LAST_ACK

I am working a mixed environment of Windows servers, Unix servers, and linux servers. We have Windows, Citrix and linux clients. We have recently introduced Mac clients running Leopard to our network. These clients need to access Windows file shares, and are able to through the Finder by clicking on the Windows server as listed and entering the proper credentials. The problem I am having is that the Mac clients are leaving the Windows server with many active connections in the LAST_ACK state. I have included a portion of the netstat output below for both the Mac client and the Windows server. The connections on the Mac client do eventually time out as expected, however the Windows does not seem to receive a final acknowledgement from the Mac client. As a result, Netbios on the Windows server cannot service anymore requests and dies when a certain maximum is reached. We have not experienced anything like this for any of the other platforms we use. Any ideas or suggestions would be appreciated.

Thanks,

Jim

From the netstat output on the Leopard client:

…
tcp4 0 0 172.18.32.24.54086 172.18.10.31.139 FIN_WAIT_2
tcp4 0 0 172.18.32.24.54018 172.18.10.31.139 FIN_WAIT_2
tcp4 0 0 172.18.32.24.54019 172.18.10.31.139 FIN_WAIT_2
tcp4 0 0 172.18.32.24.54008 172.18.10.31.139 FIN_WAIT_2
…

From the netstat output on the Windows NT 4.0 server:

Active Connections

Proto Local Address Foreign Address State
…
TCP 172.18.10.31:139 172.18.32.24:62300 LAST_ACK
TCP 172.18.10.31:139 172.18.32.24:62301 LAST_ACK
TCP 172.18.10.31:139 172.18.32.24:62325 LAST_ACK
TCP 172.18.10.31:139 172.18.32.24:62334 LAST_ACK
TCP 172.18.10.31:139 172.18.32.24:62359 LAST_ACK
TCP 172.18.10.31:139 172.18.32.24:62374 LAST_ACK
TCP 172.18.10.31:139 172.18.32.24:62375 LAST_ACK
TCP 172.18.10.31:139 172.18.32.24:62380 LAST_ACK
TCP 172.18.10.31:139 172.18.32.24:62404 LAST_ACK
TCP 172.18.10.31:139 172.18.32.24:62410 LAST_ACK
…