Today I tried printing on a shared printer on one of our homegroup members. Sadly it did not work (printer marked as offline). Shortly after, I noticed I can't even ping the machine that owns the printer (I also can not remotely access it in any other way I've tried).
Currently I'm trying to ping the machine from the router both computers are connected to (and my machine in question doesn't answer). I do receive the echo requests (as verified with WireShark). I also added a rule in the Windows Firewall to specifically allow ICMP echo requests, but that didn't change anything. I also tried netsh firewall set icmpsetting 8 enable, but that didn't change anything either. Completely disabling the Windows Firewall has no effect on the issue either.
One has to wonder, where does Windows log when and why it ignored any incoming packets? How can I get to the bottom of this?
Here are some ways I found to dig deeper into the issue:
Enabling logging on the Windows Firewall
Enabling Windows Filtering Platform Auditing
Both methods at least give more insight into the issue. The plain log file is full of entries like this:
2011-11-11 14:35:27 DROP ICMP 192.168.133.1 192.168.133.128 - - 84 - - - - 8 0 - RECEIVE
So the ICMP packets are being dropped as if that was intended.
The Event Viewer now gives a little bit more details:
The Windows Filtering Platform has blocked a packet.
Application Information:
Process ID: 4
Application Name: System
Network Information:
Direction: Inbound
Source Address: 192.168.133.1
Source Port: 0
Destination Address: 192.168.133.128
Destination Port: 8
Protocol: 1
Filter Information:
Filter Run-Time ID: 214517
Layer Name: Receive/Accept
Layer Run-Time ID: 44
This same entry is always repeated with 2 points of information changing:
Process ID: 420
Application Name: \device\harddiskvolume2\windows\system32\svchost.exe
The service host with the PID 420 is the host for the following services:
Windows Audio
DHCP Client
Windows Event Log
HomeGroup Provider
TCP/IP NetBIOS Helper
Security Center
Additionally, there is currently this problem with the same machine:
Even though my network is set to be a "Home network", I am unable to create a new homegroup.