Troubleshooting Configuration Problems; Determining Your Ip Address - SMC Networks D3CM1604 Administrator's Manual

In addition, some operating systems, such as Microsoft Windows 7, show errors, such as
when a network cable is unplugged.

Troubleshooting Configuration Problems

After confirming that your hardware is working properly, examine your networking
configuration to determine whether there is a misconfiguration of IP addresses, subnet
masks, or broadcast addresses. Common configuration problems can be caused by
misconfiguring newly connected or configured devices.

Determining Your IP Address

An IP address uniquely identifies computers and computing devices, such as the cable
modem, on a TCP/IP network. IP addresses are normally expressed in dotted-decimal
format, with four numbers (or "octets") separated by periods, such as 192.168.100.1 .
For troubleshooting purposes, all the numbers in the IP addresses of your networked
devices must be consistent across the network. This means:
The first nine numbers (i.e., the first three octets) in the IP addresses are the same for all

the devices on the network.
The last three numbers (i.e., the last octet) in the IP addresses are different and not in

use by other devices on the network (assuming your subnet mask is
255.255.255.000 ).
For example, if the IP address for the cable modem is 192.168.100.1 , the other devices
on the network must have an IP address whose:
First three octets are 192.168.100 .

Last octet is any unique number from 0 to 255 (there are restrictions on using 0 and 255 ,

so avoid using them). You would not use 1 as the last number, since that number is the
last octet in the cable modem IP address in our example.
Note: Since this device is bridging cable modem a PC directly connected to it will be assigned
a dynamic IP address by your cable operator. You will need to use a separate stand alone
router to create a home network.
Figure 5-1 shows an example of IP addresses assigned to devices on the network.
D3CM1604 DOCSIS 3.0 Cable Modem Administrator Manual
Troubleshooting Procedures
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