What do I need to know about DNS and Convio?

This document will attempt to explain the basics of DNS and how it is used for clients’ sites at Convio. DNS stands for the “Domain Name System” and is used, at a high level, on the Internet to convert easily readable names (i.e. domains) to machine readable IP addresses. Many describe DNS using the phone book analogy wherein you look someone up by name (easy to remember) and determine a number (harder to remember); DNS is, in fact, much more complicated than this but the analogy works at a high-level. You can think of DNS as a 3-part system consisting of a Domain Registrar, which points to a DNS Hosting Provider, which points to a Web Site (or email) Provider who then serves the site (or email). I’ve outlined the DNS process below followed by a diagram, which further illustrates how DNS works.

The DNS process starts with a Domain Registrar (e.g. Register.com or Network Solutions). Once a client decides on a domain to use (i.e. <some name>.<extension>), they must purchase and publicly register it with a Registrar. It is here that they specify the administrative and technical contacts for this domain (i.e. the definitive owner). If a domain is already registered to someone else the client must select something different (or, rarely, buy the domain from the current holder). Often a good choice is to simply use another extension; so if foo.org is taken then try foo.net or foo.info. The list of acceptable extensions includes: .com, .org, .net, .us, .biz, .info, .tv, .ws, and .cc. There are also a slew of country extensions including .us, .uk, .au, etc., etc.. It is also a decent idea to purchase the name of your domain with multiple extensions.  When a client registers a domain, they must specify nameservers (usually 2 or more) to which the domain will be pointed. These nameservers are computers that belong to a DNS Hosting Provider, the entity who holds the DNS records specifying to where a domain or subdomain resolves. Some examples include Register.com, Network Solutions, UltraDNS, UUNet, Verio, your web hosting company, or your local ISP. In any case, the client must have this type of service from some provider; a frequent question is if Convio provides this and the answer is No.  It is with the DNS Hosting Provider that the DNS records (or zone file) for the domain reside and thus where our clients need to make the necessary changes. These records specify where domains and subdomains will be directed. The various record types that we may be concerned with are:

• A = References an IP address to resolve to.

• CNAME = canonical name; this is just an alias to re-direct to; this is more flexible as we can change where the alias goes to; an IP is a very hard coded value.

• MX = mail exchange (usually the IP or alias of the mail server).

• NS = name server entries

You can view the various records for a given domain by going to http://www.dnsstuff.com/, entering the domain in the Lookup box in the top right corner, and selecting the record type you’re interested in. For all Convio clients they will either have 2 A records pointing to the IPs of our web servers (66.45.103.69, 66.45.103.5) and/or a CNAME entry that references “<short_name>-live.convio.net”. This is not a domain that’s accessible with a browser, but rather an alias used internally by our webservers to serve the appropriate site. All clients are required contractually by the Service Level Agreement to use a CNAME record to help us ensure minimal downtime in the unlikely event of a catastrophic failure. For clients using their root domain for their Convio site (e.g. jnf.org) we use both 2 A for the base domain and 1 CNAME record for the “www” entry. For clients just using a subdomain (e.g. tour.diabetes.org) we require them to use a CNAME.

You can see that you can literally create infinite subdomains using DNS. Once you own the root domain, you own any and all subdomains associated with it. So if a client tells you they have “foo.org” and they want their Convio site to be “support.foo.org” they do NOT need to register a new domain. They simply need to add an additional CNAME record to their existing configuration with their existing DNS provider.

Warning: For those familiar with DNS it is not simply a matter of pointing your domain name to the IP address of Convio’s servers. Doing so without coordination with Convio will result in a “Site not Found” error. This may differ from your past experience with single site web servers. Single site web servers do not pay attention to the site name in the URL, whereas ours do.

Useful Links:

Sites for more additional information:

http://www.dashsystems.com/surprise/surprise_dns.cfm

http://www.atlasindia.com/dns.htm

http://www.menandmice.com/online_docs_and_faq/glossary/glossarytoc.htm

To see DNS settings (lookup), do a WHOIS, and a load of other stuff you’re not likely interested in:

http://www.dnsstuff.com/

List of Registrar Codes to Registrar Names (for use with esoteric WHOIS results):

http://www.pir.org/whois_search/registrar_whois_ids

To do a reverse lookup (see who an IP belongs to):

http://arin.net