This is one of the interesting issue which i am facing. Whenever my client tries to send a file less than 1kb, the file is transmitted successfully over ftp, but for files greater than 1kb, the files are not being transferred, instead a 0 kb file is created on the destination server.
1. Link utilization is fine
2. No crc's etc on the link.
3. server settings are perfect.
4. MTU settings default to 1500 for the WAN link.