There are two main things to remember when trying to calculate subnets. The first is that that default subnet for a range is 255.255.255.0. This subnet, that we all recognize gives you one network with 255 different addresses from 1 to 255. Fairly easy stuff so far. The second thing to remember is the formula needed to calculate a new subnet. For this we have to go back to basics and remember that the number 255 is made up in binary of 8 bits. To get the number 255, all those 8 bits would be set to 1, each one representing a number in decimal in the following sequence. (1, 2, 4, 8, 16, 32, 64, 128). If you add all these numbers together you get 255.

In order to create our subnet mask we need to “borrow” a certain number of bits from our host address. The host address is the last number in the group of four that makes up our subnet. So in the subnet 255.255.255.0, the 0 is the host address.

We can use the formula (2^n – 2) to figure out how many networks we can make by borrowing certain number of bits. Lets say for example we wanted to make six networks; we would need to borrow 3 bits, because (2^3 – 2 = 6). So we take the three bits from the left of our binary sequence and add them together. (128 + 64 + 32 = 224). So the subnet we need to use for our 6-network system is 255.255.255.224.

Now we’ve calculated our subnet, the next thing we need to do is work out the ranges of our new networks. This is a fairly easy thing to do if you remember one rule. The lowest number in the bits we borrowed from our host address is our guide. In this case, the bits we borrowed were 128, 64 and 32. The lowest of these is 32, so this is our guide number we’re going to use to set up our network ranges.

What you want to do is start off with your guide number, and that gives you the first address of our first network. For example – 192.168.0.32. To get the starting address of the second network, you just add on 32. So the second network will begin at 192.168.0.64. Keep adding the number 32 to find the other network starting points, and you’ll end up with this network address range map:

• Network 1: 192.168.0.32 – 192.168.0.63
• Network 2: 192.168.0.64 – 192.168.0.95
• Network 3: 192.168.0.96 – 192.168.0.127
• Network 4: 192.168.0.128 – 192.168.0.159
• Network 5: 192.168.0.160 – 192.168.0.191
• Network 6: 192.168.0.192 – 192.168.0.223

Note that you cannot use the first 32 or last 32 addresses of the entire 255 address range, (unless you’re using specific equipment that allows it). And there you have it, we’ve calculated our subnet mask, and we’ve worked out the ranges our networks will use. Remember the formula (2^n – 2) and your binary numbers, and you’ll be able to work out any configuration of subnets and networks.

It first needs to be mentioned that your computer may have multiple IP addresses. That’s the case for instance if you are currently connected to the Internet (which you may be since you are reading this text here) or if you have multiple network cards installed.

Each network card on your computer has a local IP address assigned to it. Plus, you get an IP address assigned to your computer whenever you connect to the Internet. The local IP address is only visible in the local network, for instance if a second computer in the network wants to communicate with yours. The Internet IP address on the other hand is often temporarily assigned, especially if you are on dial-up, DSL or cable.

Both local and Internet IP addresses look similar, each with four numbers separated by three dots. The core difference is that local IP addresses can only be accessed locally.

The easiest way to find out about your computer’s IP addresses is to use the ipconfig tool. Start the Windows command line with the hotkey Windows-r, typing cmd and the enter key.

Type ipconfig, or ipconfig /all for a detailed listing.

• IPv4 Address: This is the local IP address of the network card
• Default Gateway: This is the local IP of a router or other device that is used for connections (for instance to the Internet).

You cannot display the IP address that your computer has received from the ISP this way though. To find out my computer’s IP address I open http://www.ghacks.net/ip/ in a web browser of choice.

Your IP address will be shown to you along with the port and browser information. And that’s how you look up your computer’s IP address.

Sometimes it may be important to get detailed information about an IP address. Say you receive spam emails from a particular address all the time, or want to find out more about a person who stalks you, or are a webmaster who wants to find out who tries to brute force their server.

The IP address can provide you with valuable information in all cases. Please note that computer experts tend to use proxy servers or virtual private networks to cover their tracks. You would only see the last IP of the chain in this case, and not the IP of the device where it all started.

IPNetInfo is a lightweight portable software for Windows to look-up IP address information. It basically offers direct access to whois databases that you find on the Internet, for instance at a web host’s website.

