ZyXEL Communications 650 User Manual

Page of 215
Prestige 650 ADSL Router 
3-2 
 
Internet Access 
 
Figure 3-1 LAN & WAN IPs 
 
3.3 TCP/IP 
Parameters 
3.3.1  IP Address and Subnet Mask 
Like houses on a street that share a common street name, the computers on a LAN share one common 
network number. 
Where you obtain your network number depends on your particular situation.  If the ISP or your network 
administrator assigns you a block of registered IP addresses, follow their instructions in selecting the IP 
addresses and the subnet mask. 
If the ISP did not explicitly give you an IP network number, then most likely you have a single user account 
and the ISP will assign you a dynamic IP address when the connection is established.  If this is the case, it is 
recommended that you select a network number from 192.168.0.0 to 192.168.255.0 (ignoring the trailing 
zero) and you must enable the Single User Account feature of the Prestige. The Internet Assigned Number 
Authority (IANA) reserved this block of addresses specifically for private use; please do not use any other 
number unless you are told otherwise.  Let’s say you select 192.168.1.0 as the network number; which 
covers 254 individual addresses, from 192.168.1.1 to 192.168.1.254 (zero and 255 are reserved).  In other 
words, the first three numbers specify the network number while the last number identifies an individual 
computer on that network. 
The subnet mask specifies the network number portion of an IP address.  Your Prestige will compute the 
subnet mask automatically based on the IP address that you entered.  You don’t need to change the subnet 
mask computed by the Prestige unless you are instructed to do otherwise.