Update September 2021

This is basically a bit of a brain dump, much of it you don’t really need to know but you should be able to impress your mates at the pub with your knowledge 🙂 I’ll try to keep the descriptions simple which might fudge the actual technical definitions but if you want to know more, just Google! Knowledge is power 🙂

When I remember I’ll add something here that might need further explanation. Some are those dreaded 3 or 4 letter acronyms (TLA /4LAs) This list is now mainly in alphabetic fashion.

ADSL = Asynchronous Digital Subscriber Line. This is where you use your (land) phone line to connect to the Internet. The phone line was designed to transmit Analogue signals (voice) and needs converting to enable Digital DATA transmissions along with Voice. It does this by sending Voice and DATA at different frequencies and this is why you need to use a filter or splitter as some people call them.  Typically ADSL connections will be slower than a (Virgin) “Cable” connection but BT / Openreach are rolling out a new Fibre Optic network – look up BT 21st Century. Basically they are bringing the “Exchange” to every street and this is known as FTTC (Fibre To The Cabinet), in some cases they are also providing fibre connections to the home / premises (FTTH / FTTP).

ADSL Modem = A device that allows your PC to connect to the Internet via the phone line. Similar to the older “modems” used for “dial-up” connections but these use digital signals instead of analogue and are / were actually a hi-bred router (see MODEMS, below). The earlier ADSL modems (routers) quite often tended to be USB devices and you could only connect one PC to the phone line. Now, ADSL Modems are correctly called ADSL Routers and they are “Always on” and don’t need to “dial up” to get a connection. Modern ADSL Routers tend to be a combined device and include a 4 port switch and WAP (Wireless Access Point). Quite often the ADSL Routers are called ADSL Gateways or just Internet Gateways.

The 4 port switch allows 4 devices to connect using Ethernet. The WAP allows you to connect and share the Internet connection with up to 230 device – not that you want to !

ADSL Router – the correct description for the device, See above.

BIOS (Basic Input Output System). This is the “Firmware” built into a PC to enable it to progress to loading the operating system (OS). The main circuit board of a PC has an EPROM (Erasable Programmable Read-Only Memory) “chip” that is stored on a CMOS (Complementary metal–oxide–semiconductor). The BIOS basically is a very simple hardware check to see what is connected to the PC, e.g. Mouse, Keyboard, HDD etc. The BIOS is a dated (IBM Compatible) system and needs a HDD formatted to use “MBR” (Master Boot Record.) This has largely been replaced by an alternative firmware system, known as UEFI.

Bluetooth. This is a short range wireless technology, not to be confused with WiFi. It’s main use is for connecting things like keyboards, mice(?), printers and mobile phones to PCs. It’s also quite popular for connecting things like head phones and speakers. The range in ideal conditions is about 30 Metres but in practice is a lot less. Unlike, WiFi, it isn’t suitable for “Wireless networking”; mainly due to the relatively low data transfer and when it works, it does tend to work quite well! I still think it’s brilliant that I can get in my car and my phone connects to the car automatically using Bluetooth and allows me to have a hands free facility without even taking the phone out of my pocket but like all “radio” technologies (including mobile phones), you’re in the lap of the gods: sometimes it doesn’t work!

Browser. To surf or browse the WWW (World Wide Web), you need a “Browser”. The most common is probably I.E. (Internet Explorer), this is built-in to all Windows(TM) Operating Systems and is usually the default Browser. However, recent changes have made it possible to prevent this from being installed by default. For years, there have been other browsers that you can install and use instead of I.E. These would include Firefox, Opera, Safari and more recently Google Chrome. All browsers have their own idiosyncrasies so it’s a matter of choice. The article on Wiki might explain it a little better.

CABLE (As in Cable Internet) = This is a fibre optic network that uses Fibre Optic and Coax cables to get you on to the Internet. It also allows TV, Voice (telephone) and Digital data to be used at the same time. In the UK Virgin media are now the only Cable provider. Connection speeds will probably always be faster than ADSL but that might change. Most Cable services had brand new fibre optic cables installed about 20 yrs ago so it’s likely that the Internet connection will be a better quality (not always). BT / Openreach are installing new fibre cables and are offering FTTC and FTTP, the latter could potentially offer similar connection speeds to “Cable”.

