Windows Tip Sheet
Talking to the Wall
Windows Firewall can sometimes do too good of a job in blocking Internet traffic.
This tip is part 5 in a series of 5 on living with Windows XP Service Pack
2.
I get a lot of Windows Management Instrumentation (WMI)-related questions on
my Web site, www.ScriptingAnswers.com.
One of the biggest ones that’s been coming up lately is folks getting
“RPC Server Not Available” messages when trying to connect to remote
machines via WMI. Normally, that might be a topic for my Scripting
Answers column, but this is so prevalent that I figure everyone deserves
to know the answer. Besides, it affects far more than just WMI or scripting
-- it actually affects most remote administration of WinXP machines running
XP2.
The problem, of course, is the tricky little Windows Firewall, which is blocking
incoming connections to both the WMI service and a host of other useful services.
There are a number of ways to fix it: Group Policy would be my first choice,
since it provides a nice, centralized means of managing Firewall exceptions
(which is what you have to create), and since that’s basically the whole
point of Group Policy in the first place.
You could also write a script that does this for you, and maybe deploy it in
a login script (as opposed to trying to connect remotely, which obviously won’t
work because the Firewall is on). I’ve included some links below that
offer a few means of correcting the problem.
One cool option would have been to fix this in your SP2 deployment. I know,
too late, right? Well, there’s a link for doing that, too, if it’s
an option for you and you haven’t rolled out SP2 yet. And, by the way,
get on it! SP2 is a great addition to your network, hiccups like this notwithstanding.
More Resources:
- Read this nice, long Knowledge
Base article on the subject.
- More than you ever wanted to know on connecting to WMI through the Firewall,
plus configuration instructions, here.
- Write a script
that modifies the Firewall (assign it as a logon script, maybe?).
- Scripting
the SP2 deployment to correct the Firewall in the first place.
About the Author
Don Jones is a multiple-year recipient of Microsoft’s MVP Award, and is Curriculum Director for IT Pro Content for video training company Pluralsight. Don is also a co-founder and President of PowerShell.org, a community dedicated to Microsoft’s Windows PowerShell technology. Don has more than two decades of experience in the IT industry, and specializes in the Microsoft business technology platform. He’s the author of more than 50 technology books, an accomplished IT journalist, and a sought-after speaker and instructor at conferences worldwide. Reach Don on Twitter at @concentratedDon, or on Facebook at Facebook.com/ConcentratedDon.