The program displays a white text form on first startup that you can use to add IP addresses. It is possible to add IP addresses or hostnames manually, or paste them in from the Clipboard. Options are displayed at the bottom of the screen, of which some are already pre-selected.

The program will automatically resolve IP addresses and convert host names to IP addresses for instance. You can furthermore add a pause between look-ups which may be appropriate if you have added dozens, hundreds or even more IP addresses.

IPNetInfo will perform the selected operations. Each IP address is listed in a row in the main program interface. Core information, like the IP address and host name, country of origin, phone number or abuse email are displayed directly in each row. Detailed information about the selected row are displayed in the lower half of the program.

The information here resemble the whois look-ups on certain Internet sites, where information about a domain name or IP address can be obtained for free.

Reporting and exporting options are available. It is possible to create an HTML report of the look-ups, or save the information to text or xml files.

Another interesting option is located under Help > Show my current IP, which loads a web page where the current IP address of the computer is displayed. This is similar to our own IP address script where you get similar information.

You can download IPNetInfo from the developer website at Nirsoft. The program is fully compatible with 32-bit and 64-bit editions of the Windows operating system.

It is not hard to secure your Wi-Fi connection. It takes changing a setting in the router and entering a password. Many, though, are not even aware that their connection is open, never mind that there are ways to secure it.

Cyber-attack and identity theft are only the most obvious dangers of having an open Wi-Fi connection. But there is another serious danger. If your connection is open and available to be stolen, the chances are good that someone is stealing it. The least malignant implication of this is that your neighbors will be watching Netflix on your connection, slowing you down and bringing a bandwidth cap that much closer.

But the real danger to you comes when your neighbors aren’t just watching Netflix. What if they’re doing something less reputable? What if they’re pirating music or engaging in illegal activities?

The RIAA and other organizations have been pushing courts to try people based on their IP addresses. There have been over 100000 law suits in the United States alone in the last year whose purpose was to obtain personal information on subscribers from ISPs in order to force the person to come to a settlement that ranges from hundreds to thousands of dollars. If your IP address has been tracked downloading music, etc, then you are obviously guilty, right? Well, not exactly. If your Wi-Fi connection is open, then anyone accessing the internet through it will have your IP address. Your neighbor could be the one who was tracked, or even someone driving down the street sniffing for open connections.

For this reason, people have been trying to get the justice system to understand for some time that an IP is not a valid way to determine whether or not a person has been engaging in piracy.

Finally, one judge seems to understand. Judge Herold Baker refused to allow a Canadian adult film site to subpoena ISPs for the personal information of subscribers. He said that an IP address does not equal a person. The fact that this case involves porn means that the judge felt he needed to handle it delicately. A wrongful conviction in a case like this could be even more damaging to a person than it otherwise would be.

Baker then went on to cite a recent mistaken child porn raid, where an IP address was turned into a name–but the named person hadn’t committed the crime. “The list of IP addresses attached to VPR’s complaint suggests, in at least some instances, a similar disconnect between IP subscriber and copyright infringer… The infringer might be the subscriber, someone in the subscriber’s household, a visitor with her laptop, a neighbor, or someone parked on the street at any given moment.”

This case is not a precedent setting case for the United States as a whole, per se. Still, it will be interesting to see if others follow Judge Baker’s reasoning. It’s refreshing to see that a judge seems to understand something about technology. It’s nice to see that the court isn’t totally ruled by the big corporations. I’m not in support of piracy, don’t get me wrong. But I am in support of decisions based on logic and proper information. Hopefully, the trend will spread…

What do you think of the judge’s decision? Do you support it? Do you think other judges will follow suit?

The tool basically allows the user to configure multiple IP profiles that can be activated with the click of the mouse. IP Switcher is a portable software program that displays a two-tiered interface on startup.

The software program displays all connected network adapters at the top and the configured IP configurations at the bottom.

Network adapters are displayed with their name, description, status and current IPv4 and IPv6 IP address.

A new IP address, which actually consists of more than just the IP can be easily added for the selected adapter. It is possible to add a IPv4, IPv6 or IE Proxy IP address easily.

The configuration includes the IP address, subnet mask, default gateway, interface metric and DNS server for that configuration.