CABLE MODEM = This is the device provided by your Cable ISP to allow you to access the Internet. It isn’t really a “modem”, it is a router. This device is the property of your ISP and they don’t allow you to use any other type of Cable Modem – unless they supply it. Cable “Modems / Routers” originally only allowed you to connect 1 (one) device / PC so if you want to connect more, you have to use an additional router or switch. A combined device (Internet Gateway) is now the standard issue. It allows connecting up 2 or 4 PCs to the Cable Modem (using Ethernet). Modern “Cable Routers” now include a 2 or 4 port switch and WAP. It is often called a broadband router The current Broadband routers (from Virgin) also include “ports for your landline” and are indeed an “Internet Gateway”. They have a 4 port switch (for Ethernet connections), a WAP (for WiFi connections) and VOB (Voice Over Broadband) facility (which makes it obvious that your land (phone)  line is using VOB / VOIP. To clarify, if you use Virgin and subscribe to “Broadband + Phone”, you will be using the “Internet Gateway router” supplied by Virgin but this may be slightly different if you subscribe to Virgin services using “ADSL”. Virgin TV still uses the same cables as Broadband but needs an extra “box”, which is known as a “set top Box”. Virgin TV is still a separate service which means you can have Virgin TV without a Broadband or Phone.

Connection speed. This is a figure given in Mbps (Megabits per second (not Megabytes). Generally speaking the actual connection speed does not determine how good a connection you will get but it does give you an idea of the potential. The main thing to bear in mind is the “throughput”, Throughput is the yardstick. You may have a connection speed of say 20 Mbps but your throughput might be as low as 12 Mbps and you may have a connection speed of say 10 Mbps and get a throughput of about 8Mbps. Lots of reasons for this but I won’t bore you with the details. A good site to check your throughput is Speedtest it is probably the most used these days.

(The) CLOUD is basically a Marketing Expression. Cloud services are services that can be accessed by any (most) “Network Devices” and these Services are located  “somewhere on the Internet”. Most often the services are accessed via the WWW (World Wide Web). Cloud Services can be available in multiple locations and in multiple Countries and it is virtually impossible to know (for certain) where the Cloud Service you are using is located (Geographically).

For many years networking techies have drawn schematic views of the the company LAN and at some point the WAN (Internet) was depicted as a picture of a cloud, every one knew that the “cloud” referred to the connection to the ISP and that it would be virtually impossible to make an accurate drawing of the data / network paths once it got to the ISP and then back into a different company site so the “cloud” represented unknown data paths between different company sites. Network techies are only really interested in the WAN IP address, which was / is usually a “Static IP Address, because this is ultimately the “Default Gateway” for all “Internet bound” traffic (data). They have no control of IP addresses outside of the LAN.

It would seem that “the Cloud” is now used by marketing people to describe it as a “New / modern feature”. It isn’t new, the facility has been around for at least 20 years but they way it is used is different. Now that we are all using “Always on” Broadband and connection speeds have gone to dizzying heights, “Cloud services” have become more available to the masses. Google, Microsoft and others have servers* that provide “Remote Storage” (Google Drive, Google Photos, MS Onedrive, iCloud etc) and also have servers* that provide “Web content” (Web Servers) and Email servers.

Servers* these are just computers on steroids. They usually have more powerful CPUs, heaps of RAM and mind boggling amounts of storage space.

Google, Microsoft and others all have servers in many different countries and many different cities and in most cases these servers are duplicated (mirrored and replicated) to ensure minimal disruption in case of failure so in principal the “Cloud facility” can be anywhere on the “Internet”. Cloud services can offer such things as remote access to applications so that you don’t need to install the application on your local PC (similar to the “Main Frame” model). Google Docs is a good example and this means that any documents you create can be easily shared with others to collaborate and all these documents are backed up and can be accessed easily from any PC anywhere in the world. To make use of Cloud services, you need a good broadband connection! The “Broadband” connection can include mobile connections using 4G or latterly 5G. Cloud Services are becoming the “main stay” of the modern world, this may be a very convenient  option for a lot of people but for some, having all your data “in the cloud” is not desirable!

