ZyXEL Communications ZyWALL 5 User Manual page 74

ZyWALL 5 Internet Security Appliance
LABEL
RIP Version The RIP Version field controls the format and the broadcasting method of the RIP
packets that the ZyWALL 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.
Multicast Select IGMP V-1 or IGMP V-2 or None. IGMP (Internet Group Multicast Protocol) is a
network-layer protocol used to establish membership in a Multicast group - it is not used
to carry user data. IGMP version 2 (RFC 2236) is an improvement over version 1 (RFC
1112) but IGMP version 1 is still in wide use. If you would like to read more detailed
information about interoperability between IGMP version 2 and version 1, please see
sections 4 and 5 of RFC 2236.
DHCP Setup
DHCP Server DHCP (Dynamic Host Configuration Protocol, RFC 2131 and RFC 2132) allows individual
clients (workstations) to obtain TCP/IP configuration at startup from a server. Unless you
are instructed by your ISP, leave the DHCP Server check box selected. Clear it to stop
the ZyWALL from acting as a DHCP server. When configured as a server, the ZyWALL
provides TCP/IP configuration for the clients. If not, DHCP service is disabled and you
must have another DHCP server on your LAN, or else the computers must be manually
configured. When set as a server, fill in the rest of the DHCP setup fields.
IP Pool Starting This field specifies the first of the contiguous addresses in the IP address pool.
Address
Pool Size This field specifies the size, or count of the IP address pool.
DNS Servers Assigned by DHCP Server
The ZyWALL passes a DNS (Domain Name System) server IP address (in the order you specify here) to the
DHCP clients. The ZyWALL only passes this information to the LAN DHCP clients when you select the DHCP
Server check box. When you clear the DHCP Server check box, 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.
First DNS Server Select From ISP if your ISP dynamically assigns DNS server information (and the
ZyWALL's WAN IP address). The field to the right displays the (read-only) DNS server IP
Second DNS
address that the ISP assigns.
Server
Select User-Defined if you have the IP address of a DNS server. Enter the DNS server's
Third DNS Server
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 ZyWALL act as a DNS proxy. The ZyWALL's LAN IP
address displays in the field to the right (read-only). The ZyWALL tells the DHCP clients
on the LAN that the ZyWALL itself is the DNS server. When a computer on the LAN
sends a DNS query to the ZyWALL, the ZyWALL forwards the query to the ZyWALL's
system DNS server (configured in the MAINTENANCE 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 computer in order to access it.
4-4
Table 4-1 LAN
DESCRIPTION
LAN Screen