Service Bus namespace does not support double hyphen

Question

Following Microsoft's resource naming restriction, I tried to create a Service Bus namespace with double hyphen. However it is returned as invalid. I tried both az-cli and azure web portal.

On Azure web portal, the name "ai-stag-atlantic--bus-ejp-b" passed several validations and review but got returned as error at the deployment:

Namespace name 'ai-stag-atlantic--bus-ejp-g' is not available. Reason: InvalidName. Message: Invalid namespace name (Code: NamespaceUnavailable)

On command line:

❯ az servicebus namespace create --name ai-stag-atlantic--bus-ejp-b --location japaneast --sku Standard

(NamespaceUnavailable) Namespace name 'ai-stag-atlantic--bus-ejp-b' is not available. Reason: InvalidName. Message: Invalid namespace name

Did I read the docs wrong? Or could it be some bug in Azure's Service Bus naming validation?

Answer 1

@David Tang I had a discussion with my team internally and they confirmed that namespace names map to subdomain names. RFC5890 2.3.1 reserves the 3rd and 4th position of a name having “-“ as special-cased

consecutive hyphens are special for domain names, and the IETF having picked the double-hyphen as an “escape code” as late as 2010 (relative to the age of DNS) put up a red flag to stay away from it.

so, we explicitly blocked double hyphens specifically to avoid users being able to create “international domain names” that could be used to spoof namespace names when shown to users through tools that translate punycode.

Therefore, it is recommended to avoid using consecutive hyphens in namespace names to prevent spoofing of namespace names.

do let me know incase of further queries, I would be happy to assist you.