DHCP Server. To use any “Network Device” to communicate with any other “Network Device”, each device needs a unique identity in the form of an “IP Address”. The IP Address can be manually assigned but is most often given out automatically by a device on your LAN. In a typical home-user set up, this job is done by the router; which has something called a DHCP Server and basically it knows what other network devices are already connected to your LAN along with their associated IP (and MAC) Address. It is then able to issue an unused IP Address to allow the new network device to join the network (LAN). When you connect the network device (PC / laptop etc) it sends out an electronic message saying “Who am I” and the device acting as the DHCP Server says “You are (IP Address)” So now the network device has a unique IP Address, it can complete the connection and become a member of your LAN. Some network devices are not able to use the DHCP Service and in this case they need to be allocated a Static IP Address. I know you’re dying to know what DHCP means, so its’ “Dynamic Host Control Protocol”. That didn’t help much did it 🙂 The DHCP server build-in to your home router / Internet gateway often doesn’t need any configuring but with most you can specify a “Range” (scope) of automatically assigned IP Addressees and limit this to say 30 or 40  (or whatever you want up to about 250). So basically a DHCP server just makes things easier when setting up networking devices.

Domain Name. From an Internet and Web point of view, a “Domain Name” is simply the “human” identity of a website e.g pcjudo is the Domain Name, so is dvoit, google, facebook etc. You can register any Domain name you want and as long as you keep paying to have this domain name registered to you, anytime someone enters your domain name into a web browser, they’ll get to your website (if you have one). Some websites need you to precede the Domain Name with HTTP or HTTPS and / or WWW. The bit after the Domain Name e.g.  was originally a quick method to identify the country but that’s all changing. The bit on the end does though need to be included as part of the registered Domain Name e.g the complete domain name for pcjudo would be You can have the same domain name with different bits on the end e.g .com, etc. It is also possible for several different people to have the same Domain Name registered but the end bits would be different, depends sometimes on who registers the name first! How does anyone make sense of all this, see DNS.

DNS (Domain Name System) This ought to be at the top of the list because without DNS, the Internet wouldn’t work and most home and business networks would struggle! DNS and DHCP work together, it’s a “network thing” 🙂 See “IP Address, LAN, WAN and Network.

Basically, DNS is an electronic address book but instead of storing peoples names and telephone number and / or address, it stores “Domain Names” (Website address’s) and the associated IP Address (see DHCP and IP Address) along with other relevant details. In the case of, it’s current IP Address is The IP address could change, depends where I have my website hosted. You might be wondering who keeps the address book (records) up to date! Now this is where the magic starts working and I promise you it isn’t all done by smoke and mirrors 🙂 It’s all done electronically using computers called DNS Servers or Name Servers.

A domain name is registered along with it’s IP Address and is recorded. This DNS record is then shared with all the other DNS servers scattered all over the “Internet”, the sharing bit happens over a period of  about 20 minutes to a couple of days. There are 1000’s of DNS servers around the world (In the Cloud) so after the population of DNS records has completed, you can use any computer (that has an Internet connection) anywhere in the world and see your website. It is magic, any changes to any DNS records on any DNS server are dynamically updated as if it was a living organism.

There are differences between Name servers and DNS servers, in fact there are several different types of DNS server but you can manage quite well with the info you have so far unless you want to enter the realms of black magic LOL. If you really want to know more, Google is your friend!

DMZ = demilitarized zone. A good description can be found on Wiki but basically a DMZ is a special provision that allows such things as Web servers and Mail servers to be accessed from the WAN but access to the LAN is prevented. Never use a DMZ unless you know what you are doing!

Disk Image. A disk image is a complete copy of your hard drive which is saved in a special format and creating them is quick and painless when you use software like Macrium Reflect. When your hard drive fails (and it will) you would normally have to install a new hard drive and then install the OS from scratch. which can be a PITA and might take several days to re-install all the programs that you use and retrieve your backed up data. If you have a recent disk image, you can restore the recent “image” to new hard drive and it will be like having your PC back to normal with hours not days. The caveat being, the disk image needs to be very recent or you will loose any changes that you have made since creating the disk image. Most people keep a few copies of the image as a way of backing up.

“Cloning” is similar but the image is saved / installed directly to a “new” HDD and this then becomes the “Boot” drive.You would normally use cloning when you want to fit a higher capacity HDD and use the current state of your PC. After the cloning process has completed, the original HDD will be disabled and ready for removal.

