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User Manual
Copyright © 3onedata Co., Ltd.
3onedata proprietary and confidential
71
NTP server can be empty, the device adopts self-contained server updating and must
ensure the correct configuration of DNS and gateway;
NTP server can’t be empty, it must be valid host name or legal IP address;
Only the “administrator” has the privilege to manually configure the device time.
12.3 Device Address
IP Address
The IP address is a 32-bit address assigned to the device connected to Internet. IP
address is composed of two fields: Network number field (net-id) and host number
field (host-id). IP addresses are allotted by the Network Information Center (NIC) of
U.S. Defense Data Network. IP addresses are divided into five categories for the
convenience of IP address management. As the table below:
Network Type
Address Range
Usable IP Network Range
A
0.0.0.0~126.255.255.255
1.0.0.0~126.0.0.0
B
128.0.0.0~191.255.255.255
128.0.0.0~191.254.0.0
C
192.0.0.0~223.255.255.255
192.0.0.0~223.255.254.0
D
224.0.0.0~239.255.255.255
-
E
240.0.0.0~246.255.255.255
-
Other
addresses
255.255.255.255
255.255.255.255
Thereinto, category A, B, C address are unicast address; category D address is
multicast address; category E address is reserved address for the future special
purpose. Now, most of the using IP addresses belong to category A, B, C address.
IP address adopts dotted decimal notation recording mode. Each IP address is
expressed as four decimal integers separated by radix point, each integer is
corresponding to a byte, such as 10.110.50.101.
Subnet Mask
A mask is 32 digits that corresponds to IP address, some of them are 1 and others are
0 in these digits. These 1 and 0 can be any combination in principle, but generally
when designing masks, set the first consecutive digits to 1. Mask can divide IP
address into two parts: subnet mask address and host address. The portion that
corresponds to the 1 in the IP address and mask is the subnet address, and the rest is
the host address. The corresponding mask of Class A address is 255.0.0.0; The