The configured DNS server basically tells the web browser where to look for when a web address such as www.ghacks.net is entered into the browser’s address bar. If that lookup is manipulated part or all of the page elements of the website can be replaced by the operators of the rogue DNS server.

The FBI back then replaced the DNS servers that the cyber criminals used with working servers to avoid interruption of service for users affected by the DNS server change.

These DNS servers will however be shut down on March 8th, 2012. Affected users from that day on may not be able to connect to Internet addresses anymore until they replace the DNS server with working ones.

Security company Avira, famous for their antivirus solution, has released the Avira DNS Repair-tool.

You can run the portable program on your system to see if your computer’s DNS server has been manipulated by DNSChanger.

The program will reset the DNS servers to Windows default values if it finds out that they have been manipulated by the malware.

It is alternatively possible to check for manipulation manually.

Use the shortcut Windows-r to bring up the run box. Enter cmd in there and tap on the enter key to open the command prompt. Now run the command ipconfig /all and locate the DNS Servers entry. Compare what you see there with the list of rogue DNS servers below

• 64.28.176.0 – 64.28.191.255
• 67.210.0.0 – 67.210.15.255
• 85.255.112.0 – 85.255.127.255
• 77.67.83.0 – 77.67.83.255
• 93.188.160.0 – 93.188.167.255
• 213.109.64.0 – 213.109.79.255

If your DNS server IPs differ from the ones above then congratulations, you are not infected. You otherwise need to change the DNS server. While you could do that manually, you may prefer to use a program for that. You can use the Avira tool to reset the DNS Server, or a program like DNS Jumper to select a public DNS server instead.

You can download the Avira DNS Repair-Tool from the official Avira website

Some ISP’s highjack domain queries with typos to earn additional revenue from the user. Others might block website access with the help of the DNS system.

Public DNS servers can be an alternative. Common ones are Open DNS, Google DNS or Norton DNS among others.

They often offer features that the ISP dns servers are not offering. This may including blocking of advertisement or tracking related scripts, or parental controls to protect minors from Internet threats.

Experienced computer users should not have issues changing DNS servers on their computer. Inexperienced users on the other hand might prefer to use a tool that automates the process.

Public DNS Server Tool is a free portable program for Windows that can change the DNS server of installed network cards. It is similar to DNS Jumper which can also be used for the purpose.

It takes two clicks after program start to change the DNS server. You need to select a network card first if multiple cards are installed on the system. You can ignore the network interface card pulldown menu otherwise.

A click on the public dns servers menu displays the list of supported services. This includes Google DNS, Open DNS, Norton DNS, Comodo Secure, ScrubIt DNS and DNS Advantage. Just select one of the providers from the list and click on change afterwards to use the new DNS server from that moment on on the system.

You can alternatively change the IPs directly in the current DNS servers listing.

The program is not displaying information about the providers, which may make it necessary to do some digging of your own. You may also like to use the DNS Server benchmark tool to test the connection speed.

Windows users can download the Public DNS Server Tool from the developer website. The program is compatible with 32-bit and 64-bit editions of the operating system.

The developer recently has released DNS Jumper version 1.0.4. The new version shows many improvements justifying a new review here on Ghacks.

When you start the program now you will notice that it looks completely different from the version reviewed in 2009. You can select one or all network cards of the computer system in the pulldown menu at the top. A refresh button is available to scan for new network cards.

The Choose a free DNS Service menu lists dozens of DNS providers. If you select a provider from the list you will see the IP addresses of the servers in the program interface. Even better, you can click on the check response time button to benchmark all domain name servers listed in the application.

You can add DNS services manually to the list of providers with a click on the + icon in the interface. All you need to do then is to enter a DNS Server Name and the two server IP addresses.

Another interesting feature is the ability to benchmark all servers for speed. A click on the Fastest DNS button runs the benchmark (again) with the option to switch to the fastest server in the end.

A click on Apply DNS sets the currently selected DNS Service as the DNS provider for the selected network adapter. The program can backup the settings to restore them at a later time and flush the DNS.

The developer has improved the program noticeably by correcting the issues of the old version. Windows users can download the portable freeware DNS Jumper from the developer website. The program is compatible with 32-bit and 64-bit editions of the Windows operating system.

Selecting the right third party DNS provider should require at least some research on the user’s part to find the best suitable server. A user in the US for instance would not necessarily want to pick a European DNS provider and vice versa. Another aspect that plays a role besides speed is the legal situation if a DNS provider in a foreign country or by a foreign company is selected. Plus, you may get extras like options to filter out spam or specific types of sites automatically.

