Poor CIFS performance between linux box and NetApp NAS

Issue

• Slow transfer speeds between linux box and NetApp NAS.
• The network team says the network looks good.
• Packet trace showed several things are happening, but the most worrisome looks like these STATUS_INTERNAL_ERROR messages from the NetApp.
• Both client and server seem to have no trouble talking with other users or servers at other sites, though NetApp NAS has had some complaints from end users.