Common Network Troubleshooting Methods

There are DOS prompt commands helping you to conduct the TCP/IP network troubleshoot: ping, tracert, nslookup, route, telnet.

Ping is used to test point to point connection. If ping an IP is successful, it means the TCP/IP network between them is OK, but not sure abut DNS; if ping an DNS name is successful, that means DNS is OK too.

If ping an IP is not OK (time out, or unreachable), we can use tracert to know which routing segment of the whole path has problem.

If ping an DNS name is not OK, then we can use nslookup to test if your DNS is in good condition. You can either host DNS yourself, or ask your ISP to host your DNS.

There is a web site called http://www.dnsstuff.com. This site has lots of tools to help you to make sure you DNS and SMTP e-mail server are correct.

If you can ping the other site by DNS name, but still can not access that site via HTTP or FTP or SMTP or POP3, then you can use telnet thatsite portnumber to diagnose the problem. For example, telnet bnet.thesite.com 80 will be able to communicate that site using HTTP. You will need to be familiar with HTTP to continue the test. For example, the first command after this line can be:

get /

to get then home page displayed.