ZyXEL Communications Corporation IX280P Manual De Usuario

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Chapter 5 The LAN Configuration Screens
MAX-207HW2R User’s Guide
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The DNS server addresses that you enter in the DHCP setup are passed to the 
client machines along with the assigned IP address and subnet mask.
There are two ways that an ISP disseminates the DNS server addresses. The first 
is for an ISP to tell a customer the DNS server addresses, usually in the form of an 
information sheet, when s/he signs up. If your ISP gives you the DNS server 
addresses, enter them in the DNS Server fields in DHCP Setup, otherwise, leave 
them blank.
Some ISPs choose to pass the DNS servers using the DNS server extensions of 
PPP IPCP (IP Control Protocol) after the connection is up. If your ISP did not give 
you explicit DNS servers, chances are the DNS servers are conveyed through IPCP 
negotiation. The MAX-207HW2R supports the IPCP DNS server extensions through 
the DNS proxy feature.
If the Primary and Secondary DNS Server fields in the LAN Setup screen are 
not specified, for instance, left as 0.0.0.0, the MAX-207HW2R tells the DHCP 
clients that it itself is the DNS server. When a computer sends a DNS query to the 
MAX-207HW2R, the MAX-207HW2R forwards the query to the real DNS server 
learned through IPCP and relays the response back to the computer.
Please note that DNS proxy works only when the ISP uses the IPCP DNS server 
extensions. It does not mean you can leave the DNS servers out of the DHCP 
setup under all circumstances. If your ISP gives you explicit DNS servers, make 
sure that you enter their IP addresses in the LAN Setup screen. This way, the 
MAX-207HW2R can pass the DNS servers to the computers and the computers can 
query the DNS server directly without the MAX-207HW2R’s intervention.
5.6.5  RIP Setup
RIP (Routing Information Protocol) allows a router to exchange routing 
information with other routers. The RIP Direction field controls the sending and 
receiving of RIP packets.  When set to:
• Both - the MAX-207HW2R will broadcast its routing table periodically and 
incorporate the RIP information that it receives.
• In Only - the MAX-207HW2R will not send any RIP packets but will accept all 
RIP packets received.
• Out Only - the MAX-207HW2R will send out RIP packets but will not accept any 
RIP packets received.
• None - the MAX-207HW2R will not send any RIP packets and will ignore any RIP 
packets received.
The Version field controls the format and the broadcasting method of the RIP 
packets that the MAX-207HW2R sends (it recognizes both formats when 
receiving). RIP-1 is universally supported; but RIP-2 carries more information.