I have a rails app that is (was) working with MySQL 5.0. Until yesterday that is when I started mucking with the MySQL GRANTs. Right now I have grants for the following: User Host root % root 192.168.0.63 root localhost The rails server is 192.168.0.63. In database.yml I have used socket: as well as host: and I am getting login errors despite having what I think are valid grants that map to localhost, the ip, and a socket login. In fact I can log in using the mysql command line client with no problem. Now, when I was mucking with grants, I noticed one thing. There was one root grant that used the newer mysql 41 byte PASSWORD() hash. All the other grants use the older 16 byte hash. I thought the grant with the longer hash was redundant and stale so I removed it. Would rails require a grant with the newer larger hash? It seems to me that one of the combinations of grants and hosts in database.yml should have worked. Gary