Netsh commands are useful when you have any type of network issue. The following commands have fixed internet browser to domain issues.
You will need to Run the Commands in Command Line as Administrator (command prompt as administrator ) for the best results. You should reboot after the last command, instead of rebooting in-between each command.
- netsh i i r r
- netsh i i de ar
- netsh winsock reset
- netsh advfirewall reset
- ipconfig /flushdns
Reboot the system.
This should save you a chunk of time by bypassing some troubleshooting steps. If you want to dig deeper on the exact issue, continue to read below on how this works:
Note: In order, this is what you are resetting. TCP/IP, ARP, Winsock, Firewall, and last DNS. This method works well due to the order or the resets. The order is based on how packets get packed up and sent out into the world. The first three involve the packet encapsulation process and adds info to the packet headers for routing purposes. The firewall will allow the packets to go out to the world based on rules. Generally this reset helps if you can't ping out but can ping the gateway. Last is DNS and will need to be reset if the firewall is letting the packets go out but the destination host is not being resolved.
To test to see where the network issue is happening try this:
- Ping the loopback. This will test that the TCP/IP stack is working and if the drivers for the NIC are operating. Once the NIC drivers are updated and no bangs in DM run the following command in cmd. If it fails you'll reset TCP/IP.
The command is: ping 127.0.0.1
- Next ping the default gateway. This may also be the router. To find the gateway's IP, type ipconfig /all in command prompt. Then ping that number found for the default gateway. ARP deals with adding MAC address resolution address to the packet headers. Based on the Operating System ReInstall (OSRI) model this is layer 3 and MAC address and routers fall in this category. If this fails, it means that the ARP needs to be reset.
The command is: ping (IP found for their default gateway) - for example: ping 192.168.1.1
- If the above steps are successful, go ahead and try to ping out to the internet. This will test both the firewall and the DNS portions of the protocol stack. Start by pinging google.com. If it passes without errors and the customer is unable to browse online, this is a firewall issue. It would be best to reset the firewall.
If the ping test fails using the Google address, ping Google's IP address of 220.127.116.11
If the pinged Google address fails but directly pinging the IP for the site passes, it's most likely an DNS issue on the site side. If this happens you can ping Google's DNS directly at 18.104.22.168 to determine that an non-ISP DNS server can be reached.
At this point, go ahead and reset DNS, reboot, and re-try the above commands to verify that the DNS issue is resolved. If it fails again, we can determine that the protocols on the system are good to go but their ISP's DNS servers are having issues. You can manually set DNS to Google's 22.214.171.124 address.
If needed, here is a link on how to manually set the IP for DNS: https://developers.google.com/speed/public-dns/docs/using#windows