Why do domain registrars require two name servers?

Question: Why do domain registrars require two name servers?

Answer: The short answer to this question is that Internet standards require it according on RFC 1034, published by the Internet Engineering Task Force (IETF). But there is a good reason for it.

The intent of the standard is to ensure that domain name servers have redundancy. If one name server goes down, a website will still have at least one more to keep it alive. In other words, your server could be working perfectly fine, but without name servers, no one will see your site. Furthermore, sites with heavy loads might be able to distribute that load between the two name servers.

Because of the above reasons, the intent is to have two distinct name servers, at two locations, using two different IP addresses. If you have your own server and do not have access to a another server for DNS, I recommend using one of the many DNS services that are available at low cost. It will save you trouble in the long run and will make sure your site is up to standards.

Photo: Flickr

Did Rolling Stone let its domain expire?

Visitors to RollingStone.com were surprised a few days ago when instead of seeing the popular magazine’s website, they were greeted with a generic “coming soon” landing page. The website is now back up, for but some time people speculated that Rolling Stone forgot to renew its domain. What happened?

Luckily for the magazine, the domain had not expired and is actually registered through next September. The issue was most likely a DNS glitch. Regardless of the cause, Rolling Stone most likely lost a good bit of money from this slip.

Source | Mashable
Photo | Flickr

What is CNAME?

Question: What is CNAME?

Answer: A CNAME or Canonical Name record is a type of record found in DNS that allows the user to specify an alias for a domain name. For example, you can create an alias of domain1.com with domain2.com. More typically, however, it is used to create aliases for subdomains, including the most common, which is “www”.

Often a default domain record will have a wildcard (*) that will resolve any subdomain, including “www”. If it does not, it will need something like this:

www.domain1.com. CNAME domain1.com.

You can also have one point to another:

ftp.domain1.com. CNAME sftp.domain1.com.

Many mail servers will also use a mail subdomain:

mail.domain1.com. CNAME domain1.com.

CNAME records are also very useful when pointing to external domains, particularly when using cloud services like Google Apps. It effectively disguises the fact that the service is hosted on another domain.

Image Source: Wikimedia Commons

DNS Evaluation with intoDNS

Part of managing a server or even a single website is making sure the DNS is sound and in compliance with established networking and Internet standards. While you can evaluate each of your DNS entries manually, there are many services out there that make evaluation very easy.

One such service is called intoDNS, which is currently still listed as beta, but it functions very well. To use it, simply visit intodns.com and type your full domain name (excluding the “www”). Then, click “Report”. It will then scan your domain and report on a number of important issues: Domain Nameserver records, TLD parent check, CNAMEs, etc.

When your domain passes one of the tests, the service will give you a green circle with a check next to it. When there is an area of concern, you will receive a blue circle with an “i” in it. When you have an error, it will give you a red circle with an exclamation mark. All of the information is displayed in basic HTML so that you can easily print or save it.

How to setup Google Apps DNS records in cPanel

Google Apps is a cloud computing suite of services that includes web-based email, documents, and other services. Unlike standard Gmail, you can use it with your own domain (i.e. instead of yourname@gmail.com, you would have yourname@yourdomain.com). To setup your domain to use this service in cPanel, you need to edit three things:

1. MX records.
2. CNAME record
3. SPF record.

To edit the MX record, go to the Mail section in cPanel and click MX Entry. Enter the records according to Google’s specification, but exclude the period at the end, as it is not needed in cPanel.

To edit the CNAME records, click Simple DNS Zone Editor in the Domains section. If “mail.yourdomain” is already taken, you can choose another name or click Advanced DNS Zone Editor to change it.

Finally, Google recommends setting up an SPF record. This is also found in Advanced DNS Zone Editor. Once you have that setup, you are finished setting up Google for mail service, but the DNS will take some time to propagate.

Photo: Flickr

Google proposes changes to DNS system

Yesterday, Google proposed several changes it would like to see made to the DNS system. Chief among them is an adjustment to the protocol that would give authoritative DNS servers the ability to see your IP address. Currently, these name servers can only see the address of your ISP.

The change would allow websites go better tailor content to their users by knowing their approximate location. A person living in Los Angeles, for instance, might be able to visit Google News and instantly get news related to the city without ever configuring his location on the site.

To ease privacy concerns, Google has suggested that as little of the IP address be shown to the DNS server as possible. In layman’s terms, the site might see only the name of your neighborhood or town instead of your home address.

Source | ArsTechnica

CENTR releases video explaining DNS

Ever wanted to show a less-than-tech-savvy friend or family member how DNS works? CENTR, the Council of European Top Level Domain Registries, has released a new video detailing the inner-workings of the system.

In case you didn’t know, DNS stands for Domain Name System. It is essentially responsible for converting domain names into IP addresses. Even if you have a good understanding of how it works, the video is still worth checking out.

How to setup a virtual host in Apache on a Mac OS X Server

So far we have covered Linux, Windows, BSD, and Solaris. Another server operating system worth mentioning is Mac OS X Server. Although most tend to think of OS X as a desktop OS, there is a server version that has the same Unix-like structure and stability as other BSD distributions. The main difference is that it has customized visual configuration utilities.

A virtual host allows an administrator to host multiple websites on a single box. By default, Apache will only host one site. There are three steps to configuring a virtual host in Apache. They are:

1. Edit the DNS
2. Create the stie folder
3. Configure the virtual host

This is standard for Apache, but the process differs depending on the operating system. For example, on Mac OS X, the default folder for websites is /Library/WebServer, which is drastically different from the /var/www common on many Linux distributions. You can change this setting and many others to suit your preferences. For the the full how-to wiki article, see macos-x-server.com.

Source: macos-x-server.com”>macos-x-server.com

.HT domain still operational after earthquake

The 7.0-magnitude earthquake that hit Haiti earlier this week has killed 50,000 people and destroyed much of the capital. Currently, access to the nation is mainly limited to the few relief planes that can get in. Amid this tragedy there is at least some hope for Haiti, as its DNS seems to have made it through the disaster in one piece.

Here is what we know, according to ICANN:

• The administrators of the .HT ccTLD survived unharmed.
• Haiti’s IT infrastructure is heavily damaged, but the domain system is still working for most.
• Work is underway to reroute the country’s Internet traffic through the Dominican Republic.

A working telecommunications system is vital to relief crews in a natural disaster. If the domain system and other important communication links had been destroyed, thousands of additional lives would probably have been lost.

Photo | Flickr

What is DNSBL and should I care about it?

Question: What is DNSBL and should I care about it?

Answer: DNSBL stands for DNS Block List or Blacklist. Essentially, it is a published list of ipp addresses that are in some way connected to spam. Although the most common form of DNSBL is a list of actually servers and/or computers that actually send spam, there are some that flag ip addresses based on association with spamming computers or the potential to send spam. The latter two are particularly controversial.

The reason you should care about DNSBL is that there is always the possibility that your server could end up on one. If you run a dedicated server with multiple users, the potential is greater because you could actually have users who abuse their privileges and send spam. As a result, their ip address will be flagged, and if that ip address is shared with others, everyone suffers.

The result is that any other email servers that rely on the lists will reject email sent from your server. You can prevent this by ensuring that your server is locked down and not an open relay for spam. Furthermore, you can periodically check the most common block lists to see if your ip addresses are listed. If they are, find out how spam is being sent through your server and eliminate the problem. Within 48 hours of fixing the problem, most lists will remove your IP addresses.

Photo: Flickr