Users are being in turn directed to old server, then new server and back to old!

Hi. I moved my 16 domains to a new dedicated box. I was having very high expectations on moving to a brand new dedicated quad core with 32GB RAM, 2x 3TB disks and a hardware RAID1 controller.

I wanted at the same time to change nameservers. I went to my registrar and changed the IP addresses of two nameservers I created a year ago. The nameservers were there, I just changed their IP addresses to match my new server (1 shared + 1 dedicated IPs).

I went then to my dedicated box, went to plesk admin, picked the right domain and added two A records with the IP addresses of the server.

I placed a big red notice on my old site saying: sorry, you are on our old server and hence the forums are closed.

It took about 24 hours, then an ipconfig /flushDNS was enough to get rid of my cache and on pinging my domain I was pinging the NEW IP address. I was happy. Everything was as expected.
On my new server, I put on my forums a big green notice saying: hey! you are on our new server!

A few hours later, I received a few mails from a few members of my forums telling me that after having been on the new server for a few hours now they are back on the old server

I checked, and right, for some reason, on pinging my site I was pinging the old server IP.

I waited a few hours and I was again pinging the new server. I thought OK for some reason, the change was not stable on whatever name resolver I am behind but no big deal.

The real horror film started when tens of users started mailing me telling me that they are moving alternatively between the old and the new server. I thought nightmare should not be long before everything is stable on all sides. But this has been ongoing now for 2 days and counting!

Anybody has any idea what horror tunnel I am in?

Any suggestions to see some light?

Is this problem with all 16 domains, or just 1 in particular you are trying out first?

If for all domains, did you go and change the Nameservers at the registrar for all domains?

If you can list a domain or two, I can see what I find. (Or you can PM it if you feel more comfortable that way).

Make sure your NS records are also the new servers. If the glue records are correct but the NS records point to the old server, that can potentially cause exactly what you are describing about intermittent problems.

thank you very much.