Features :

• Performance – Both GPDNS and OpenDNS employ quite a number of tweaks to increase performance of the end users. Both load balance user traffic and implement “smart” caching techniques to speed up domain resolution.
  While this does not directly affect performance, OpenDNS has a nifty tool called CacheCheck, which can be used to check the status of a domain in OpenDNS’s cache and optionally update the domain’s DNS records in the cache. This does score some brownie points for OpenDNS.
• Security – Even though Google Public DNS has protection against cache-poisoning, DOS and amplification attacks, it blandly admits that it doesn’t provide any content-filtering/anti-phishing/anti-malware protection.  Google says :
  

  Google Public DNS is not a malware-blocking service. Google Public DNS does not perform blocking or filtering of any kind

  However, OpenDNS delivers a lot in this sector. In addition to protection against cache-poisoning and other vulnerabilities, it offers web-content filtering, “PhishTank” anti-phishing, malware-protection and whitelisting/blacklisting of domains, all though a web-based dashboard. In addition to this, OpenDNS also features a community based domain tagging system, where users can tag domains into appropriate categories and check the status of an already-tagged domain.

Real-world Performance

I used Namebench to perform DNS benchmarks. The results are as follows:

Mean Response Duration

Fastest Individual Response Duration

The tests proved that Google Public DNS resolver is 5% faster than the OpenDNS resolver.

Conclusion

Even thoughthe real world test found Google Public DNS to be 5% faster than OpenDNS, it actually makes a very little difference in speed. Considering the advanced features like anti-phishing, anti-malware, content-filtering and custom-error pages, OpenDNS is recommended for both network administrators and end users.

Special Note :

Google says that it shows correct results for NXDOMAIN results, ie, due to mistyping or otherwise, if a non-existent domain is tried to be resolved, it will return an error message. OpenDNS, however, redirects such requests to it’s search page where it shows similar domains along with some sponsored links. I couldn’t decide whether this is a good or a bad move, so I didn’t include this in the evaluation process.

No related posts.

• Step 1 :

First, add your domain to the control panel of your new host. This way, you’ll ensure that their name servers are updated with your domain’s information, when you point your domain to your new host.

• Step 2 :

Put your site in read-only mode or maintenance mode. This way, you can ensure that your content do not change while you shift your files. Put up a short message informing visitors of the shifting of hosts. If your site consists of static HTML files, you do not need to worry about this.
Note : Most forums have an option for turning on the maintenance mode. For a Wordpress blog, you might consider using the Maintenance Mode plugin.

• Step 3 :

Next, backup everything : your databases, files. If you use cPanel, use the Backup feature to backup your files and databases. You might also request your current host to backup your databases and files for you and they should probably do it. You can also manually download all your files using an FTP client and backup your databases with tools like phpMyAdmin.

• Step 4 :

Now upload the files into your new web host’s webspace. Most hosts provide a way of uploading your files and databases and view your site before the DNS changes propagate. However if your host does not provide you any such a way, you can take help of a little trick.
Note : This would not work unless you have performed the instructions in step 1 of this guide.

Take a note of your new host’s name servers. Let’s say, they are ns1.newhost.com and ns2.newhost.com. Now let’s query those name servers about your domain using the nslookup utility. Go to Start>Run and type in the following :

nslookup yourdomain.com ns1.newhost.com

Replace yourdomain.com with the name of your domain.
The query should output something like this :

Server: ns1.newhost.com
Address: XXX.XXX.XXX.XXX

Name: mydomain.com
Address: 1.2.3.4

Take a note of the IP address of mydomain.com. Now, go to ‘C:\WINDOWS\system32\drivers\etc’ and open the file named ‘hosts’ with a text editor. On a new blank line, add the following lines :

1.2.3.4    yourdomain.com
1.2.3.4    www.yourdomain.com

Replace yourdomain.com and 1.2.3.4 with their real-life equivalents.

Now your domain will be pointed to the IP address of your new host’s server only for you. Now you can upload your files, databases to your new host using yourdomain.com as the URL. After uploading everything, check whether your site is looking as it should and whether it’s generating any errors. If there is any errors or discrepancies, correct them. You should make a minor, but noticable change to your index file at your new host so that you can know if the DNS changes have propagated. After this you should remove the two lines from the ‘hosts’ file that you previously added to it, so that the domain resolves to your old host.

• Step 5 :

Now it’s time to change the DNS record of your domain. First we have to check if your new host’s name servers have been updated with records of your domain. For this, we need to run an nslookup query. Go to Start>Run and type in :

nslookup yourdomain.com ns1.newhost.com

If the query returns a non-authoritative answer or a “*** UnKnown can’t find yourdomain.com: Server failed” result, then your new host’s name servers haven’t updated yet. Use the same nslookup query to query the name servers again after some time. Repeat this process until it doesn’t return a non-authoritative answer or gives errors for your domain name. Usually, a name server updates itself every 15 minutes, but there may be exceptions. Now it’s safe to change your DNS records. Change your name servers to that of your new host’s OR change your A records to point your domain to your new host’s server’s IP, whichever you wish. The DNS changes will take around 24 to 48 hours to propagate around the world. You’ll know that the changes have propagated when you notice the minor change in your website which you did in Step 4.

Don’t delete your old hosting account yet. Until the DNS changes propagate around the world, people will go to your site hosted at your old host. It’s usually safe to delete your old hosting account after 5 days.

This pretty much concludes this article. If you face any problems while following the steps above, leave a comment and I’ll gladly help you.

See also : Automated website tools.

Related posts:

1. A guide to DNS
2. WWW or no-WWW?

It’s quite simple actually. Say you want to set up a sub sub domain sub2.sub1.domain.com. All you need to do is create an A record for sub2.sub1.domain.com and point it to the required IP(the IP of the server hosting the sub sub domain). If you want www.sub2.sub1.domain.com to work(not required in most cases), you should create another A record for www.sub2.sub1.domain.com and point it to the same IP. This can also be done using a CNAME record.

