OS user defined in LDAP and sftp performance.


Environment :

OS : AIX 5.3
OpenSSH : 4.3p2

When logging in using ssh with a user defined in LDAP, the 'ls -l' of any given directory is done within seconds.
When giving the 'ls -l' command via a sftp session, this can take upto minutes (depending on the amount of entries in the directory).
This is not an issue with the sftp client, as I've tested several sftp clients (OpenSSH, F-Secure and WinSCP) and all have the same problem.
It seems that the issue has to do with the combination of the user being defined in LDAP and sftp.
To be clear, this even happens when the owners of the files/directories that are being displayed with the 'ls -l' command are local users.

Did anyone come across this issue or anything like it?
Thanks in advance for any insight given in this matter.

Kind regards,
Mark van Huijstee