>>>>> "Roger" == Roger writes:

Roger> Hi, How long do gTLD servers cache dns info for?

The gTLD servers don't cache anything. They're authoritative-only. These
servers will answer with whatever's in their back-end database. If you
don't get that updated when you change the NS RRset for some .com or
..net zone, they will continue to respond with what is in that database.
Updates to the .com and .net registry database typically propagate to
the gTLD servers in 10-15 minutes.

Roger> I changed some ip's for a .net domain 2 days ago and they
Roger> still show old info.

Looks like you or your registrar forgot to tell the .net registry
(Verisign) when you did that. Talk to your registrar: the company that
registered the .net domain name on your behalf.