DNS Benchmark is a free portable software for the Windows operating system that can be used to test the speed of multiple DNS servers. The program ships with dozens of pre-added servers that include Google DNS and Open DNS among others. The program comes with options to add or remove particular domain name servers from the listing.

A click on run benchmark runs a series of tests that include name and owner look-ups, status messages and the response time. The latter is further divided into cached and uncached response times.

You can switch to a tabular data view which offers minimum, average and maximum values as well as a providers reliability in percentage.

The program works best for users who have found a few prospective DNS providers on the Internet. These users would add the server IPs of all prospective domain name servers to the DNS Benchmark software to test their speed and reliability.

Speed is of course only one of the variables that computer users need to look at. Interested Windows users can download DNS Benchmark from the official developer website. The program is compatible with all recent 32-bit and 64-bit editions of the Microsoft Windows operating system. An alternative is the previously reviewed Namebench.

Over the years, I developed a technique on how to best move a website to a new server. I’m using it ever since and it has resulted in 0 downtime or difficulties when moving a site to a new host.

Here is the list of data and information that you need to get started:

• Old and new ftp server logins.
• CPanel or web hosting logins from both the old and new web host.
• MySQL logins, MySQL user and database information.
• Website admin interface logins.
• Logins for the old and new web hosting company.

This is the step by step guide on how to move the site to a new server:

Download all data

My first step is always a full backup of all site data. This includes the web files and databases. I often connect to the ftp server and download the web files to my local computer, and use Cpanel or a comparable hosting panel to create the database backup. This step can take some time. But we can prepare the new hosting account in the meantime.

Setup the new hosting account

I start to configure the new hosting account while the data is downloading. This includes basic setup of the account, quotas, ftp login, MySQL database and user among other things. I do that to have the data at hand to proceed to the next step immediately after the data backup completes.

Upload the data

Once the downloads are finished I begin to upload the data to the new host. I use the same ftp client to upload the data to the new host, and Cpanel or phpMyAdmin to import the MySQL database.

I also modify the data if needed. This may include the new MySQL database information or paths in configuration files.

Hosts File Changes, Testing

I edit the Hosts file on my system to point to the new server IP address. This is done for testing purposes. Remember that you cannot access the domain name on the new host at this point in time, since the nameservers are still pointing to the old hoster. Check out Work On Websites Before DNS Propagation for a detailed guide on how to change the Hosts file for that purpose.

Once the Hosts file has been changed, it is possible to access the site with its domain name on the new server. Just enter the domain name in your web browser to do that. I test the new site extensively, check that everything is displayed correctly and that no error messages show up. I also test the admin interface if available to make sure that it works as well. If you are unsure, ask a friend to take a look at the site to see if you have overlooked anything.

Switch Nameservers

If the website passes all tests I open the domain hosting panel at the domain registrar and switch the nameservers so that they now point to the new web server instead of the old one. The propagation may take up to 48 hours to complete. I suggest you test the connection with proxies or virtual private networks for testing purposes.

I keep the data on the old domain name for at least a week or two. I also backup the downloaded data to have it at hand if I should need it.

It pays to monitor the traffic and web servers during the propagation phase to make sure that the process is fluent and without service interruption.

Have you ever moved a domain name to a new web hosting account? If so, tell us about your experience.

The software is a free portable application. Just unpack it after download and run the executable afterwards. You get two windows on first launch, a select domains window that resembles a text editor and the main program window. Add domain names to the select domains window and pick the DNS record types that you want to look-up.

Four additional options are available.

• Use the following DNS server – Lets you select a different DNS server, for instance Open DNS, Google DNS or another public DNS server for the DNS look-ups.
• When IP address is detected, retrieve the PTR record (Reverse DNS lookup) – It is possible to enter IP addresses in the domain list. If this option is enabled, a reverse DNS lookup will be performed to retrieve the IP addresses’ host name.
• Show error information when DNS record cannot be retrieved – Displays errors when a DNS record lookup fails.
• Filter out additional records – Only display the selected records, do not show additional records.

Dns Data View retrieves information about each domain name and IP address. All information are displayed in a table like interface in the main program window. Among the information are the domain name, DNS record type, host name or IP address.

The entries can be sorted with a click on one of the table headers, for instance by IP address or host name.