Ethernet. Until WiFi came along, everyone used Ethernet to network 2 or more computers. These days Ethernet is mainly used to differentiate between WiFi and from using actual cables for connecting devices to a network. The main difference is that with WiFi (Wireless) you don’t use a cable but with Ethernet you do! An Ethernet cable is literally a cable that passes data between 2 network devices. Typically the cable is terminated at each end using RJ45 connections but WiFi does away with the need for a cable and instead uses Radio signals to achieve the same (or similar). Ethernet cables tend to be more reliable than WiFi and in most cases can transfer more date quicker than WiFi.

FIREWALL – see the firewall page and the Special Router glossary.

FTP (File Transfer Protocol). TFTP  (Trivial File Transfer Protocol). Without getting geeky, FTP is a method of transferring (uploading / downloading) files, usually to an external location. Normally you would use an FTP client (application) such as CuteFTP or Filezilla etc to upload or download files from your PC to / from your web site (Just one on many uses) A good example would be where you have a “Web Server” where you store photos and all the family can then upload or download family photos easily. These days it is quite easy to do this using email or Facebook etc but FTP is still my preferred option.

Geek My favourite definition of a geek is – “A geek is someone that is totally focused on computers and technology and likes it that way”

HTTP and HTTPS. Whats the difference! HTTP is unsecured which means that any info you enter on to a web page can be easily compromised, on the other hand HTTPS is designed to be secure so your passwords and banking login details should be safe. If you want more detailed explanation, hop over to Wikipedia but be warned it a bit technical. HTTPS is now the de facto standard.

Homeplug also known as Power line Communication and Ethernet over Mains. This technology is nothing short of black magic 🙂 (joking) You use at least 2 “adapters”, one of which you plug into an Electrical wall socket and then connect an Ethernet cable from the adapter into your Router. This is then the “master”. The other adapter, you connect to a different electrical wall socket (usually in a different room) and then connect an Ethernet cable between the adapter and the network device (Laptop/PC/camera etc). This becomes the “slave” and the magic bit is that data is then passed between master and slave over the mains electrical wiring, is that magic or what! It works brilliantly and is 100% safe. You can unplug the slave and stick it in a different wall socket in a different room and it will still work. Unlike, WiFi it is very reliable and can handle more data faster than WiFi (that might change) and the cost of a couple of adapters is quite low.

Internet. The Internet is basically an infrastructure, which consists of cables, routers and switches. The cables basically use the same cables as the telephone network, which were originally designed for Analogue (voice) signals but all this has been updated over the years to enable Digital signals – which is needed for “data” communications. The Internet allows the use of “Electronic Services” such as WWW (World Wide Web), Email, Cloud storage and more.

Internet Connection. To connect to the Internet, you will need a router* and a subscription to an ISP (see below) or you could use a “mobile device”, which could be a mobile phone, a tablet (with a SIM card), a laptop (with a SIM card) or even a router with a SIM card. When using a “mobile device”, your “Mobile” provider acts as an ISP and uses the Mobile infrastructure so you don’t need a separate “Router”. The fastest connections currently mostly use 4G and give impressive connection results. 5G is still in its infancy but when it becomes mainstream, it will compete very favorably with landline connections but maybe not so much with “cable” connections. 5G will definitely be a game changer but note that mobile connections are “radio signals” and are subject to “atmospheric” and other conditions. This means that if you haven’t got a good “signal”, you won’t get a good Internet connection. The current Mobile operators are O2, Vodaphone, EE (BT) and Three. The signal you get is dependent on the “topology” and the provision of mobile “masts”, some mobile operators have a better coverage that others. If you want to mainly use the mobile operators for an Internet connection, you will need to find out who provides the best signal in your area. Having a “Duel SIM” mobile device can often be a very useful tool.

*Router. apparently it is still possible to access the Internet using a “dial-up” modem instead of using a Router.

ISP = Internet Service Provider. This is who you pay to allow you to access the Internet. In the UK, it will be someone like BT, Talk Talk, Sky or Virgin Media. They all give you access the the Internet (infrastructure), which is basically controlled and maintained by “Openreach” (in the UK). Note BT and Openreach are basically the same animal but Openreach look after the infrastructure and BT is basically the “retail” bit of Openreach.

Internet Gateway  A device that is (usually) a combination of a router, (2 or 4) port switch and firewall. Modern Internet Gateways also have a built-in WAP (Wireless Access Point) and these allow you to connect more than one PC / device to the Internet via your ISP. These devices are also known as Broadband routers and there are many available for ADSL connections. The Routers supplied by Virgin can only be used on the Virgin network but are still an Internet Gateway.

