We have a simple office network with the following structure: DSL Modem -> Checkpoint 620 -> TP-LINK TL-SG1016 -> Ethernet ports around the office -> Computers & Printers. The CP620 also have Wi-Fi on with a password for some mobile devices.
All of the devices are getting their ip`s & DNS from the CP620, based on their MAC Address.
All computers are running Windows 8.1 + Bitdefender GravityZone endpoints with the same policy.
All devices are working perfectly.
There is one computer which loses it`s internet connection (but not the local network connection) every few hours, for 10-20 minutes. It has the exact same hardware like the rest of the computers. It has the Same updates and drivers installed. A restart sometimes help.
I have tried:
- Changing DNS addresses to OpenDNS, GoogleDNS and manually inputting the ISP
s DNS in the computer
s network settings. - Skipping the patch panel, old cables and old Ethernet port, and connecting the Computer directly to the Switch.
- Reinstalling Windows.
- Resetting BIOS
- Comparing The computer`s settings to the other computers.
- Resetting and re-configuring the router and modem.
- Installing different NIC driver`s (older version).
- Disabling VirtualBox virtual network interface.
- Trying linux, which as far as I remember, showed the same behavior.
- Installing a PCI-E NIC, and using it instead of the built-in motherboard NIC.
None of these helped.
The network is very simple. No special polices, proxys, everything that is blocked or allowed on one computer, is blocked and allowed on the rest of the computers. The strange part is that that previous computer that was in this physical area, showed the same behavior. It had totally different hardware, ran Windows XP, and was connected to an older switch at that time.
While I am not system admin, I am the guy currently taking care of the computers and network, and I find this specific issue a very strange one. I would appreciate your help, and will provide any log/info/tests results necessary.
Thank you very much, Noam.