A HTML report can be generated for selected items or all items. It is furthermore possible to export the data to a text, XML, HTML or comma delimited file.

I see two core applications for DNS Data View. First to verify that DNS records are properly configured for one or multiple domain names, and second to check DNS propagation by using different DNS servers.

DNS Data View is a portable software for all recent versions of the Windows operating system from Windows XP to the latest Windows 7 version. It tested fine on a 64-bit Windows 7 Professional system.

Interested users can download the program from the Nirsoft website.

Not every DNS server is equal on the other hand, and it is not only a performance question either. Performance on the other hand plays a big role and it is quite possible to speed up the connections on the Internet by switching to a better performing DNS server.

Besides speed, it can also benefit the freedom of speed and other functionality. Internet Service Provider, the state or organizations make use of the DNS system to block access to websites and services on the Internet. It is not a foolproof protection but it has the effect that the DNS server resolves to a different IP, or none at all so that the website cannot be accessed by entering its domain name in the browser. That can be easily bypassed with anonymous proxies, virtual private networks, entering the IP directly or switching the DNS server.

Some DNS providers add filters and blocklists to their services as well, for instance to block known malicious websites automatically in order to protect their users. Open DNS does that for instance.

DNS Performance Test is a free tool for Windows, Macintosh and Linux that queries a random set of 10,000 urls to determine a DNS server’s mean query time. The list is generated randomly on startup, the only available option for the user is to start the performance test.

The DNS test takes time to complete which should be clear as each connection can take anywhere between 10 and a few thousand milliseconds.

Statistics are displayed on the Stats tab. They can be accessed even while the performance test is still running. It shows the best, worst and average query time, the number of successful queries, the timeouts and gives an assessment of the overall DNS server performance.

If the DNS server performance is bad it may make sense to try another DNS server provider to see if the situation changes. This would mean that the DNS performance test needs to be run again before the results can be compared.

DNS Performance Test is available for download at the developer website.

Most Internet users use their Internet Service Provider as the DNS provider, often without their knowledge. This may not always be the optimal solution depending on the provider’s infrastructure, network speed and handling of domain names that cannot be resolved as well as a country’s censorship implementations.

The last two aspects might need some clarification. Many IPSs display custom search pages if a domain name cannot be resolved. They do that to cash in on the user’s searches. This can be frustrating to the user who might want to prefer a different handling of those page requests.

Some countries use the domain name system to block access to web contents and other resources.

Using a different DNS provider can speed up domain lookup times, reduce web censorship and block custom error pages by the Internet providers.

Symantec is the latest company to enter the DNS provider market with Norton DNS which is currently offered as a public beta. The easiest way to use the settings is to change the DNS settings to: 198.153.192.1 and 198.153.194.1.

Symantec offers in depth instructions for Windows and Mac OS X on the official Norton DNS website.

Norton DNS promises the same advantages that Google offered when they introduced Google Public DNS back in December of 2009.

Norton DNS Public Beta offers you a faster, safer, and more reliable Internet experience.

The Norton DNS website and FAQ do not contain lots of information about how it is faster, safer and more reliable than the standard DNS provider. Norton seems to be using information from Norton Safeweb to block malicious site requests automatically. Similar services are offered by other DNS providers such as OPEN DNS as well.

Symantec seems to have plans to expand the product in the future naming parental controls in the FAQ as one of the planned features. It is likely that the service will get integrated into Symantec and Norton products once it comes out of beta.

In this article I will show you how to find out various networking information on your Linux system. All of these tasks can be handled by any skill level of user, so don’t think you have to be an ubergeek, hacker-type in order to gain this information.

IP Address

Figure 1

Let’s start off with the IP Address. Of course, before you do anything, you need to open up a terminal window. Once you have that open you can then issue the necessary command. The command for finding your IP Address is ifconfig. When you issue this command you will receive information for every network connection you have available. Most likely you will see information for both the loopback (lo) and your wired network connection (eth0). If you have a wireless connection that will be listed, most likely, as wlan0. The reported information will look like that shown in Figure 1. As you can see, you not only get the IP Address, but the Broadcast address, the Subnet Mask, and the IPv6 Address.

Hostname

From that same command line, if you enter the command hostname you will see the actual hostname of your machine. In the case of my test machine, I see Ubuntu-desktop.  For more information on using this command, take a look at my article “Set your hostname in Linux“.

