Your IP Address is 38.107.179.242

What is Dynamic DNS?

If we picture the Internet as a globally extended postal service, it is easy to understand how Internet communications work. Every bit of data that is sent out over the network is like a letter being dropped in the mailbox. Just like your local postal carrier, your computer uses addresses to deliver your information to the appropriate place.  We call these addresses an IP Address and they look something like “216.239.59.99”.

While most people would get very little out of these number sequences, your computer is able to quickly decode them and transfer data to and from the correct locations. For the sake of the humans who use the computers, the Domain Name System (DNS) was set up. DNS translates the web addresses we type into the IP addresses our computers understand, making it possible to use and enjoy the Internet.

The basic function of DNS is to process our typed web address – www.google.com – into the language of the computer, which would recognize the IP Address 216.239.59.99 and take you to the search engine on the main page of Google. Then when Google provides search results, DNS doesn't just give you a list of IP addresses related to your search. Instead, the process is reversed and DNS translates the IP addresses supplied by the search engine into the nifty web addresses that we can understand.

DNS is an integral part of the Internet and there are millions of DNS servers around the globe involved in the processing of this data. At the top, there are a few “root servers” that control the handling of .com, .org and .net domains. These powerful root servers resolve millions of queries every day.

To take a portion of the load off of the root servers and make the Internet faster for their users, most ISP's run their own local DNS servers which cache a copy of IP Addresses for sites visited by their customers. Because of these local DNS servers, it is possible for the millions of people who use Google every day to use the site without creating a huge amount of traffic to the root servers and causing system wide crashes. The local DNS servers make the Internet possible because, when the ISP runs a local DNS server, the stored information on the IP Addresses of popular sites can be reused instead of querying the root server, making the whole service quicker and less reliable.

DNS does have its drawbacks including the fact that it can be very difficult to configure and installation is often more work than the average user is willing to invest for simply connecting a few friends to your home web or gaming server. Because of this, many companies offer a free service known as “Dynamic DNS” which performs the same function as a DNS server by running a small program on your local machine. This program rediscovers your IP Address at scheduled times or whenever you dial a connection. The discovered information is then sent to the Dynamic DNS provider, which uses the data to automatically update their DNS servers so anyone trying to connect to your machine can find you instantly.

The company provides you a “DNS Name” such as “johndoe.dynamic-dns.com” that will never change even when the IP Address associated with the DNS name changes. Your IP address can change as often as necessary and the Dynamic DNS service will continue to resolve the IP address in the background, giving you uninterrupted connectivity to others who know your DNS name.

What is a User Agent String?

A User Agent String, usually referred to as a UA, will help you to determine suitable web settings and screen resolution. UA is a way of finding out the details of sites that you visit and use when you are web browsing. More importantly for the user, this User Agent String ensures that you're directed to the most suitable version of a web page for viewing in your particular browser. The idea behind this is that you view each site in the most suitable format and you have a more enjoyable user experience. An example of this would be if you were browsing on a mobile phone, this would be detected and you would be directed to a version of the page that has been developed to be viewed more easily in a mobile phone. Not every site will have this technology in place, but when you have US detection, it allows the user to access things far more efficiently.

The User Agent String will also alert sites that you go to about the types of browsing related software that you have installed. As an example, if your UA is as follows (Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.0; Trident/4.0; GTB6; Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1) ; SLCC1; .NET CLR 2.0.50727; Media Center PC 5.0; InfoPath.2; .NET CLR 3.5.21022; .NET CLR 1.1.4322; .NET CLR 3.5.30729; OfficeLiveConnector.1.3; OfficeLivePatch.0.0; .NET CLR 3.0.30729), then the UA detection software will now that the visitor has installed Internet Explorer 8, Windows NT 6.0 (Vista), has Media Center PC 5.0 installed, Office Live Connector and so on. Hence, if the site has a section that is tailored to Vista users, they would be directed there based on the string that identifies they should go to a sub section for Vista.

Programmers who understand how the UA works may use User Agent Spoofing. This is a means of preventing the site's UA software from detecting how they arrived and what software they are using. One option that programmers will use is to find existing UAs and program scripts to use these. A programmer would also be able to implement a blank UA, or run one which will contain information such as a web address so that a site promotes a certain browser or script. The inclusion of screen resolution information in a UA provides information about your desktop size, not the browser window.

