Issues with Network (by 2 users)

In order to get to the Internet, a computer must have proper IP connectivity. Lets start by troubleshooting IP connectivity in your office and see where the breakdown is.

Open a command prompt on a machine. This can be done by going to Start -> run and typing the following:

cmd:

Then hit OK. A small window should open up with black background and white text.

In this window, type the following command:

ipconfig /all

Hit return. You should have output like this:

Ethernet adapter Local Area Connection:

Connection-specific DNS Suffix . :
Description . . . . . . . . . . . : Broadcom 570x Gigabit Integrated Controller
Physical Address. . . . . . . . . : 00-0B-DB-99-81-00
Dhcp Enabled. . . . . . . . . . . : Yes
Autoconfiguration Enabled . . . . : Yes
IP Address. . . . . . . . . . . . : 10.10.30.27
Subnet Mask . . . . . . . . . . . : 255.255.254.0
Default Gateway . . . . . . . . . : 10.10.30.1
DHCP Server . . . . . . . . . . . : 192.168.1.52
DNS Servers . . . . . . . . . . . : 10.10.30.10
192.168.1.24
Primary WINS Server . . . . . . . : 10.10.30.10
Secondary WINS Server . . . . . . : 192.168.1.24
Lease Obtained. . . . . . . . . . : Friday, October 06, 2006 1:46:55 AM
Lease Expires . . . . . . . . . . : Saturday, October 07, 2006 1:46:55 AM

Take note of the value for Default Gateway. Trying pinging this IP address with the following commmand:

ping 10.10.30.1

You should get a response like this:


Pinging 10.10.30.1 with 32 bytes of data:

Reply from 10.10.30.1: bytes=32 time<1ms TTL=255
Reply from 10.10.30.1: bytes=32 time=1ms TTL=255
Reply from 10.10.30.1: bytes=32 time<1ms TTL=255
Reply from 10.10.30.1: bytes=32 time<1ms TTL=255

Ping statistics for 10.10.30.1:
Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
Minimum = 0ms, Maximum = 1ms, Average = 0ms


Look at the % loss item. If this is zero, that is good. If it is 25%, try running the command again and see if it comes up as 0 the 2nd time (some times this happens and is normal).

If you continually get non-zero values, then there is a problem with your default gateway.

Run the same commands on another computer. Try pinging the IP address of the first computer from the second computer. If you cannot do this, then there is a problem with the switch.

Another thing to note is that if the IP address values come up as 169.254.x.x, and there is no default gateway, then there is a problem with your DHCP server.

Also, check to make sure there are values listed for DNS servers. If there are no values for DNS servers, then you will not be able to get out to the Internet.

Unfortunately, there are many different things that could be wrong with your environment. Hopefully this will give you some ideas as to where to start trouble shooting.