Ever since we connected to the internet we have run our own primary DNS
server. For the most part this has worked without issues. There is a
consultant that work for us who is dead set out outsourcing our DNS to an
ISP and just pull from them. We currently run a split DNS to hide the
private IP's and own 5 domain names.

The latest twist came when they decided to move the web hosting to this
same ISP and they demand that they control the primary DNS or else they
are unable to host us. They tell me it is because they do not assign
static IP to the web servers.

Could some of you out there offer me some advice on the pro's and con's
of letting go of our DNS server?