I'm having a real head-scratching moment here.
I'm in the process of migrating from Ex2007 to 2010 SP3 for a customer. All is well, and almost all users are over. So I turn my attention to Public folders. They're replicated from old 2007 cluster to one on each DAG node (two).
They're also set to a static RPC port, which is open in the firewall.
But Outlook clients (I suspect not all, but most) keep getting ye olde 'Exchange network connectivity' errors; and I see in the RPC dialog that Outlook is hammering the server, and keep blinking between connecting and established for public folders. After some stuttering, they MAY see the public folder tree, but I see it's fired up a connection to the old 2007 base, so that's probably where that comes from.
If I switch default public folder database to the old 2007 base, it seems to work fine.
Anyone got any ideas? I have no idea what's going on; I see it's connecting using the correct port; and if I switch (I have two RPC ports open), they do the same on the other port.