[computertechie]

I have 3 computers in a workgroup, all have same workgroup name. Computer 1 can ping anything (internal or external), while computers 2 and 3 can ping anything except for computer 1. They are all Windows XP and using DHCP.

I have:
- Run the repair option on the network adapters at least twice.
- Given them all a static IP
- Tried a hosts file
- Enabled NetBIOS over TCP/IP
- Made sure firewall is disabled on all 3
- Removed network adapter in Device Manager and re-detected.
- Tried another network cable for computer 1
- Rebooted the router

If I try to ping computer 1, it won't ping, but the entry for computer 1 will appear in the arp cache afterwards.

It was working until recently and then just stopped working for no reason. Computer 2 uses the printer on computer 1, and obviously now can't.

What is the reason for not being able to ping computer 1?

[an_innocent_raj]

You must be using some kind of security. Some kind of firewall or antivirus on that computer that is blocking
So disable all the firewalls and antivirus that will resolve your problem

[computertechie]

The firewalls are disabled on all 3 computers. No changes have been made to the system, it just stopped working.

[JohnWill]

Failure to ping is almost always a firewall issue. Some software on Computer 1 is blocking the ICMP request.

[computertechie]

Yep, it was a firewall alright. I never noticed Norton Internet Security was on the computer (just thought it was Norton AV).

I disabled the Norton firewall on the computer (they've got a firewall on their router), but still have no idea why it stopped working in the first place as no-one made any changes.

[JohnWill]

It's one of the mysteries of Norton.

You can mark your own threads solved using the thread tools at the top of the page in the upper right corner.©

[computertechie]

I still wonder why people use Norton AV or Norton IS. But that's for another thread.

Thanks chaps.