The different IP addresses can then be accessed from the Windows system tray. Hovering the mouse over the icon displays the current IP information.

A right-click on the icon can then be used to set an IP address for the selected network adapter. IP Switcher is a handy tool for users who have to work in different network environments that force them to change IP related settings regularly. The 65K program can be downloaded from the developer’s website. It is compatible with both 32-bit and 64-bit editions of the Microsoft Windows operating system and requires the Microsoft .net Framework 2.0.

Every server has an IP address and using specialist websites, a list of domains which point to that IP address can be returned. Several websites do this, and many charge for the service.

If one types in a domain or IP address on myIPneighbors, the site lists other domains that point to that IP. It can be a little unreliable, though, no doubt due to the site’s heavy load.

I have already mentioned that this site does have practical uses. It’s interesting to see how packed your host’s server is, so you can see how good a deal you are getting, and what they are hosting. This could be useful as it’s something hosts rarely reveal but is very important to company’s reputations.

It could also make an interesting tool for doing investigations. Using it, you can see what projects companies are launching if they’re silly enough to put the domain on the same server.

Update: Site seems to be down for some time know, an alternative is DomainByIP

Inexperienced computer users on the other hand might want to take a look at the Simple Static IP networking tool which allows them to set a static IP address with a few clicks of the mouse button.

A user who wants to set a static IP address needs to select the network adapter from the pull down menu on top of the application’s interface. Simple Static IP will then display the current settings of the network adapter including the assigned IP address, subnet, gateway and DNS server.

A click on Enable Static IP will configure a static IP address for the selected network adapter. It is possible to keep the DNS settings or use the router or the Open DNS servers as the dns server for the network adapter. It is also possible to randomize the static IP address by clicking on the Randomize New IP button in the interface.

Simple Static IP is compatible with the following Microsoft operating systems: Windows 2000, XP, 2003, Vista, 2008.

The program will display its basic interface upon execution that is showing four blank rows. The first two rows display the local area network (LAN) IP and computer name while the two other rows display the IP assigned by the Internet Service Provider and the hostname.

The user has to click on the Find my IP addresses button to start the lookup. IP2 will query one of several IP lookup services on the Internet to display the information in the second row. Each entry can be easily copied to the clipboard by clicking on the Copy button next to each row.

The developer lists the services that are used to lookup the external IP address on the website. IP2 can be downloaded from that website as well. The program has a tiny size of only 8 Kilobytes.

They did provide a switch in the user control panel to disable that feature again but this is again a company that is forcing the user to take action for something that they changed.

Open DNS has been covered before on this website and I just want to remind everyone that Open DNS can be used to get rid of search boxes from your provider. Setup of Open DNS takes a few minutes at most and should be doable for everyone.

By using the service you start using the Open DNS servers instead of the ones from the Internet Provider. DNS meaning Domain Name System which is responsible for “translating” domain names into IP addresses.

Open DNS provides additional advantages such as phishing protection (that is not slowing down your computer), parental controls, typo corrections and shortcuts. Shortcuts work like Firefox keywords, you basically assign a phrase to an url and can use the phrase to open the website.

NetCPS – the easier way

This little tool called NetCPS (a single executable file) is rather simplistic, no fancy features as the author (credits to Jarle Aase) says. It pumps 100MB of generated data (without accessing the HDD which could mess with the final result) and then displays the result in form of average speed stated in both KB/s and MB/s. Sourcecode is available for download as well in case you’d like to do some further tinkering with it. Freely usable unless you intend to use it on behalf of military or government.

Example of use:

Server-side end-point: netcps -server
Client-side end-point2: netcps *IP address/hostname of the host*

Additional switches to change the default port (4455) and default amount of transfered data (100MB) are supported. Use the -help switch for further instructions.

Iperf – the powerful way

This tool on the contrary is rather advanced while still maintaining its portability and small size. It can measure performance with many different settings but those are optional and not neccessary for the essential purpose of finding out what the network’s throughput is. You can affect a lot of settings by changing them with various switches. Take notice of the example screenshot for instance, where the port used is changed to 1234, amount of sent data set to 200 MB, interval of reports set to 2 seconds for better accuracy and report format set to MBytes. Iperf can be run as a solid Windows service as well. Here’s a download link to the compiled Windows version of Iperf (a single executable).

