The Internet Architecture Board has released a commentary entitled Architectural Concerns on the use of DNS Wildcards.
The commentary gives both an explanation of some fundamental design issues that are created by the use of DNS wildcards, and an account of problems encountered in a recent experiment with wildcards.
Besides recommending strongly against the use of wildcards in TLDs (and most other situations), the IAB suggests a simple, but powerful guideline: If you want to use wildcards in your zone and understand the risks, go ahead, but only do so with the informed consent of the entities that are delegate within your zone.
The document concludes with the recommendation that any and all TLDs which use wildcards in a manner inconsistent with this guideline remove such wildcards at the earliest opportunity.
