Here is a good paper on what ICE is, and what it does.
Basically ICE is a inter process communication protocol, with authentication, protocol negotiation and potentially multiplexing built in.
It allows two X clients to talk directly to each other, for example, a video player program could potentially talk to a jukebox program to update each other.
As Richard Holloway says, the .ICEAuthority file is for authentication. It contains a number of random cookies. If two programs have the same cookie, then they're allowed to talk to each other. In practice this either means that they're reading the same .ICEAuthority file, or the cookies have been added.
In a lot of ways it's similar to the xauth program & the .Xauthority file, except that .ICEAuthority is used for client to client, while .Xauthority is for client to server.
This gives a list of files which are deleted, but still referenced by processes.
FYI, internally, the system already replaced the filename, hence it points to the new data.
The old data blocks still exist at the disk until the remaining applications have closed the file.
I assume your server is/was configured to authenticate against LDAP at some point.
My suspicion is you have a PAM module that relied on a specific version of the OpenLDAP libraries, and those libraries have been either removed or changed (upgraded/downgraded).
Find out what changed and reverse it. Alternatively as a quick fix you can scour your /etc/pam.d directory for stuff that authenticates against LDAP and temporarily comment them out (assuming that it won't destroy your universe to do so).
Best Answer
Here is a good paper on what ICE is, and what it does.
Basically ICE is a inter process communication protocol, with authentication, protocol negotiation and potentially multiplexing built in.
It allows two X clients to talk directly to each other, for example, a video player program could potentially talk to a jukebox program to update each other.
As Richard Holloway says, the .ICEAuthority file is for authentication. It contains a number of random cookies. If two programs have the same cookie, then they're allowed to talk to each other. In practice this either means that they're reading the same .ICEAuthority file, or the cookies have been added.
In a lot of ways it's similar to the xauth program & the .Xauthority file, except that .ICEAuthority is used for client to client, while .Xauthority is for client to server.