Internet Security Suite. This is a collection of several programs “all in one box” that include Anti-Virus, Anti-Spyware, Personal Firewall and sometimes other bits. The advantage of using a “suite” is that it is very easy to keep it updated and you know that all the different programs / applications will work together (play nicely). Now mainly redundant as Windows 10 does it all.

IP Address. Any device that connects to a network (LAN, MAN or WAN) needs a unique Identity, much the same as you have a house number and postcode. The IP (Internet Protocol) Address IPv4 is currently given in the “Dotted Quad” format and uses 32 bits so the IP address of your PC on a LAN maybe something like any other PC on the LAN would have a different but similar IP address like (see private IP address). One way to check what your IP address is click on START > RUN, type CMD + Enter. Then in the window that pops up type IPCONFIG + click enter. This will return your IP address (begins with 10.x.x.x, 172.x.x.x or 192.x.x.x, if it begins with 169.x.x.x you have a network problem), Subnet Mask (usually and Default Gateway (this will be your routers internal IP Address and will be something like 10.x.x.1 or 10.x.x.254 or 192.168.x.1 or 192.168.x.254)

IPv4 addresses are being replaced by IPv6, and use the hexadecimal notation instead of “dotted quad”. IPv6 uses 128 bits instead of 32 bits. e.g. IPv4 would be 0:0:0:0:0:ffff:c0a8:101:101 in IPv6. See firewalls for a bit more info or if you want to fry your brain try IPv6 Basics otherwise Google IPv6

Local Administrator. You might not know what this is so here’s a quick heads up. All flavours of Windows(TM) since at least Windows 2000 have several built-in user types. A “normal” user is able to log in to Windows(TM) and do most if not all they want to do except install software and other stuff. The normal user accounts are the one’s that you should use generally as it is a way of stopping Malware installing itself on the computer. The “Local Administrator” account (usually referred to as Admin) is specific to the computer you are using e.g. Local machine. When you log in to Windows(TM) as the Local Admin, you can do anything you like – install software, uninstall software  and generally do as much damage as you want. If you connect to Internet and surf the Web while logged on as Admin, any Malware floating around will have free reign to install itself quite often without you knowing about it. The best and safest thing to do is to only log in as Admin when you need to do Admin / Maintenance type tasks and try not to spend much time connected to the Internet to reduce the risk.

LAN = Local Area Network. Where you have 2 or more PCs connected (networked) usually in the same building. If you have more than 2 PCs that you want to network, you would use a network Switch or Network Hub (Switches are better) A LAN enables you to share printers and DATA with other PCs on the LAN. The network could be either Ethernet (usually Cat5 or Cat6 cable) or WiFi or a combination of the two.

MAN = Municipal Area Network. Not a term used very often and you probably won’t ever come across one unless you work in IT but basically it’s where several “buildings or sites” are able to connect to each others LAN but they all share a common router to access the WAN.

MODEM. An electronic device (or Circuit Board) that allowed PCs (Digital) to connect to an analogue phone line using a dial-up connection. A MoDem Modulates and Demodulates (converts Analogue signals to Digital signals and Vice Versa). Todays devices are actually “routers” which are digital so have no need to Modulate and Demodulate and since Broadband (always on) the use of “modems” has become redundant, although there is still a situation where Voice and data are separated by filtering (of frequencies) to allow the same cable to carry voice and data traffic

Nerd. Apparently a nerd is “someone who is totally focused on computers and technology”.

Network Device. Generally speaking, any electronic device that is connected to a network is a Network Device and it needs a unique identity in the form of an IP address. It doesn’t seem all that long ago that “Network Devices” were things like PC’s Laptops, Printers and routers but these days we’ve added things like mobile (smart) phones, washing machines, fridges and cameras, along with other monitoring devices. All these devices need an IP address or they won’t be able to become part of your LAN and won’t then be able to share data. Sometimes these devices have to be given a “Static IP address” but most are able to obtain one automatically, see DHCP.

NIC = Network Interface Card. This is basically a circuit board that fits in your PC and has a socket that accepts an RJ45 plug on the end of an Ethernet cable (a.k.a. network patch lead or Cat5 or Cat6 cable). The NIC allows your PC to communicate with other PCs fitted with a NIC. When you have 2 or more PCs connected using the NIC and Ethernet cable or WNIC  (Wireless Network Interface Card), you have a basic Network. See LAN.

