Windows
I can't connect to the network 1. First, make sure the problem is not a physical one. That is, check the cable connection from your network card to the hub or switch. 2. Check the LED/light at the back of your network card; the link or activity LED should be on once you've booted into your operating system, regardless if you're logged on or not. 3. Likewise, if you have access to the hub or switch, check the link LED of whichever port you're attached to, and make sure it's on. 4. If either the network card or hub LED is not on, then replace the network cable with a known good cable. Or move the cable to a known working port on the hub. 5. If you have eliminated all the physical issues, then it's time to look into the network card driver. To do so, go into Device Manager (right click on My Computer, go to Properties, select Device Manager) and look under "Network Adapters"; the model of your network card should appear here without any red "X" or yellow "!" point. 6. Once you have eliminated the network card driver problem, then it's time to check the network card protocol and configuration. 7. Right click on the Network Neighborhood icon on the desktop and select Properties, or go to Control Panel / Network. Check to see if you have the proper protocol(s) installed. Ask your network administrator to determine which protocol(s) are required for your network. I keep getting disconnected 1. First thing to check is the network cable. If possible, replace the cable or use another cable that you know is working. 2. Check with your network administrator to see if anyone else is having this problem. If you're not the only one being disconnected, then the problem may be network related, not with the system you're using. 3. If all else fails, try replacing the network card. My network performance is slow 1. Check with your network administrator to see if you're the only one having this problem. If other users are complaining about the network's performance, then the problem lies with the server and/or network itself, not with the system you're using. 2. Another system with a defective network card may slow the entire network down by resending incorrect packets. 3. If you're the only one having this problem, then try replacing the network card. Check nic and device driver 1. Go into Device Manager (right click on My Computer, go to Properties, select Device Manager) and double click on Network Adapters. Make sure your NIC model is listed here and a yellow "!" or red "X" is not listed next to the device. 2. If you see a red "X" then it means the device is disabled in the hardware profile. To enable it, double click on the NIC and clear the option "Disable in this hardware profile." 3. Also, check to see if you have any entries that read "Unsupported or Other Devices." If you do, double on the entry and see what's under the list. If you see an entry that reads "PCI Ethernet Controller" then you have to remove this entry first and restart your system. The system will detect the network card and prompt you for the driver. Check link led on nic, hub and cable. 1. Always check to make sure the problem you have is not a physical network problem. Which means checking the cable and the hub. 2. Look at the back of the NIC and you should see a couple of lights. Look for the LED that reads "link/active" or "activity"; the link LED should be on and the activity LED should flicker off and on. 3. If the NIC's link/active LED is off, then you need to check the cable and the hub, if you have access to it. The link/active LED on the hub should be on for whichever port you're using. If it isn't on, try plugging the cable to another open port on the hub. 4. If, after trying everything, the link LED on the NIC is still off, you may have a defective NIC. Network Commands ipconfig /all Display Connection Configuration ipconfig /displaydns Display DNS Cache Info Configuration ipconfig /flushdns Clear DNS Cache ipconfig /release Release All IP Address Connections ipconfig /renew Renew All IP Address Connections ipconfig /registerdns Re-Register the DNS connections ipconfig /setclassid Change/Modify DHCP Class ID ipconfig /showclassid Display DHCP Class Information control netconnections Opens Network Connections Pathping combines functions of Ping and Tracert nbtstat help troubleshoot NetBIOS name resolution problems nbtstat –a Obtains info from WINS or LMHOST (discovers who is logged on) nbtstst –A Gets info from WINS or LMHOST (discovers who is logged on) nbtstat -R Purges and reloads the remote cache name table nbtstat –n Lists local NetBIOS names. nbtstat -r Useful for detecting errors when browsing WINS or NetBIOS netstat -an | find "LISTENING" Shows open ports with LISTENING status netstat -an Shows open ports net session Shows all Windows networking sessions net use Retrieves a list of network connections net share Lists all Windows shares that are available on this machine net user Shows user account for the computer net user /domain Displays user accounts for the domain net view Displays domains in the network net user /domain Shows account details for specific user srvinfo //server Shows server info on remote share. netsetup.cpl Network Setup Wizard ping www.whatismyip.com Test Connectivity: tracert Trace IP address Route netstat Displays the TCP/IP protocol sessions route Display Local Route arp Display Resolved MAC Addresses arp –a Shows gateway MAC address. hostname Display Name of Computer Currently on Nslookup diagnose the Domain Name System (DNS) netset /display Shows a list of network components telnet Confirms whether the port is open control netconnections Launches Network Connections netsetup.cpl Launches Network Setup Wizard