The "11 port" thing is about the ports used by the client to establish a
connection with an LPD on a server. RFC 1179 says that the client (lpr)
must use ports 721 through 731 to send to the lpd port (515).
There is no limitation on what sending ports the LPD function in Print
Services for Unix will respond to - the LPD listening on port 515 will
accept connections from any source port.
In older versions of Windows (NT 3.51 prior to Servcie Pack 5), the LPR
client would only send print on ports 721-731. So, if there were more than
11 printers defined on a computer to use LPR, there could be printing
slowdowns etc.
Registry entries were added to NT 3.51 and NT 4.0 by Service Packs that
allow LPR to use (send on) ports other than those defined by RFC 1179. The
"Standard TCP/IP Port) in Windows 2000 and later has this turned on by
default - it will always use any available port above 1024.
If you choose to use the LPR Port created by Print Services for Unix
(instead of the "Standard TCP/IP Port), it will restrict source ports to
conform to RFC 1179 by default (721-731). KB article 179156 discusses this
and how to configure the Print Services for Unix port to use any available
port.
See
http://support.microsoft.com/default.aspx?scid=kb;en-us;141708
http://support.microsoft.com/default.aspx?scid=kb;en-us;179156