Operating System (OS). Without an OS, your device (PC, Laptop, Tablet and even phone) would be just a box of electronic components. The OS, basically makes your electronic device a “usable device”.  The OS may have certain programs / Applications built-in, so that it would be useful after powering up. Things like being able to browse the Web or get email and be able to make a note and take pictures are good examples. Think of the OS being the bottom layer of an open sandwich, all the additional programs or Applications are then run on top of and interact with the OS. some familiar OS’s are Microsoft Windows, Linux Ubuntu, (Linux) Android, Apple IOS, Apple OS X, etc.

Plain Text Email. These days we are all used to email that looks fancy, has smiley’s and pretty graphics etc. However, it wasn’t always like that. Basically email was designed to communicate with others using just bog standard plain text but over time it has developed so that email now typically uses something called “rich text” or “HTML”. This in effect allow you to send and receive emails that are in effect like a Webpage and you can have fancy writing just the same as in a Word processor and you can have fancy graphics (pictures) just the same as a Webpage. Unfortunately, this type of format allows wrong uns to inject / hide malicious code into emails. Most email clients like Outlook and (Mozilla) Thunderbird allow you to send your mail as plain text and to read it in plain text and this is the safest option as malicious code cannot be hidden.

Private IP address. A private IP address is an IP address that is “non routable*” (this means it is not possible to use outside of a LAN). Private IP addresses are classed as reserved and there are 3 ranges of IP address that will only be used on your LAN (when using a router), these IP addresses are to, to and to Most home users and businesses make use of a router to provide “private IP address” to the LAN and the router acts as a gateway to the Internet. Your ISP will typically automatically assign you a “Public IP Address” for the external IP Address of the router. The router then (using DHCP & NAT)  issues “Private IP Addresses” to devices connected on your LAN. The router allows you to access the Internet from your LAN or just one PC. If you don’t use a “router”, your PC will have a “Public IP address” which is not desirable (see Firewalls and NAT).

*routable means it is capable of of being forwarded to a different network.

Public IP address. A Public IP address is any IP address that is not in the reserved private address ranges. Public IP addresses are routable, which means they can forward data from the LAN (via the ROUTER) to other public IP address which are part of the WAN. “Webservers” would have a “Public IP Address” to make them accessible to any PC connected to the Internet but note the actual IP address of the “Webserver” will probably be a private IP on someone’s LAN. If you want to know more about this, look up “Port forwarding“.  You can check the “Public IP Address” of your ADSL or Cable router by going to

Power over Ethernet (PoE). This is another one of those brilliant bits of technology that seems to be black magic! Basically you use the same Ethernet cable for data and power, so if you have a network device that needs power, you can use the same cable, which means less cabling!

ROUTER. (Pronounced rooter in the UK) This is a network device that has 2 or more NICs (Network Interface Card) The purpose of a router is to enable your PC to access other networks and often to provide security.

Each of the NICs have a different IP address which are (usually) on different networks. It’s probably easiest to imagine 2 doors, door 1 would have an IP address of say and door 2 (different networks) Now imagine a corridor between the 2 doors, traffic (data) coming from either of the doors would just pass through one door to the other but a lot of  / most routers also include a firewall, which use rules to “filter” traffic between the doors (through the corridor).

Typically a home router will have a firewall built-in. It will have a “Public IP address” on the WAN side and a “Private IP address on the LAN side. Each of these doors has a guard or sentry that checks the credentials of anything trying to go through the door, with basic routers all that happens is that it advises Internet bound traffic where to go (which router to go to next) and stops any unauthorized traffic from gaining access to your LAN from the Internet. Even basic routers do more than that but you don’t want to know 🙂

If you are sharing printers on your LAN, each LAN device will have a similar IP address – something like or etc so any device on the LAN with a 192.168.0.x IP address can be accessed by any other 192.168.0.x on the LAN (i.e. Data traffic will pass traffic through the LAN door but not the WAN door). However, when you want to access the Internet, the IP address of a Website will be a “Public IP Address” – say (Google), the router will then act as a gateway and pass the network traffic through the router (i.e. it will pass through the LAN door and the WAN door). When you use a router, it is always the “Default Gateway”. Typically where a LAN has an IP address range of to, the router will usually be or in some cases

Server(s) basically a “Server” (in computer terms) is a Desktop PC on steroids! They normally have powerful CPUs, lots of memory (RAM) and quite often larger capacity HDD but not always! Generally speaking a “server” is a “stand-alone” device that is often rack mounted in a cabinet but not always. Data centers can have hundreds of cabinets, where each cabinet can hold maybe 10 or more rack mounted servers. The main difference between a “server” and a desktop PC is that they are not (normally) used “interactively”. The OS (Operating System) is different to a desktop PC and is basically designed to provide “Network Services” that are not provided by a standard desktop PC.  Some “Servers” can actually look like “tower” desktop PCs and and in small business and households, these would be tucked away in a cupboard or similar.