IPAM - IP Address Management

If you are responsible for monitoring a network, then you can make troubleshooting on the network much faster if you know how to correct a problematic IP address. One effective option is to reduce internal IPs into block segments for easy monitoring. If there is an issue that arises, you'll find it easier to narrow down where it is coming from and find the erratic IP more quickly.

Should I be managing my IPs?

The simple answer is Yes. By managing your IPs routinely, you'll find that you save yourself a lot of time when you need to correct any problems that arise on the network. If you logged on locally to a User’s computer for example, then started mapping batch files that didn’t run and need to get a file from one of the servers you, you could save yourself time by using IP locators. Instead of hunting around for the server name, you could use the IP by typing \\192.168.1.x - allowing you fast access directly to the server where you can retrieve the file.

To help you further understand this, we'll outline a scenario where it is necessary to manage 1 External IP, 5 servers ((Static) 1 handles DHCP (2k3)), 10 printers (Static), 200 wired PCs/users (DHCP). While it is possible to do this in several ways, the following scenario relates to IP Address Management (IPAM) for a small network. To keep this simple, assume that this is a brand new network with no IPs already assigned. As the LAN Administrator, your internet connection is ready to go (meaning one single external IP).

As you have a firm idea of the number of devices to be networked, the first step is to begin laying out a network plan. The most well known IP is the 192.168.1.x IPs, so that is what will be used in this exercise. The first IP is 192.168.1.0 and the last is 192.168.1.255, for a total of 256 IPs. While a computer begins at .0, as humans we'll start with the IP address 192.168.1. The first five addresses you should allocate should be those of the 5 servers. Make sure you assign these statically, as you don't want to risk any of the servers losing their IP address.

Server 1 is a good choice for your DHCP server, so make this server: 192.168.1.1

Follow on with:

Server 2: 192.168.1.2

Server 3: 192.168.1.3

Server 4: 192.168.1.4

Server 5: 192.168.1.5

The size of your network is likely to grow in the future, so leave space for this by leaving.6 to .9 open.

Following this, there are 10 printers that need to be assigned to multiple users. It is worthwhile ensuring that these are also provided with static IPs, so that there is no confusion or risk of a printer losing its address. Since most offices are likely to have one main or central printer, this is best assigned the IP 192.168.1.10. Planning ahead so that you can assign printer numbers that relate to user groups will also help. That way, you could assign the printer that will be used by group 1 with the IP 192.168.10.11. The printer 2 used by Group 2 would be 192.168.10.12 and so on. If were working at a new facility and you have any input into the design of the network at this facility, then make sure that a minimum of 2 cables for printers are installed at each location. More than any other piece of equipment, you'll find that you have to add additional printers to networks. Just as you left some addresses open for additional future servers, it pays to leave plenty of addresses open for plenty of additional printers.  It is worth leaving 10. to .29 open for printers, as you want plenty of addresses available should you need them in the future.

The next step is to manage the assignment of IP addresses for the 200 PCs that all need to be linked in to the network. If you were to start at .30 and continue through to through you'll have 225 IPs. However, as mentioned, it is worth allowing for expansion in the network and for the addition of further peripheral devices. In that case, it is worth beginning the scope for DHCP at .40 and continuing from there. That means you have 215 IPs for PCs (15 more than you initially need) and it opens up an extra 10 IPs at bottom of the scale (.30 through .39). It also leaves a little room for including any managed switches on the network. Many people prefer to locate these at the high end, as it keeps them separate from the other devices. That means you need to allow that .252, .253, .254, etc will be used for these switches.

So there you have a basic idea of how IPAM works. As you move on to larger networks which can encompass much larger geographical areas, then it becomes increasingly complex. Subnetting is the best option for management in that situation, and it is quite a lot to get your head around. To touch on it briefly, here's how it works in simplest terms:

IP address 192.168.1.1 with a subnet of 255.255.255.0 is not on the same network as 192.168.2.1 with a subnet of 255.255.0.0, although they are both located in the one building. By changing the third octet so that the subnet becomes 255.255.0.0, IP address 192.168.1.1 with a subnet of 255.255.0.0 and 192.168.2.1 with a subnet of 255.255.0.0 are then located on the same network. The 255 is roughly a true/false variable, however the management becomes quite complex, especially if you want to keep the networks separate. Googling the term "subnet calculator" will help you to get an idea of the level of complexity.