yourself with the router manager

All routers ship with a browser based manager. To use many of the tips in this article, you'll have to log in to this interface – try typing 192.168.1.1 into your web browser for the most common location.

It's a good idea to familiarise yourself with the various options and settings you can tweak from within this software. Many routers also have detailed documentation that's updated regularly, so hunt out the latest manual online.

9. Check your connections

There's nothing more irritating than receiving a 'cannot connect to remote machine' error. To ensure a solid connection, use Ethernet cables where possible. It's also a good idea to check the connection between the two PCs with the ping command.

To do this, simply open a command line and type, for instance, ping 192.168.1.2. You'll need to replace the address given here with that of your target machine. Ping works identically on Windows, Mac and Linux.

10. Forward ports


Many servers and applications – for example, file-sharing software, FTP servers and music-streaming servers – need to serve people outside the network. These applications accept connections on specific ports.

With port forwarding – check your router's interface – you can poke holes in your router and ask it to direct incoming traffic on a particular port (or, if you wish, a range of ports) to a specific computer that's on the network.

11. Change DNS providers

DNS is what fetches you a website by translating the human-friendly address, such as www.pcplus.co.uk, into a bunch of machine-friendly numbers. It also displays the '404 page not found' error, corrects misspelt URLs and finds the fastest route to a web server that hosts the site you want to visit, along with lots of other cool things.

Generally, it's up to the ISP to put up a DNS server. However, there are other free services as well, including the likes of OpenDNS and Google Public DNS.

12. Use USB adapters

These days, it's difficult to find a laptop or netbook without a built-in wireless module, but if you've used one, you'll know that they can't always be relied upon. Network cards with antennas are the best option, but they're really only suitable for desktops.

If you really need both mobility and assurance, make sure you get a USB adapter. Most of them ship with a Windows driver, but many work out-of-the-box on Linux as well.

13. Enable Dynamic DNS

The Dynamic DNS feature enables you to connect to your computer remotely. Back in the day, when real-estate on the web was expensive, it was a wonderful option to show off your HTML skills and host your own website.

Now, by associating your dynamic IP address with a domain name, DDNS enables you to connect to the internet-exposed home computer from anywhere in the world. In addition to enabling the feature on your router, you'll also have to register with a dynamic DNS provider, such as DynDNS.org.

14. Save power with Wake-on-LAN

What's the point of keeping a print server on when there's nothing to print? The smart way to save energy is to use the Wake-on- LAN feature of the network card. Thanks to this, you can put the machine to sleep after it's been configured to wake upon detecting network activity.

15. Encrypt your online activity

With the range of snooping tools now available, it isn't safe to do anything online without covering your footprints. There are lots of tools that promise to encrypt your online activity, making it completely unintelligible to anyone who might be listening in.

Some of the best ones to try are the Enigmail plug-in for Thunderbird, Psi for Google Talk and FireGPG, available for Gmail.

16. Get a Firewall distro

You can configure a firewall on a Windows or Linux machine, and there are also a bunch of third-party software firewalls available. However, building a firewall isn't easy. If you're serious about putting one up, download a dedicated firewall distro, such as Ebox.

17. Install the software

Ebox is distributed as a Live CD ISO and there are VirtualBox/VMWare images as well. It's based on Ubuntu Server 8.04. You can also pull in Ebox packages to a standard Ubuntu Server 10.04 installation.

18. Configure settings

Ebox can be adapted flexibly to your network. You can use it to restrict services that can be accessed and slice the network to keep some areas more secure than others. The distro runs a browser-based interface for adding, removing and configuring the components.

19. Filter content

Besides the firewall, intrusion detection (via Snort) and filtering content (via DansGuardian) are two other highlights of the distro. DansGuardian can also plug into the ClamAV antivirus scanner and filter content based on known virus signatures.

20. Exploit other features

In case you're still not satisfied, Ebox can also act as a gateway and provide a host of other services. It bundles various applications that enable you to turn your network into a VPN, host XMPP chat sessions or run a Postfix mail server, a Squid web proxy and more.

21. Turn on UPnP

Universal Plug and Play helps smart devices that support UPnP to discover each other without any user intervention. Once turned on from within your router, UPnP enables a compatible infrared device, a Bluetooth phone or a FireWire camera to see and talk to each other.

22. Write files remotely

The most logical use of a network is to share files. This is the job of the SMB protocol. Thanks to it, you'll be able to write files to a remote network share via Network Neighbourhood. On Linux, the SMB protocol is implemented by Samba.

23. Share printers remotely

In addition to sharing files, SMB can be used to share printers attached to a Windows machine. Once configured via the Windows Control Panel, a printer can be used to accept print orders or even be managed from a remote machine, irrespective of its operating system.

24. Format shareable partitions as FAT

PCs running Windows can easily see each other and share files. For Linux or Mac machines, ensure the partitions are formatted with the FAT filesystem. Create them as Samba shares and they'll show up under Network Neighbourhood.

25. Plug in USB drives

Once, if you wanted to share files on the network, a network-attached-storage, or NAS, device was the best bet. Not any more. New routers enable you to plug in one or more USB devices that are automatically accessible by all the users connected to the router.

Home Networking Tips

Computers have become an essential part of our everyday life. In addition to being glued to the machines at workplace, people enjoy using the computer at home as a mean of communication, information, entertainment and social networking. As more or less all family members like to use the computer at home so one desktop machine is not sufficient anymore and almost everyone has his own desktop, laptop or tablet in action at home. As everyone has to connect to the internet and share other resources (printer, scanner etc.) and data so a home network has become a necessity these days. Some important guideline while setting up a home connection and maintaining it afterwards are given below:

Wired or Wireless: First you have to decide the type of network you are going to have. In a wired environment, you will have to place a network switch at some central location and run cable to each room where a connection is required. It is more expensive, difficult to setup and not very scalable. But it is more reliable and secure. Wireless network is considered more suitable for home users these days. The main reason is that it provides mobility as home user may want to use the laptop anywhere in the home. Also wireless network is easier to setup and is more scalable.

Type of Internet Access: A similar decision is whether to get an internet service through DSL, Cable or WiMAX. DSL is dependent upon your phone company and the bandwidth may be the best in this case but if you have a bad phone line or the phone company’s services are not up to the mark then your internet service will not be smootgh. Similarly cable internet is a good idea if the cable company’s infrastructure ansd servies are reliable. In case of WiMAX, you normally do not have to call the company to check the last mile as they normally are monitoring the transmission all the time. The bandwidth being offered may be a lot less than DSL. So it is always a tradeoff while choosing the best internet option.

Network settings: Assign static IP addresses instead of using DHCP. In case of Wi-Fi system, change the default admin username and password of the router. Also change the default SSID and disable the SSID broadcast feature. Enable WPA2 security which will encrypt all data moving in and out of your network.

Securing the Network: Use a good antivirus program with latest updates. The program should secure your network from malware, phishing and adware as well. Use updated version of common software. Use a software firewall to keep out unwanted traffic. Keep downloading windows and other software patches and updates so there are no security backdoors to hack your network. Configure Internet Explorer to use a popup blocker and anti phishing feature. Prevent kids from downloading malware. Also avoid unwanted downloads. Always backup your data in case anything goes wrong.

Hardware Security: Take good care of hardware as well. Do not allow anything to spill on your computers. Keep all the system safe form small children. Use UPS and surge protectors for your computers and network hardware. Make sure all the equipment has adequate air flow. The power outlets should not be overloaded.