hwDHCPSGlobalPoolOptionHexString
1.3.6.1.4.1.43.45.1.5.7.2.1.4.1.4
Hex string of an option. 1st to 16th hex strings,
which are 2 bytes, 4 bytes, 6 bytes or 8 bytes,
can be configured at most simultaneously.
That means the format of each string
must be '12', '1234', '123456' or '12345678'.