Example of use:

Server-side end-point: iperf -s -p 1234
Client-side end-point2: iperf -c *IP address/hostname of the host*

Many additional switches and settings are available for advanced use of this nifty utility. The usual -help switch brings up further instructions again.

As I said it’s pure entertainment. The website seems to be highly popular because it already analyzed more than 380K IPs over the course of several years. My current IP scored a whopping 10 which is bad if you consider that the leading IP received 86 points but not so bad again if you consider that there are negative scores as well with the lowest being -4 currently.

The only two tests that my IP scored was the poker hand where it qualified for a pair (+5) and that it got only even numbers (+5). Users can take a ride with the random IP script and enter an IP manually to see how other IPs are doing on that website or take a look at the leading or last IPs. As I said pure fun for a little while, nothing more.

Many workarounds exist that help users access those services even if they are currently residing in a different country. One possibility that I would like to explain today is to configure Tor that way that the exit node lies in the country that you want to access the service in. Tor offers lots of so called nodes which are servers in a specific country running the Tor software.

I’m using Vidalia, a package that contains all necessary programs, to explain how a specific country can be selected when using Tor. Download Vidalia and install the software afterwards. The main program interface should load after the installation.

The control panel is displaying the current status of Tor. Additional information are displayed which we are going to use to find servers located in the country that we need an IP address from. A click on View the network displays a visual representation of all Tor servers but only if Tor is running.

Servers can be sorted by country flag and do have a performance indicator next to them as well. Write down some server names with the best performance and leave the menu again. We need to add those servers as exit nodes to the Tor configuration. A click on Settings and there on the advanced tab displays a menu where you find the entry Tor Configuration Menu.

A click on browse opens the browse for files dialog. Left-click on the file “torrc” and choose edit from that menu. Now add the following two lines to the configuration, just paste it at the beginning for instance:

ExitNodes server1, server2, server3
StrictExitNodes 1

Replace server1, server 2 and so on with the server names that you have written down in the network display window. Stop and restart Tor afterwards and the changes should have been made.

Now we have to add a http proxy to our browser. Firefox users click on Tools > Options > Advanced Network and there on the button Settings. Select Manual Proxy Configuration and enter localhost and port 8118 there.

You can test if everything is working fine by visiting my IP lookup script which should display a IP from the country that you have selected the servers from.

Peer Guardian already has many IP addresses blocked that are used by the MPAA to spread fake torrents and to record IP addresses of the peers that download the torrents. Blocklist distinguishes the following categories: ads, bogon, edu,game,gov, p2p,phishing, spam and spy. The most important category for most users will be p2p of course and a installed Peer Guardian client will make sure that your client will not connect to the fake torrent clients and IPs. (if they are in the range that is blocked)

You do not need to configure your file sharing application to work with Peer Guardian, everything is done automatically. You can add sites that you definitely need to the allow list to make sure that they will never be blocked by Peer Guardian.

Update:

The Peer Guardian website is currently returning a 404 not found error. It is unclear at this point in time if this is due to technical difficulties or because the project has been canceled. We have uploaded the latest working version of Peer Guardian 2, PeerGuardian 2.0 RC1 Test 2, to our servers.

The blocklist website that is used to manage the blocked IP addresses is not reachable as well currently. This highly suggests that the PeerGuardian 2 project is dead. Still, if you want to download the latest version you can do so by clicking on the following link: Peer Guardian 2 (206)

An alternative is Peer Block

Whenever you try to access a website you type its url into the address bar. The url is then send to the DNS server who looks up the IP for that website and sends it back to your browser to be able to make the connection to the website. To censor one would simply return no IP or a different IP that redirects to another website. (something like, no no, this is no website that you should visit, bla bla)

This means that the website that you want to access exists of course but the information on the dns server was changed to prevent access. There are two options that let you access the website. The first would be to simply enter the IP address of the website that you want to visit instead of the url. You can use scripts that are freely available on the internet to lookup the IP of an url.

This method is only working if there is only one url that is using that IP. You are out of luck if many websites are hosted on the same server. The second method which is reliable and working for all occasions helps us in this case.

