Comment by garciasn
Could it be because folks set it low for initial propagation and then never change it back after they set it up.
Could it be because folks set it low for initial propagation and then never change it back after they set it up.
Technically the initial propagation does depend somewhat on TTL. If you query the server and get the response that the record doesn't exist, that negative response gets cached too (based on the TTL of the SOA record). But it's pretty unusual for that to matter if you're standing up a new server.
Maybe, but I don't think TTL matters for speed of initial propagation. I do set it low when I first configure a website so I don't have to wait hours to correct a mistake I might not have noticed.
That's not how TTL works. Or do you mean propagation after changing an existing RR?
It's "common" to lower a TTL in preparation for a change to an existing RR, but you need to make sure you lower it at least as long as the current TTL prior to the change. Keeping the TTL low after the change isn't beneficial unless you're planning for the possibility of reverting the change.
A low TTL on a new record will not speed propagation. Resolvers either have the new record cached or they don't. If it's cached, the TTL doesn't matter because it already has the record (propogated). If it doesn't have it cached, then it doesn't know the TTL so doesn't matter if it's 1 second or 1 month.