DNS Address(es)

There is no actual command to see your DNS addresses. You don’t really need one. All you need to do is examine the /etc/resolv.conf file with the command less /etc/resolv.conf, at whichpoint you will see something like:

nameserver 208.67.222.222

nameserver 208.67.220.220

Gateway address

Figure 2

Now let’s find out what the Gateway address is. The command used for this is the netstat command. This command does quite a bit more than just discover your gateway. What the netstat command does is print network connections, routing tables, interface statistics, masquerade connections, and multicast memberships. But to find the gateway address you would issue the command netstat -nr and you will see something like that shown in Figure 2. You can probably guess it, but the Gateway address is 192.168.1.1. The flags you used in that command are n (for numeric addresses) and r (for route).

Of course the netstat command can do much more than that (we’ll cover that in another article).

Final thoughts

Yes, there are a lot of tools that can be used in Linux. It all depends upon how you want to get your information. In both the GNOME and KDE desktops there are outstanding GUI tools you can use for all of this. But knowing the command line route makes you much more versatile.

While it is not difficulty to change the DNS servers in the operating system it does require some knowledge as to where they are changed. And the IP addresses of the DNS server need to be known as well to apply the changes to the computer system.

DNS Jumper is a free and portable software program that aids the user by providing a one-click system to change DNS servers in Windows. The application displays a list of DNS servers that can be activated with the click of the mouse button. Available DNS server range from Google DNS over Open DNS to Ultra DNS, Level 3, Open NIC to the default DNS server of the system.

Changing DNS servers is therefor a breeze with DNS Jumper. The program does on the other hand lack relevant information and a configuration to edit the available DNS servers. DNS Jumper can be downloaded from the the Fiber Download website (via ASK VG)

Namebench is a free and portable software program for Microsoft Windows, Linux and Apple Macintosh computers that can perform these DNS benchmarks for the user. The program will automatically discover the DNS servers that are currently used by the connections and add those to a list of available public DNS servers. The computer user has furthermore the chance to add further DNS servers to the benchmark.

Namebench will then take website samples from a web browser’s history file. It will by default pick the web browser with the largest history giving the user the choice to switch to another web browser in the benchmark preparations. The number of tests and the number of runs can be configured in the interface as well.

The test can take some time which largely depends on the number of runs and tests but also on the number of DNS servers that have been added by the user to the program. Namebench will then calculate the best nameservers and generate a local webpage with the test results.

The performance increase (or decrease) along with the nameservers that need to be configured for it are displayed on top of the report.

A detailed report follows that displays the test results of the tested DNS servers. This includes their IP, average, minimum and maximum response time, errors, no answers and notes.

Various graphs are displayed in the end that display the response times of the tested DNS servers.

Namebench can be downloaded from it’s Google Code project page. (via Download Squad)

The Internet Service Provider is usually the one that is providing the DNS servers to the customer. This happens more often than not automatically. There are however reasons to switch to other DNS servers with performance, privacy and censorship being three of the major reasons.

Censorship: Some countries use DNS to block access to websites. This is a weak block that can easily be bypassed by the user by entering the IP address of the website instead of its domain name.

Privacy: Many ISPs cash in on domain typing errors by displaying a custom error page to the user instead of the simple “page not found” error page.

Performance: Some ISPs offer DNS servers that are not optimized, slow and sometimes even unreachable.

Users who experience some of these difficulties can switch DNS servers. One of the most prominent free DNS providers was Open DNS which not only offers a fast independent DNS system but also additional optional values that include phishing and web content filters.

Google today announced that they have started offering public DNS servers as well. The system, called Google Public DNS, was designed to “make users’ web-surfing experiences faster, safer and more reliable”.

Speed: Resolver-side cache misses are one of the primary contributors to sluggish DNS responses. Clever caching techniques can help increase the speed of these responses. Google Public DNS implements prefetching: before the TTL on a record expires, we refresh the record continuously, asychronously and independently of user requests for a large number of popular domains. This allows Google Public DNS to serve many DNS requests in the round trip time it takes a packet to travel to our servers and back.

Security: DNS is vulnerable to spoofing attacks that can poison the cache of a nameserver and can route all its users to a malicious website. Until new protocols like DNSSEC get widely adopted, resolvers need to take additional measures to keep their caches secure. Google Public DNS makes it more difficult for attackers to spoof valid responses by randomizing the case of query names and including additional data in its DNS messages.

