dns traversal paths

fyi: managed dns services - edgedirector.com

The complete process used by a dns client such as a dns cache to obtain the answer to a query is called dns traversal. The dns resolving process starts at the root servers. Upon receiving a valid query, the root servers will answer the query in the form of a referral to the appropriate parent servers for the tld.

The parent servers will return an answer in the form of a referral to the nameservers of the domain in question. If the authoritative name server is in a domain which is also served by the parent server, and the requisite glue records are available, then the ip addresses of the name servers will also be returned in the answer.

In all other cases, the referral will not contain the ip address information. The dns cache must restart the query to obtain the name server addresses from the root level. An exception exists where the name server is already known to the client. This is one of the advantages of using a busy well known server. The name server data is likely to be known to the cache even for unpopular queries.

As can be seen, .com and .net domains have an advantage in terms of name resolution complexity. The disadvantage that other tld domains face in the traversal process can be somewhat mitigated by careful choice of name servers. One of the mitigating factors is the choice of a well known name server that is likely to be already known by a dns cache from previous lookups for other clients.

Although it is not possible to eliminate this disadvantage, edgedirector.com has structured it's name server zone placements to avoid this problem as much as possible.

Our advice is to consult with the experts when choosing the placement of your name servers in the dns hierarchy. Not all names are created equal. We would be pleased to advise you on the correct choice for your chosen domain name.