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DNS-SD Configuration “Gotcha”

weLostâ„¢ uses DNS-SD, DNS Service Discovery, to bootstrap the location of its social network servers. While this was a good idea, it had a very subtle “gotcha” in its configuration. The basic configuration instructions are described here in: Static Server Setup. If you do not intend to support browsing for your resources, then things are even simpler but there is still that pesky “gotcha”. To support direct access you only need to implement the third set of DNS records. The one’s labeled: “SRV & TXT records describing each service entity named above”.

If my experience with the iPhone is a guide, the TXT record is not optional. Every service you query MUST have a TXT record. In my case, I neglected to set the TXT record for my narrow web HTTP server. This caused every NSNetService query to timeout. Solving this problem was simple, I entered “txtvers=1” as the body (minus the quote marks) for the TXT record. This is a default version of the format of all DNS-SD TXT records. There are other values you could use, particularly for HTTP, but this one is both innocuous and sufficient.

Enjoy and Anon,