The “Server” OS (Operating System) is designed to be more robust than a desktop PC and generally “Servers” have a “job”. In the case of a “File & Print server”, these would normally have a range of printers that can be used by any PC on the network (LAN) and generally they would have a large capacity of storage so that users of the LAN can store documents, photos etc (instead of storing them on their local PC). The documents would then be available to any PC on the LAN.

In my (home) set up, I have a “server” running Linux CentOS. The “server” (device) has an average CPU but has lots of RAM and a Raid 5 2TB storage array. It is used basically as a file server for storing documents and photos etc and all these can be accessed by any PC / Laptop on the LAN. To aide this, I have SAMBA installed on the CentOS server. This might be a bit of overkill for most households but I’m a geek 🙂

I also have a few “Websites” and these are stored on “Web Servers” at a “Web Hosting” facility about 30 miles away. The job of the “Web servers” is to serve “Web Pages” on the WWW (World Wide Web). This means that anyone from anywhere in the world can access my web sites.

There are many “Servers” used on the “Internet” and these provide many different services or have specific “jobs”. DNS servers are the main stay of the “Internet” and make the WWW (World Wide Web) possible. We also have “Email Servers” that allow us to  communicate with each other.

“Servers”, in principal, are devices that “serve” in a network environment . They can be found on the LAN or the WAN (Internet) and in all cases they are designed to be accessed remotely. Some “servers” have multiple “jobs”

SPECIAL ROUTERS. I’ve stuck this in because it is possible to use an old PC to act as BOTH firewall and Web proxy, these tend to use a non Microsoft operating system – usually Linux and all they are designed to do is act as a Firewall and Web Proxy. My favourite that I have used for years is Linux SMOOTHWALL and as far as I know I don’t have any problems with other PCs on the Internet accessing my LAN.

Using my example of a box with 2 doors and a tunnel between the doors, some network traffic is stopped at the door and some is let through into the tunnel. The tunnel is where a lot of stuff happens, depends on whether the “routing” is part of a firewall or proxy setup.

Static IP Address: If you don’t have a DHCP Server or your network device is unable to use a DHCP Server to get an IP Address, you will need to give it one. The IP address you give it will need to be unique, in that it isn’t already being used by any other network device on your LAN. Typically, a DHCP Server will have a range (sometimes called a scope) of IP Addresses that it can issue and when you have to set a Static IP Address, you should use an IP Address that is outside of this range but still within the network range. For example, your LAN (network address) maybe and your DHCP server may have a range of IP Addresses that it can issue from to, that allows it to automatically let 118 devices connect and get a unique IP address. You would need to make sure that any “Static IP Addresses” are to and that the one you choose is not already in use. The “D” in DHCP is Dynamic, which means that every time the network device connects to your LAN, it could get a different (but unique) IP Address. When you assign a “Static IP Address”, this never changes – hence Static.

URL (Uniform Resource Locator), sometimes known as URI (Uniform Resource Identifier). Basically, not much to worry about! It’s a geeky way of saying web address e.g.

UEFI (Unified Extensible Firmware Interface). A more modern “firmware” approach to replace the BIOS method. This enables the OS to “talk” directly to the firmware and makes a more efficient and comprehensive system for the “Boot” operation. HDD need to use the “GPT” (GUID Partition Table) to make use of UEFI. Windows 10 works better using UEFI and GPT

VPN =  Virtual Private Network. This might be difficult to get your head round but here goes. Imagine the Internet (WAN) as being a “Cloud” (like the ones floating in the sky), now imagine that you have a tube and you push it through the cloud so that you have the tube sticking out of the cloud at both ends. The VPN is basically a “tunnel” (tube) that allows you to connect securely to another computer at the other end of the tunnel. Normally when you connect to the Internet your Data path to the other computer(s) on the Internet can go through lots of different routers and through miles of copper and fibre cables and at any point the Data traffic can be intercepted, when you use a VPN this doesn’t alter. However, the VPN software that you use creates a “Virtual Tunnel”, think of the pipe above. All Data passing through this Virtual tunnel is encrypted and encapsulated so that if it is intercepted, the Data is gobbledegook to the interceptee so this is a more secure way of transferring Data “through” the Internet cloud.