If you change the DNS server that your computer is using to lookup the IP you will receive the correct result. Let us say that you life in China and that China banned access to Wikipedia. Instead of using a Chinese DNS server you use one from the United States which has the information that you need to access Wikipedia.

OpenDNS, a free service, would be one alternative as would be the following list which I have taken from freerk.com

• dns2.de.net – 194.246.96.49 (Frankfurt, Germany)
• ns1.de.eu.orsn.net – 217.146.139.5 (Hildesheim, Germany)
• resolver.netteam.de – 193.155.207.61 (Alfter-Impekoven, Germany)
• sunic.sunet.se – 192.36.125.2 (Stockholm, Sweden)
• master.ns.dns.be – 193.109.126.140 (Leuven, Belgium)
• ns1.lu.eu.orsn.net – 195.206.104.98 (Belvaux, Luxembourg)
• merapi.switch.ch – 130.59.211.10 (Zurich, Switzerland)
• prades.cesca.es – 192.94.163.152 (Barcelona, Spain)
• michael.vatican.va – 212.77.0.2 (Vatican City, Italy)
• dns.inria.fr – 193.51.208.13 (Nice, France)
• ns0.ja.net – 128.86.1.20 (London, UK)
• nic.aix.gr – 195.130.89.210 (Athens, Greece)
• ns.ati.tn – 193.95.66.10 (Tunis, Tunisia)
• ns1.relcom.ru – 193.125.152.3 (Moscow, Russia)
• trantor.umd.edu – 128.8.10.14 (College Park, MD, USA)
• ns1.berkeley.edu – 128.32.136.9 (Berkeley, CA, USA)
• merle.cira.ca – 64.26.149.98 (Ottawa, Canada)
• ns2.dns.br – 200.19.119.99 (Sao Paulo, Brasil)
• ns2.gisc.cl – 200.10.237.14 (Santiago, Chile)
• ns.uvg.edu.gt – 168.234.68.2 (Guatemala, Guatemala)
• ns1.retina.ar – 200.10.202.3 (Buenos Aires, Argentina)
• ns.unam.mx – 132.248.253.1 (Mexico City, Mexico)
• ns.wide.ad.jp – 203.178.136.63 (Osaka, Japan)
• ns.twnic.net – 192.83.166.11 (Taipei, Taiwan)
• ns3.dns.net.nz – 203.97.8.250 (Wellington, New Zealand)
• box2.aunic.net – 203.202.150.20 (Melbourne, Australia)

Changing the DNS Server is a matter of minutes. It depends on the operating system that you are using. In Windows XP you open the control panel and click on network connections. You right-click your connection and select Properties from the context menu.

Select the Internet Protocol (TCP / IP) and click on Properties in that menu. Click on use the following DNS server addresses and enter a preferred and alternate DNS server into the fields. Make sure you enter the IPs. Apply and close the menu and restart your computer. Once that is done you are using the new DNS server which should bypass the censorship.

It also has additional features, like NetBIOS information (computer name, workgroup name, and currently logged in Windows user), favorite IP address ranges, customizable openers, etc.

The tool is mainly useful for system administrators who want to take a quick look at their network and see whats going on. Plugins enhance the tool tremendously, for instance there are plugins that detect ftp servers, windows shares and more. Pretty handy tool if you ask me.

In addition, CurrPorts allows you to close unwanted TCP connections, kill the process that opened the ports, and save the TCP/UDP port information to an HTML file , XML file, or to a tab-delimited text file.

CurrPorts also automatically marks suspicious TCP/UDP ports with pink color. These are usually owned by unidentified applications (Applications without version information and icons)

#only 36K, freeware, no system changes, download and run
#runs on all windows versions but older versions show less details

Update:

Nir Sofer has updated the application constantly ever since we first reviewed it here on Ghacks. Users can now select to run a 32-bit or 64-bit version of the application. CurrPorts at its core has remained more or less the same though.

You can start the portable application directly after you have downloaded and unpacked it on your computer. The program then displays a list of all running processes in its interface. The information are updated in realtime, which means that you can use the program to see if applications that you install or start are trying to phone home or opening ports on your system.

The second option that you have is to check for open ports on the PC that should not be open in first place. You can improve your computer’s security by closing those ports as it reduces the number of attack vectors that attackers have. It is still necessary to research how ports are closed, as this is something that CurrPorts does not help you with.

