SFM Print Service is Limited to 127 Printers (136151)
The information in this article applies to:
- Microsoft Windows NT Server 3.51
- Microsoft Windows NT Server 4.0
This article was previously published under Q136151 SYMPTOMS
Macintosh clients cannot print to printers shared by Windows NT Services
for Macintosh (SFM) print servers. The following error message appears on
the Macintosh client:
A communication error has occurred.
The following error is logged in the event log on the Windows NT SFM
Server:
Macprint Event ID 2019 - Semaphore timeout.
Macintosh clients may also be unable to see the shared SFM printers. Also, you may receive the following event ID:
This can occur when more than 127 AppleTalk-connected printers are configured as target printers regardless if the Windows NT Appletalk printers are being accessed by Macintosh clients. When this occurs, print jobs queued to the AppleTalk printers are stalled.
CAUSE
This problem is caused by an AppleTalk Printer Access Protocol (PAP)
limitation.
In response to a connection request from a Macintosh client, Windows NT
sends the socket on which the client can respond. When there are more than
127 printers shared on a Windows SFM server, Windows NT will exhaust the
range of available sockets on the first node, and then move to the next
node (a node is a set of sockets.) But there is no provision in the
protocol to tell the client which node to use. The client continues to use
the first node, but uses the new socket. That pair corresponds to some
other printer, which drops the request and causes the errors.
This is a limitation in Apple's design of Appletalk.
WORKAROUND
A workaround exists that involves creating a service account specifically
for Print Services for Macintosh and then denying that account access to
certain printers using the Control Panel Printers tool. This will disallow
Print Services for Macintosh access to share specified printers for
Macintosh clients only.
To accomplish this, perform the following steps:
- On the Windows NT SFM server, create an account in User Manager to use
as a service account for Print Services for Macintosh. Click to clear
the "User must change password at next logon" checkbox and select the
Password never expires checkbox. Specify a desired password.
- Start the Control Panel Services tool. Click Startup for Print Services
for Macintosh. Click This account and specify the macprint account and
password information created in Step 1.
- Start the Control Panel Printers tool. Right-click on the printer(s)
that SFM should not share. Click Properties, and then click the Security
tab. Click Permissions, and then select No Access for the macprint
account.
| Modification Type: | Major | Last Reviewed: | 9/7/2001 |
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| Keywords: | kbprb kbprint KB136151 |
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