User's Manual
6) Security Configuration
This is to filter a certain IP addresses from accessing NetServer based on network masking.
(1) IP/Subnet Filtering Mode
You may allow or deny a certain user to access your NetServer with enabling this menu.
Default Policy
This is to decide the principle of ‘ IP/Subnet Filtering Mode’ between allow and deny.
If you allow anyone except a few users to access your NetServer, you should select default policy as
‘allow’ and register a few users as denied users. If you deny all users except a few users to access
your NetServer, you should select default policy as ‘ deny’ and register a few users as allowed users.
How to register allowed/denied user in the list
Network masking is to mask network ID for every existing IP address in the world. Therefore the IP
addresses that have the same network ID are to be applied with a command of ‘ Allow’ or ‘ Deny’ .
The masked bits are considered as network ID.
If a masking number is 4, the 4 bits from the first bit are masked as network ID comparing with the
provided IP address before, and any IP address that has the same binary number on the first 4 bits
are to be filtered from NetServer.
Note: To explain and understand easily on IP address, the first byte of IP address is marked as X1 in
this manual. And X2 is for the second byte, X3 is for the third byte, and X4 is for the fourth byte.
IP address is constructed as follows.
IP address construction in binary number of each bit
xxxxxxxx (8 bit): X1 xxxxxxxx (8 bit): X2 xxxxxxxx (8 bit): X3 xxxxxxxx (8 bit): X4
2
7
2
6
2
5
2
4
2
3
2
2
2
1
2
0
2
7
2
6
2
5
2
4
2
3
2
2
2
1
2
0
2
7
2
6
2
5
2
4
2
3
2
2
2
1
2
0
2
7
2
6
2
5
2
4
2
3
2
2
2
1
2
0
E.g. IP address in binary: 11000000. 10101000. 00000001. 00001101 (It is equal to 192.168.1.13)
* Binary number 1 means to take the equivalent decimal number (2
7
, 2
5
, etc) and 0 means to disregard it.
IP address construction in decimal number of each byte
xxx (0-255: 1 byte): X1 xxx (0-255: 1 byte): X2 Xxx (0-255: 1 byte): X3 Xxx (0-255: 1 byte): X4
128 64
32 16
8421128643216842112864321684211286432168421
IP address Masking Allow/Deny