So, if the server that is going to host your sub sub domain has IP 1.2.3.4, your DNS records should be like this :

sub2.sub1.domain.com.       A     1.2.3.4
www.sub2.sub1.domain.com.   A     1.2.3.4

If you want to use CNAME records :

sub2.sub1.domain.com.       A       1.2.3.4
www.sub2.sub1.domain.com.   CNAME   sub2.sub1.domain.com.

There may be a lot of reasons why someone would want to use a sub sub domain; the most important of them being forming meaningful(or desired) words/phrases out of a domain name. One of the most popular example of a site on a sub sub domain is www.Del.icio.us. It clearly illustrates the usefulness of a sub sub domain.

Related posts:

1. A guide to DNS

The most dreadful situation is when your DNS is set up incorrectly. Most webmasters dread the thought of incorrectly configured DNS, as they can’t figure out where they went wrong. But troubleshooting DNS problems is very easy, considering you know how to use tools like nslookup, dig, bind, etc. Before we go into tutorials, it would be a good idea to look up the various types of DNS records at Wikipedia.

Here we’ll be discussing about various scenarios faced by domain name owners while configuring their DNS.

• Subdomain needs to be hosted on another host/IP
• Your registrar or host doesn’t let you manage your DNS
• Set up a subdomain or a sub-subdomain

Scenario 1 : You need to host a sub-domain on another host or on a different server with a different IP

First you need to add your sub-domain, say “flavour.mydomain.com” to the control panel of the other host, so that they can add your domain their name-servers and create the required A records. Next, you need to know from your new host, the IP address of the server on which your sub-domain is going to be hosted. Say it is “1.2.3.4″. Now you need to go to your DNS management console of your domain registrar/host and create A records for that sub-domain pointing to the IP address of the server of the new host. So, your DNS records should look like this :

flavour.mydomain.com   A   1.2.3.4
www.flavour.mydomain.com   A   1.2.3.4

Add the second A record only if you want www.flavour.mydomain.com(a sub-sub-domain) to work. It is always a good idea to add records for “www.flavour.mydomain.com” and then 301 redirect all traffic from “www.flavour.mydomain.com” to “flavour.mydomain.com”.

The above effect can also be achieved by using a CNAME record instead of an A record, but using a CNAME record is not recommended because of theoretical overhead issues. But if you want to do what’s not recommended, add a CNAME record pointing “www.flavour.mydomain.com” to “flavour.mydomain.com”; so that the DNS records looks like this :

flavour.mydomain.com   A   1.2.3.4
www.flavour.mydomain.com   CNAME   flavour.mydomain.com

Give some time for the DNS changes to propagate(Usually around 30 minutes) and start using your sub-domain right away.

Scenario 2: Your registrar or host doesn’t let you manage your DNS

First of all, I’d recommend transferring your domain from the registrar/moving away from host which doesn’t allow you full DNS control. But if you are hard bound to stay with them, there is still hope for you. There are a lot of 3rd party DNS hosts who would host your domain’s DNS for free. Some of the most popular ones are EditDNS and Afraid.org, but there are quite a few other free DNS hosts which are equally good. I’ll be using EditDNS for this guide.

First of all, register with an account with EditDNS. After signing into your account, navigate to your Control Panel and add your domain(say “mydomain.com”) without www. In the “Default IP” box under Optional Settings, enter the IP address of the server which hosts your domain.

Click on “Add domain”. After adding your domain, you’ll see that your domain name is written in red. Don’t worry, this is perfectly normal. It’ll go back to normal after you change your name servers to that of EditDNS’s and the changes propagate. Now, click on the “Edit” icon beside “mydomain.com”. You’ll come to a page that looks like this :

Take a note of the name servers (highlighted in red).

List of nameservers (US only) :

• ns1.us.editdns.net
• ns2.us.editdns.net
• ns3.us.editdns.net

List of nameservers (EU only) :

• ns1.eu.editdns.net
• ns2.eu.editdns.net

List of nameservers (EU+US) :

• ns1.us.editdns.net
• ns2.us.editdns.net
• ns3.us.editdns.net
• ns1.eu.editdns.net
• ns2.eu.editdns.net

To change between US/EU/EU+US name servers, click on the corresponding link after “Change NS: ” in the “Additional Services” section. I’d recommend changing to EU+US name servers because it will be more fault-tolerant and your domain will resolve faster across the globe.

Now you need to go to your DNS management console of your domain registrar/host, delete all name servers and add the EditDNS’s name servers. Now, let’s go back to EditDNS’s DNS management. To add a record, type in the record name, select the type of record (A, AAAA, CNAME, MX, SRV, TXT, PTR) and type in the IP/Hostname. Don’t change the AUX and TTL values unless you need to. A TTL value of 86400 seconds is enough for your domain. To edit a DNS record, double click on it, make the necessary changes and click on “Save”.

Scenario 3: Set up a subdomain or a sub-subdomain

To set up a sub domain, simply create an A record for the subdomain and point it to the IP of server on which it is to be hosted.

For example, if you want to create a subdomain called vanilla.mydomain.com to be hosted on IP 1.2.3.4, create an A record like this :

flavour.mydomain.com A 1.2.3.4

If you want www.vanilla.mydomain.com to work, simply create another A record like this :

www.flavour.mydomain.com A 1.2.3.4

To set up a sub-domain, please see this post.

That pretty much ends this guide. If you have any DNS problems, post a comment below and I’ll help diagnose it.

Related posts:

1. How to set up a sub subdomain
2. How to change hosts without any downtime, step by step
3. WWW or no-WWW?