Validity: Google Public DNS complies with the DNS standards and gives the user the exact response his or her computer expects without performing any blocking, filtering, or redirection that may hamper a user’s browsing experience.

A Google Code page details how to change the DNS servers to use Google Public DNS servers. Experienced users need to use the following two DNS servers.

8.8.8.8
8.8.4.4

Privacy Concerns

But what about Privacy? Users who use the Google Public DNS servers will automatically submit extensive data to Google that includes all the websites and other services on the Internet that they visit.

According to the privacy information posted on the project web page Google Public DNS records temporary and permanent data but does not “correlate or combine” these information “with any other log data that Google might have about your use of other services, such as data from Web Search and data from advertising on the Google content network”.

Temporary Logs: The temporary logs store the full IP address of the machine you’re using. We have to do this so that we can spot potentially bad things like DDoS attacks and so we can fix problems, such as particular domains not showing up for specific users. We delete these temporary logs within 24 to 48 hours.

Permanent Logs: In the permanent logs, we don’t keep personally identifiable information or IP information. We do keep some location information (at the city/metro level) so that we can conduct debugging, analyze abuse phenomena and improve the Google Public DNS prefetching feature. After keeping this data for two weeks, we randomly sample a small subset for permanent storage.

Verdict:

Some users will say that providing public DNS servers is just another step in Google’s world domination plans. Others might find out that the benefits outweigh the doubts and concerns. It is definitely not bad to have another option in this field especially with the increasing censorship around the world.

This can be problematic for webmasters who face the same DNS propagation wait time especially if they want to make sure that the website works fine at the new hosting location. There is one easy way of accessing the website at the new web server even if the DNS is still pointing to the old: The Hosts file.

The Hosts file can be used to map a domain name to an IP address. All that needs to be done to work with a website before DNS propagation is to map the domain name to the new IP address. Here is how this is done in the Windows operating system.

The Hosts file in Windows is located at C:\Windows\System32\drivers\etc\Hosts

You might need to change the rights of the current logged in user first so that the file becomes writable.

All you should see when opening the Hosts file with a text editor is a comment section on top unless someone else has already added new entries to it.

New entries to the Hosts file can be added after the last line. To do that add the IP address of the new server and then the domain name of the website like 96.30.22.116 acerliquid.net with a blank in between. All programs of the operating system will now open the website using the new IP address even if the DNS servers are still routing to the old server. This gives webmasters an excellent opportunity to edit these websites before the DNS propagation has finished.

Users who try to flush the dns cache might receive the error message “Windows IP Configuration Could not flush the DNS Resolver Cache: Function failed during execution” if the DNS Client service is deactivated.

The solution to fix this error message is to enable the DNS Client service again in the Services configuration menu. I’m not sure if it makes that much sense to flush the cache if the DNS Client is disabled as it should mean that Windows is not resolving and storing DNS at all. Experts who might to weight in are encouraged to do so.

You can start the service by typing [Windows R], [services.msc] [enter]. Locate the DNS Client service, right-click it and select properties from the menu.

You need to set the service to manual or automatic before you are able to start the service.

Naturally if you have such a server, you have to have the ability to configure that server. One of the configurations you most likely will need to undertake is the configuring of network settings for a static IP address on your headless, GUI-less server. Fortunately, when using Ubuntu Server 8.10 – that is a piece of cake.

In reality there are two files that must be configured and one file that can be configured. The “must files” are /etc/network/interfaces and /etc/resolv.conf. The “can file” is /etc/hosts. We will deal with the former two files in this article. The latter file (a file that deals with local IP to name mapping) has already been covered in my article “Ease Linux Networking with /etc/hosts” here on gHacks.

So let’s first take a look at the most important file, /etc/network/interfaces. Open that file up in your favorite editor (mine being nano).? What you will most likely see is this:

# This file describes the network interfaces available on your system
# and how to activate them. For more information, see interfaces(5).
# The loopback network interface
auto lo
iface lo inet loopback
# The primary network interface
auto eth0
iface eth0 inet dhcp

The last line is what you need to edit (and add to.) To configure eth0 (your network device) for a static IP address that last line should resemble:

iface eth0 inet static
address 192.168.1.10
netmask 255.255.255.0
gateway 192.168.1.1

Naturally you will need to change the last three lines to reflect your own networking setup.

Once that file has been edited you can restart your network connection with the command:

sudo /etc/init.d/networking restart

Your Ubuntu Server 8.10 should now be up and running with a static IP address.

