ZyXEL Communications VANTAGE CNM User Manual page 79

Table 17 Configuration > LAN > IP – ZyWALL (continued)
LABEL
First DNS Server
Second DNS
Server
Third DNS Server
TCP/IP
IP Address
IP Subnet Mask
RIP Direction
RIP Version
Chapter 5 Configuration > LAN
DESCRIPTION
Domain Name System is for mapping a domain name to its corresponding IP
address and vice versa. The ZyXEL device passes a DNS (Domain Name
System) server IP address (in the order you specify here) to the DHCP clients.
The ZyXEL device only passes this information to the LAN DHCP clients when
you select DHCP Server. If you don't select DHCP Server, DHCP service is
disabled and you must have another DHCP sever on your LAN, or else the
computers must have their DNS server addresses manually configured.
Select From ISP if an ISP dynamically assigns DNS server information (and the
ZyXEL device's WAN IP address). The field to the right displays the (read-only)
DNS server IP address that the ISP assigns.
Select User-Defined if you have the IP address of a DNS server. Enter the DNS
server's IP address in the field to the right. If you chose User-Defined, but leave
the IP address set to 0.0.0.0, User-Defined changes to None after you click
Apply. If you set a second choice to User-Defined, and enter the same IP
address, the second User-Defined changes to None after you click Apply.
Select DNS Relay to have the ZyXEL device act as a DNS proxy. The ZyXEL
device's LAN IP address displays in the field to the right (read-only). The ZyXEL
device tells the DHCP clients on the LAN that the ZyXEL device itself is the DNS
server. When a computer on the LAN sends a DNS query to the ZyXEL device,
the ZyXEL device forwards the query to the ZyXEL device's system DNS server
(configured in the SYSTEM General screen) and relays the response back to the
computer. You can only select DNS Relay for one of the three servers; if you
select DNS Relay for a second or third DNS server, that choice changes to None
after you click Apply.
Select None if you do not want to configure DNS servers. If you do not configure
a DNS server, you must know the IP address of a machine in order to access it.
Type the IP address of the ZyXEL device in dotted decimal notation. 192.168.1.1
is the factory default.
The subnet mask specifies the network number portion of an IP address. The
ZyXEL device automatically calculates the subnet mask based on the IP address
that you assign. Unless you are implementing subnetting, use the subnet mask
computed by the ZyXEL device, which is 255.255.255.0.
RIP (Routing Information Protocol, RFC1058 and RFC 1389) allows a router to
exchange routing information with other routers. The RIP Direction field controls
the sending and receiving of RIP packets. Select the RIP direction from Both/In
Only/Out Only/None. When set to Both or Out Only, the ZyXEL device
broadcasts its routing table periodically. When set to Both or In Only, it
incorporates the RIP information that it receives; when set to None, it does not
send any RIP packets and ignores any RIP packets received. Both is the default.
The RIP Version field controls the format and the broadcasting method of the
RIP packets that the ZyXEL device sends (it recognizes both formats when
receiving). RIP-1 is universally supported but RIP-2 carries more information.
RIP-1 is probably adequate for most networks, unless you have an unusual
network topology. Both RIP-2B and RIP-2M sends the routing data in RIP-2
format; the difference being that RIP-2B uses subnet broadcasting while RIP-2M
uses multicasting. Multicasting can reduce the load on non-router machines since
they generally do not listen to the RIP multicast address and so will not receive
the RIP packets. However, if one router uses multicasting, then all routers on your
network must use multicasting, also. By default, RIP direction is set to Both and
the Version set to RIP-1.
Vantage CNM User's Guide
78