Home Network, strange behaviour since Comodo Firewall

Having dumped Zonealarm and come over to Comodo Firewall, I am very impressed in general. However, there is a strange behaviour that I can’t resolve.

I have a home network (workgroup) consisting of PC1 (Windows 7) and PC2, PC3, PC4 (all XP).

Windows Explorer in PC1 lists under Network all the XP machines. However, files can only be accessed on PC2 and PC3. When clicking PC4 I get the error “PC4 is not accesible. You might not have permission to use this network resource. Contact administrator… Logon failure; the user has not been granted the requested logon type at this computer”.

I can ping fine both ways between PC1 and PC4.

The only thing I can think of is that I changed the IP address on PC4, after having installed Comodo. But I updated that in “Network Zones” and ran the Stealth Ports wizard to define a new trusted network.

Everything else appears identical for PC2,PC3,PC4 and these haven’t changed since the Comodo install on PC1.

Incidentally, there is another XP machine PC5 which I didn’t add to the Trusted Network, but I can still access it.

Does anyone have any ideas?


This error message is well known under windows, unfortunately, there’s no single solution. Usually it comes down to something simple but it’s important to work through the options. Hence:

  1. Is the workgroup name the same on all PCs
  2. Are you connecting using a defined user account that’s the same on all PCs
  3. Has a ‘Homegroup’ been defined on the Windows 7 PC
  4. Try using a UNC path to connect as opposed to browsing.

Thanks for the suggestions. I can confirm that, as part of establishing the network, I’ve done a number of things, including those listed below:

  • Workgroup is the same on all PCs
  • Each PC is using the admin account, with the same password
  • No Homegroup on Windows 7, only Workgroup
  • Method of testing, I am entering “\192.168.0.x” direct into Explorer
  • Static IPs
  • Folder shared on both machine, with full security access granted
  • Reboted machines and router several times

Is there antything else to check ?

Just out of interest, is CIS running on all PCs, if so, what happens if it’s temporally disabled? Other than that:

  1. Add the ‘everyone’ special group to the ACL on the share.
  2. Disable password protected sharing under Advanced Sharing Settings on the Windows 7 PC, also make sure Network Discovery is enabled.
  3. Check the connection with the encryption to 56 or even 40bit. Also under Advanced Sharing.