ZyXEL 35 Guia Do Utilizador

 

 

All contents copyright (c) 2006 ZyXEL Communications Corporation.   

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If you are not able to get the Internet IP from the ISP, check which authentication method your ISP uses and 

troubleshoot the problem as described below. 

1. Your ISP checks the 'MAC address' 

Some ISPs only provide an IP address to the user with an authorized MAC address. This authorized MAC 

can be the PC's MAC which is used by the ISP for the authentication. So, if a new network card is used or 

the ZyWALL is attached to the cable modem directly, the ISP will reject the DHCP discovery from this 

MAC, thus no IP is assigned by the ISP. 

The ZyWALL supports to clone the MAC from the first PC the ISP installed to be its WAN MAC. To 

clone the MAC from the PC you need to enter that PC's IP in WAN menu of the ZyWALL web 

configurator. 

2. Your ISP checks the 'Host Name' 

Some ISPs take advantage of the 'host name' message in a DHCP packet such as @home to do the 

authentication. When first installing, the ISP's tech people configure the host name as the 'Computer Name' of 

the PC in the 'Networking' settings. When the ZyWALL is attached to the cable modem to connect to the ISP, 

we should configure this host name in the ZyWALL's system (menu 1).   

BOOTP stands for Bootstrap Protocol. DHCP stands for Dynamic Host Configuration Protocol. Both are 

mechanisms to dynamically assign an IP address for a TCP/IP client by the server. In this case, the ZyWALL 

Internet Access Sharing Router is a BOOTP/DHCP server. WinXP/2000 and WinNT clients use DHCP to 

request an internal IP address, while WFW and WinSock clients use BOOTP. TCP/IP clients may specify their 

own IP or utilize BOOTP/DHCP to request an IP address.   

 

The Dynamic DNS service allows you to alias a dynamic IP address to a static hostname, allowing your 

computer to be more easily accessed from various locations on the Internet. To use the service, you must 

first apply an account from several free Web servers such as 

WWW.DYNDNS.ORG

.  

Without DDNS, we always tell the users to use the WAN IP of the ZyWALL to reach our internal server. 

It is inconvenient for the users if this IP is dynamic. With DDNS supported by the ZyWALL, you apply a 

DNS name (e.g., www.zyxel.com.tw) for your server (e.g., Web server) from a DDNS server. The outside 

users can always access the web server using the www.zyxel.com.tw regardless of the WAN IP of the 

ZyWALL.  

When the ISP assigns the ZyWALL a new IP, the ZyWALL updates this IP to DDNS server so that the 

server can update its IP-to-DNS entry. Once the IP-to-DNS table in the DDNS server is updated, the DNS