Windows users can download Currports from the official Nirsoft website. Download Currports

Whenever you connect to a website, start a ftp session, write an email or use a chat client your IP address is transmitted. Ip stands for Internet Protocol and is a 32 bit number that is assigned to every computer connected to the internet. 64.202.163.79 would be an IP address.

You can see that it consists of four 8bit octets each separated by “.” ranging from 0 to 255.

The most important question is of course: What does the Ip address tell others about the user behind the IP ?

Most people are not good remembering numbers, that’s one of the reasons why the DNS system, Domain Name System, exists. The DNS turns the IP numbers into textform, there are online tools that do that for you, for example dnswatch.info

If you go to the site and enter the Ip 64.202.163.79 you see that the look up reveals www.ghacks.net, the website you are surfing atm. You could easily exchange www.ghacks.net with the IP and still surf the site, try it if you like.

There are static and dynamic Ip addresses. Static means, the Ip is not changing, most websites have static IPs. Dynamic means it is changing, mostly dialups have these kind of IP addresses.

Now, you probably want to find out about your own ip I suppose ? There are numerous services that display your IP address when you visit their websites, there are scripts e.g in forum signatures that do the same. One website that offers the service: 1. whatismyipaddress.com

If you want to try others simply use Google and search for “what is my ip”

The DNS you find gives you detailed information about the internet provider you use. It sometimes also gives more information, for example a country code clearly shows where the internet provider is located. (for example .de mean Germany, .fr is France aso.)

You can find a comprehensive list of country codes here

Let us look at an specific example. Most of you receive spam mails every day. You normally only see a basic header of the email, giving you basic information like from, to, date and subject for instance. Most mail tools have an option to also display extended header information, that’s where the senders IP address is located.

Here is a typical extended header


Received: from friko7.onet.pl (c-24-20-255-46.hsd1.or.comcast.net [24.20.255.46])
by server6.xlhost.de (Postfix) with ESMTP id D885256215
for [block]3[/block]
To: admin@ghacks.net
Message-ID:
Subject: Account has been created
...


This line “Received: from friko7.onet.pl (c-24-20-255-46.hsd1.or.comcast.net [24.20.255.46])” is the important one. The Ip of the sender is clearly shown 24.20.255.46, so is the DNS c-24-20-255-46.hsd1.or.comcast.net

There are numerous mail tutorials that describe this procedure in greater detail, for now this is all you need to know for our article.

Lets take a look at another example. Maybe you are using an instant messenger and would like to know the ip address of the people you are chatting with. On Windows XP, select START, then run. Enter “cmd” and then “netstat -n” to see a list of all your active connections.

To receive a IP address you need to have a session open with someone, private chat, file transfer etc.. If you do the netstat command without a session you only see the IP of the server that you are connected to, you simply do not need to know the Ip addresses of the other users who are connected until you communicate with them directly.

This have been two examples, I could give you more (for websites, IRC, Bittorent) but that’s not part of this tutorial.

What have we learned so far ? Everything you do on the internet also transmits your IP Address.

Your next question probably is the following: If someone has my IP how can he find out more about me ?

As we have seen the DNS lookup gives you information about the provider. They could easily file a complaint at your provider that your IP did the following at a specific day and time.

Or, they could hire a lawyer in your country and file a complaint against the user that used the IP at a specific day and time. They normally don´t know your name until a law enforcement agency asked the provider for all the details they have about this IP at the given time. I can´t speak for every country but for the moment most providers only give out specifics about their users when a law enforcement agency asks for the information.

To clear things up a little bit. Your provider has logs for x days. These logs show at least every IP address assigned to users with information how long the user was online. If someone complained against you the provider simply would search for the specified Ip address in their logs and get all the information about the user behind the IP.

I suggest you ask your provider for how long the logs are stored. Mine for example stores them only for a maximum of 24 hours, but I heard of some that save them for up to six months.

That means, for as long as your internet provider has your connection information in their logs someone could find out about you.

I hope you found the information provided useful, I will write an anonymity tutorial soon.

Technorati Tags: Ip, Address, Anonymous, Email, Header, DNS