Most businesses allow their employees to connect to the company network using VPN and in the case of using WiFi anywhere (see Wifi Security) using a VPN is always a good idea; especially if you are transferring sensitive Data. Having said all of that VPN’s can be compromised but not easily.

WAN = Wide Area Network. In principle this is the Internet! If you had your PC switched on at home and connected to the Internet and then you went to your friend’s house some miles away and his PC was connected to the Internet; it is possible for both PCs to share information over the WAN. When you connect to the Internet you are in fact enabling the potential to connect to millions of other PCs around the world and because all the PCs are “on a common network”, this is called a WAN.  When you browse to a website, the website will be accessible from the WAN, it might be on someones LAN or even more commonly on a DMZ (demilitarized zone). You can maybe think of a WAN or the Internet as being similar to the London Underground, where you have the different lines and each station is then another router that you need to pass through to get to someone’s LAN. However, unlike the London Tube; the Internet is connected in such a fashion that if something goes wrong the Data traffic finds another route – automatically. This makes the Internet very resilient and virtually impossible to switch off!

WiFi (Wireless). WiFi is a networking technology that uses “Radio” signals to communicate between network devices, instead of using cables. When everything is working, WiFi is awesome – no cables to worry about and it’s like a bit of magic! The technology gets better as we progress and to be able to go into a public area, Pub, Restaurant and even on a Train and be able to connect to the Internet to get mail or just surf the Web is nothing short of miraculous but (there’s always a but) I (and plenty of others) have reservations about the security of the data being transmitted wirelessly and about the unreliable connections. The security is easy to address by using encryption but the reliability can be a bit of a pain as this is mainly caused by the popularity of the technology! For convenience, WiFi does take some beating but for reliability, you can’t beat Ethernet cables 🙂

WWW = World Wide Web. The “Father of the WWW” is a one brilliant Tim Berners Lee. TimBL recognized years ago that the Internet could be used for sharing information using a special computer language called HTML (Hyper Text Markup Language). From this “Web Pages” were developed and presented to the “user”  via a “Web Server”. All websites use a web server to distribute the content and “Users” need a “web browser” to view the content e.g. a website. Often one hears the phrase “surfing the (Inter)Net” but the correct phrase is “Surfing the Web“. All Web servers are connected to the Internet in a sort of “WEB” like fashion so that any PC connected to the Internet can access the content of these Web Servers. You might notice in your web browser address bar something like “”. This, in theory, tells your PC to use HTTP (Hyper Text Transfer Protocol) and to connect to a web server (WWW) If the website has been correctly setup, you can actually just type and not bother with the “http://www” bit because it is not needed but there are still a lot of websites that are not setup correctly and to access them you will need the “www” bit. You might notice that pcjudo comes up as “” not “” this is because the “www” bit isn’t needed, neither is the “http” bit because Web Browsers already know that you will be using HTTP to communicate to a web server. However, your bank and other secure shopping sites use HTTPS. This is more secure method than HTTP and if the on-line shop or your bank are not using HTTPS, it may not be the site you think it is so be careful about inputting any sensitive data!

Web Browser / Browser. This is a bit of software that you use to browse / access websites. I.E. (Internet Explorer), Firefox, Safari, and Chrome are the better known ones.

WEB PROXY (a.k.a a proxy server) A Web proxy often shares the same features as a Firewall and can often act as a basic firewall but generally speaking a Web Proxy is not a firewall. The main use of a web proxy is to cache (save) details of websites so that they can be accessed more quickly but most often they are used to filter web traffic and usually include something called “content filtering”. Content filtering is where the proxy administrator can filter the content of websites and exclude anything that contains “adult” or “gambling” or any other type of content, this means that if you try to access say a porn site, the web proxy will block it and will usually give you a warning that the site contains “undesirable content”. The proxy server can also often be used to limit access to the Internet on a time basis, e.g. all Internet access blocked between the hours of say 01:00 and 08:00.