I'm using JmDNS to discover mDNS services from a third party system. This system publishes services with names similar to this format:

TEST1._MYNET.udp.local.

They also appear to publish a PTR record for each service, to provide an alias, similar to:

_TEST1._sub._MYNET.udp.local.

The Wireshark capture decodes it as:

Answers:
    _TEST1._sub._MYNET.udp.local.: type PTR, class IN, TEST1._MYNET.udp.local.
        Name: _TEST1._sub._MYNET.udp.local.
        Type: PTR (domain name PoinTeR) (12)

etc...

I've no idea why they do this or what purpose it serves, but they're there.

Each service and this extra PTR record, have a TTL of 2 minutes.

I've seen cases where the aliased PTR record is no longer published or updated, and the related service is expired and removed approximately two minutes later. I've tried reading the source code and online resources, but I can't seem to find an answer to the following question.

If the PTR record _TEST1._sub._MYNET.udp.local. is no longer updated and expires, does JmDNS also expire the service (e.g., TEST1._MYNET.udp.local.) it is aliased to?

I hope that makes sense! Sorry if it's confusing, but I'm struggling to understand it all myself.