Firewall/NAT

MW Experts:

We've been running MW successfully for a year, in front of our servers, and are quite pleased.  Thanks.  Yesterday, we tried to share a printer on a Windows Server behind the firewall.  Our XP and Vista machines cannot connect to it.

To troubleshoot the problem, I setup a Windows XP laptop with a LJ printer connected via LPT, and shared the printer from it.  When we put this outside the firewall (on the regular network) we can print to it fine.  We then move the laptop into the firewall and then cannot print to it.  Also, for testing, we have created a rule for my PC's IP address that allows all traffic to any destination, with logging.  We see a single Passed TCP/445 and nothing else.

Are any of you successfully printing to Windows shared printers through MW?

Thanks,

Brian

Yes, I've setup quite a few.

You'll also need make sure it's 445 TCP/UDP (both) and depending on the server setup, you might need to lower the MTU on the server to around 1400 since I've always encountered the MTU issue when using the windows print sharing over the Internet.

Of course, on a side note, having the whole world have direct access to your file/print sharing (which is often the most exploited problem with windows), I hope you are limiting who from the Internet can connect to this port?

Thanks for the suggestion.  We've read up on MTU (without much understanding), and tried a variety of things, and none have worked.  Here are some of the things we've tried:

Changing MTU on the XP test server machine's ethernet interface to 1400.  Still Failed.
Changing MTU on the MW's WAN interface to 1400.  Still Failed.
Changing MTU on the client machine's (outside of the server firewall) ethernet interface to 1400.  Still Failed.
At a command prompt, "net use LPT2: \\Server\Printer".  Works.  Then, using command prompt Copy command to copy a text file to the printer.  Works.
File sharing to the server, from an outside-firewall machine, works fine.
Printer sharing within the firewall works.

Other ideas?

Thanks much for your time and  help.

Brian

I'm sorry, I'd like to make this clearer:  File sharing have always worked, even prior to messing around with MTU.  MTU had no effect.  We are confused by this.  If file sharing works, why is printer sharing not?  Aren't they run through the same services/ports on Windows?

Thanks

Brian

We never solved this problem, but, eventually I found a work-around online.  If you add the printer using a different method than "normal", it works.

Add new printer.  Add a local printer (not networked).  Then under which port, choose Local port.  In the dialog enter the path as such: \\server\printer.  And complete the dialog.

For some bizarre, Microsoftonian reason, doing it in this method works.

Thanks for you help.

It sounds like in this case, it's not an ISP related MTU issue.

You didn't mention what version of windows server you were running, but one of the firewall options is for the port 445 to only allow the subnet to connect, you have to change it to "any" so that computer outside (from the Internet) can connect.

I guess this was already set for you, otherwise using the direct method like you did wouldn't have worked.

Either way, glad to here you found a workaround.  MS network configuring does get frustrating like this sometimes, especially once you get over into Vista land with it's many conflicting options for firewall settings, LOL.