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5 Indispensable DNS Tools

Mon, 07 Jun 2010 14:46:21 +0000

1. Traceroute – With this quick tool, you can trace the network path from your server to any destination, including your house. If you ever have connection problems with your website or server, this tool may give you clues.

2. IP Whois – Find out what a website’s true IP address is, where it originates, who owns it, and more.

3. Reverse DNS – Test reverse DNS to make sure your server is setup correctly according to Internet protocols.

4. SPAM DB Lookup – Is your website or server on the spam list? This tool will tell you if you need to do some housecleaning or beefing up of security.

5. DNS Lookup – Make sure all of your DNS records (A, CNAME, MX, and more) are setup correctly.

There are websites that have all of these tools available either for free or for small fees. You can also perform many of them from the Linux command line, if that is available to you.

What is CNAME?

Mon, 22 Feb 2010 21:42:52 +0000

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

Mon, 15 Feb 2010 20:24:13 +0000

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

Wed, 10 Feb 2010 22:48:50 +0000

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

Using DNS Records: A, CNAME, and MX

Mon, 07 Sep 2009 14:24:43 +0000

Sometimes managing a domain involves more than simply pointing the nameserver entries to your new web host’s servers. You might also need custom DNS records. For example, if you use cloud services, such as Google’s e-mail and applications services, you will need to configure your DNS records. Three common record types you will see are A, CNAME, and MX.

An “A” record, as the name implies, is the primary record. “A” stands for address, and it is used to map hostnames to IP addresses. For example, yourdomain.com would be mapped to 55.555.555.555. That IP address is your site’s IP address, either a unique one or a shared one provided by your web hosting provider.

“CNAME” stands for canonical name. While a domain can only have one “A” record, it can have multiple “CNAME” records. Each one represents an alias. This is the one that is usually used by cloud services to map one or more of your subdomains to their services, while keeping your “A” record pointing to your host’s IP address.

“MX” stands for mail exchange record. Simply put, it identifies your mail server. Usually, you would list the IP addresses provided by your web host here, but if you are using external mail services, just follow the directions that your service gives you.

Free DNS Tools for Web Hosting

Tue, 01 Sep 2009 17:21:42 +0000

Inevitably, there are times when you need to do troubleshooting of your web and email services, or you simply need to make sure all of your network services are operating correctly. For years, I have relied on one free service to handle most of my DNS needs. It is called DNSstuff.com. They offer mail server analysis, DNS reports, SPAM database lookup, traceroute, Whois lookup, reverse DNS lookup, ping, Internet speed test, and much more.

With their full DNS report, you can enter a domain name and find out the name severs and other DNS information. It will also tell you if there are any problems with a particular domain’s DNS setup. Unfortunately, many of their services are no longer free, but there are many other services out there that still offer free advanced DNS tools.

Among the free ones are freednslookup.net, rrlookup.com, and samdns.com. If you need to know the location of an IP address, these tools will help you. If you need to know who owns a domain, you can find that out too. You can even lookup specific DNS records, such as A, MX, CNAME, and NS. Regardless of which tool you choose, it is very important to check these features before you have problems to help prevent them and whenever you have connection issues with your website.

Photo source: SXC