Shared printer very slow with Windows Firewall

Archived from groups: microsoft.public.windowsxp.security_admin (More info?)

It's the DCOM service... see:
http://grc.com/port_135.htm

What make/model of printer(s) are you using?
--
Cari (MS-MVP)
Printing & Imaging

<jfrensen@hotmail.com> wrote in message
news:1110317892.950398.59440@l41g2000cwc.googlegroups.com...
> My shared printer has been incredibly slow since I installed XP SP2
> and Windows Firewall. Viewing the printer properties dialog from
> a client machine takes almost a minute, and the spooling is painfully
> slow.
>
> My configuration:
> -- 3 XP SP2 computers behind a SOHO firewall router
> -- IP addresses via DHCP
> -- Windows Firewall set to enable file and print sharing on all 3
> computers
> -- One of the PCs has a local printer that it shares out to my
> local network.
>
> Printing from the PC with the local printer is fast. Printing
> from a client PC is agony.
>
> Today, I tried disabling Windows Firewall on the PC with the printer.
> This instantly fixed the printing problem -- the client PCs were almost
> as fast as the PC with the local printer.
>
> I enabled Windows Firewall again, went to the Advanced tab and turned
> on logging of dropped packets. When I tried printing from a client
> PC, I found that numerous TCP 135 packets were being received from
> the client PC and dropped. So, on the PC with the local printer,
> I used Windows Firewall to add an exception for TCP port 135, subnet
> only. Printing from the client PCs was fast again.
>
> Can someone explain why I need this port open to share a printer?
> I believe that TCP 135 is the RPC Port Mapper, and is typically closed.
>
>