Clients Cannot Send Mail Attachments Through Modem Sharing

Small Business Server (SBS) clients running on Windows NT version 4.0 with modem sharing enabled will get poor performance when sending mail with a large attachment, or when uploading a file using FTP. E-mail can be sent through modem sharing; however, the mail client will time-out if a large attachment is send with the mail.

To resolve this problem, obtain the latest service pack for Windows NT 4.0 or Windows NT Server 4.0, Terminal Server Edition. For additional information, click the following article number to view the article in the Microsoft Knowledge Base:
Please note that this is a client-side issue and the fix will need to be applied on the SBS client running on Windows NT version 4.0.

Microsoft has confirmed this to be a problem in Small Business Server version 4.0 and 4.0a. This problem was first corrected in Windows NT 4.0 Service Pack 4.0 and Windows NT Server 4.0, Terminal Server Edition Service Pack 4.