[chuckhole]

I would like to start this thread by adding a few steps to take for basic network troubleshooting:

Q) How do I go to a command prompt?
A) Click on Start, Run and type CMD and then OK.

Q) How do I see my IP configuration (network information)?
A) Go to a command prompt and type IPCONFIG /ALL and hit ENTER.

Q) How do I save my IP configuration to a file and view it?
A) Go to a command prompt and type IPCONFIG /ALL > C:\RESULTS.TXT and hit ENTER. Then open Notepad and open the C:\RESULTS.TXT file.

Hint: After opening your IP configuration results file, you can copy the information to a posted question on the forum.

Q) How do I refresh or repair my IP address?
A) Go to a command prompt and type IPCONFIG /RENEW and hit ENTER. If it was successful, you will be shown the IP address of your connection.

Q) Are there other things that I can do with the IPCONFIG utility?
A) Yes, to see a list of the options, type IPCONFIG /? And hit ENTER. For example, if you want to see the information in your DNS cache, type IPCONFIG /DISPLAYDNS and hit ENTER.

Q) How do I know if my computer is communicating with other computers?
A) There are a few ways to do this. One is the PING utility. If you know the name or IP address of the other comuter, then go to a command prompt and type PING IP_Address and hit ENTER. Example: PING 192.168.1.1 or PING YAHOO.COM. You should get four successful replies.

Hint: to see other PING options, type PING /? and hit ENTER.

Q) How do I know if my computer is communicating with other computers if I do not know the name or IP address of the other computers or hosts?
A) Your computer may be communicating with other machines without your knowledge. To see exactly what your computer is doing, go to a command prompt and type NETSTAT -O and hit ENTER. A list of the computers and IP ports that your computer is in contact with will be given to you.

Hint: to see all the ports that your computer is listening on, type NETSTAT -A and hit ENTER. To see all of the NETSTAT options, type NETSTAT /?.

Q) What is an IP Port?
A) TCP/IP is actually a suite of utilities. In the same way that many different types of mail can be delivered to your house, there are many different types of communication that exist on the Internet and we get junk mail there too. In the same way that you would use a box, a plain envelope or a windowed envelope for different types of mail, a port is used for different types of communication. The most common ones used on the Internet are for browsing (HTTP - 80), file transfer (FTP - 21), sending email (SMTP - 25), and receiving email (POP3 - 110).

Hint: to see a complete list of the well known ports, go to http://www.iana.org/assignments/port-numbers.

[retsoksirhc]

Great info here! I'd like to add a few troubleshooting tips, the build on the explanations given:

Q) So these ports getting 'junk mail', how do I stop that?
A) That's where the Firewall comes in. Firewalls set up rules that basically say you only want to allow mail that has my address on it. And only through these ports. Everything else just basically hits a brick wall.

Q) I can ping websites, but they don't show up when I try to go to them! What's the deal?
A) You need to check your Proxy settings. This is especially an issue if you use a laptop at your company; it may be set for the company's proxy server. For Internet Explorer, go to Tools -> Internet Options -> Connections tab -> LAN settings. Generally, ONLY checking the box for Automatically Detect Settings will work. If you know there isn't a proxy, you can uncheck everything.

Q) My wireless says Limited or No Connectivity. How do I fix it?
A) Usually this is security settings. Make sure you know the security key for the network. Open up control panel and go to network connections. Right click the wireless network connection, and click Properties. Click on the Wireless networks tab. If you use a program instead of windows to manage wireless, open the program instead (your steps will differ... you need to find the list of networks that you connect to). Click on the network you're trying to connect to, and click properties. Re-enter your wireless security key, and save. Click OK. Right click the Wireless Network Connection again, disable it. The right click and enable it. If it still doesn't work, go into the Wireless networks tab again, click the network, and click Remove. Click View Wireless Networks. (You may have to click Refresh on the left.) Click on the name of your network and click Connect. This will put all the settings in for your network, starting from the ground up. All you should need is the security key.