It seems this user can’t connect to the mysql gets access denied:
Access denied for user ‘user’@'machine_bbbbb’ (using password: YES)

Note that the machine the user is being seen from is totally different from the one I set up in the grant!! WHY?

run a reverse lookup on the ip of machine_aaaaa, turns out it shows machine_bbbbb. So I figure a big bad guy messed up /etc/hosts, I was right! `cat /etc/hosts` just to find an entry for machine_aaaaa blehh

Ok, solution is to remove the entry from /etc/hosts (after finding out it wasn’t even necessary and wasn’t even supposed to be there in the first place), restart nscd.

Retry
AGAIN – Access denied for user ‘user’@'machine_bbbbb’ (using password: YES)

What the ….

What’s wrong now? — yeah silly me forgot to `flush hosts` :)

Retry
YOHOO I’m in!

I’ve seen quite a few blogs about disabling name resolve in mysql with skip-name-resolve and granting privileges using IPs – something which would also have avoided the above (but still not found the root of the problem):

http://jeremy.zawodny.com/blog/archives/011421.html
http://www.mysqlperformanceblog.com/2008/05/31/dns-achilles-heel-mysql-installation/