ICP DAS USA MSM-6226 - Manual (Page 43)

Publication date: March., 2011
Revision A1
31
Subnet mask is made for the purpose to get more network address
because any IP device in a network must own its IP address, composed
of Network address and Host address, otherwise can’t communicate with
other devices each other. But unfortunately, the network classes A, B,
and C are all too large to fit for almost all networks, hence, subnet mask
is introduced to solve this problem. Subnet mask uses some bits from
host address and makes an IP address looked Network address, Subnet
mask number and host address. It is shown in the following figure. This
reduces the total IP number of a network able to support, by the amount
of 2 power of the bit number of subnet number (2^(bit number of subnet
number)).
Subnet mask is used to set the subnet mask value, which should be the
same value as that of the other devices resided in the same network it
attaches.
For more information, please also see the Section 2-1-5 “IP Address
Assignment” in this manual.
Default: 255.255.255.0
Default gateway:
Set an IP address for a gateway to handle those packets that do not
meet the routing rules predefined in the device. If a packet does not meet
the criteria for other pre-defined path, it must be forwarded to a default
router on a default path. This means any packet with undefined IP
address in the routing table will be sent to this device unconditionally.
Default: 192.168.1.254
DNS:
It is Domain Name Server used to serve the translation between IP
address and name address.
The switch supports DNS client function to re-route the mnemonic name
address to DNS server to get its associated IP address for accessing
Internet. User can specify a DNS IP address for the switch. With this, the
switch can translate a mnemonic name address into an IP address.
There are two ways to specify the IP address of DNS. One is fixed mode,
which manually specifies its IP address, the other is dynamic mode,
which is assigned by DHCP server while DHCP is enabled. DNS can
help you easily remember the mnemonic address name with the
meaningful words in it. Default is no assignment of DNS address.
Default: 0.0.0.0
32 bits
Network ID Host ID
Network ID Host ID
Subnet number