DNS

There is one last file you will need to take care of. That file is /etc/resolv.conf. This file is in charge of holding your DNS server addresses. Open this file up in your editor. What you need are two lines:

nameserver 208.67.220.220

nameserver 208.67.222.222

The above example reflects using the OpenDNS servers. Your network will obviously have its own requirements for DNS addresses. Once you have edited that file save it and you’re done (no need to restart networking for the change in DNS addresses to take effect.)

Final Thoughts

That’s it. How simple is it to configure your Ubuntu Server with a static IP address – even when said server is a headless, GUI-less server. Of course there is much more you can do than simple Static IP address configuration, but this just highlights how easy a Linux server can actually be to administer.

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.

Those lookups are handled by dns servers and recently a serious vulnerability has been discovered that makde it possible to manipulate those queries. This could be used to send users to a different location which could open the door for serious phishing incidents. Just think about the possibility to fake eBay or Amazon and send visitors to those fake sites even if they type in the real address.

Doxpara Research, run by security researcher Dan Kaminsky, created a script that is checking if the DNS server that you are currently using is vulnerable to the attack. This is done by pressing a button on their website. I tested the script in Firefox and Internet Explorer and both lookups work fine.

One solution if the DNS server is found to be vulnerable would be to switch to the Open DNS system. David Bradley, an active reader of my website, covered the topic as well on his Significant Figures website.

Is your DNS server still vulnerable? Let me know!

Free IP Switcher [via Tech Malaya] is the perfect tool for this situation. It offers a one click change of the network settings that require no reboot. Probably the fastest solution if you connect to different networks regularly.

What I really like is the feature to import the current network settings which spares you from the hassle to add them to the IP Changer as well. Different IP settings are available in tabs in the program and it only takes two clicks to activate another configuration.

The program offers several additional settings that can be added if needed besides the obvious ones like IP, DNS and Proxy. The Computer Name and the Workgroup can be changed as well as the default printer of the system. Last but not least it is possible to set the DNS Domain and a Wins Server.

Checking if a website is up or not should be speedy, you do not want to waste your time analyzing large log files if there is another faster way to accomplish the check. This article is therefor concentrating on methods that reveal results in a matter of seconds which are easy to interpretate.

If you know of a method that is missing let me know and I will check it out and add it if it makes a good fit. On we go with ways to check if a website is really down.

1. Ping

A ping basically sends an Hello to a server waiting for an response. If the response takes to long a timeout will occur. Ping is measured in ms, if it is incredibly high something is wrong with either your computer, the route in between or the destination.

The command is similar in Windows and Linux, just enter ping destination, with destination being an IP or domain name, and wait for the response.

One of the many online scripts that ping servers is located at Ping.eu. It offers other network tools like Traceroute and a port check as well.

2. Traceroute

You can compare Tracerouter with a list of all the roads that you travel until you reach your destination. Only that the roads are the servers in this case that your data is send through to reach their destination. If everything is fine the destination server should appear at the end, if it is not you could get timeouts for instance.

Traceroute Tool from the University of Princeton displays the traceroute between the University and another server on the Internet, you can enter the IP or domain name of the server.

Tracert is the command that you can use in Windows to trace the route between your computer and the destination. Use the command “tracert IP” or “tracert domain” to achieve this. Traceroute is the equivalent in Linux.

3. Domain Name System (DNS)

DNS errors most of the time occur when a website is freshly registered or moving to another server. It usually takes some time to update the DNS records to point at the new server. DNS is providing information much like your phone book is. Domain names are for us puny humans who have troubles remembering those server IP addresses (64.233.161.18 for Google for instance). Problems occur when the Nameservers who translate the human entered domain names into IP addresses have still the old IP in their records while the website is already up and running on the new IP.

You can use the online script DNS Report to receive a detailed report. Green results are fine, red ones point to failures and yellow ones are warnings.

4. Proxies

Proxys can be used to establish connections to websites even if the direct route from your computer to theirs is somehow blocked. You can compare that to visiting a friend and using his computer to connect to a server that you cannot connect to. If it works it is somehow related to your computer or connection.

You can find hundreds of web based proxies at Proxy.org. Try some and see if you can connect to the website.

5. Ask someone

If you have direct contact to other users, be it in IRC, Skype, Instant Messengers or even forums, you can ask them if they would be kind enough to check a particular website for you. That`s practically a substitute to using a proxy.

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.