User`s guide

Return Format
The query command returns the Subnet Mask in the form
"nnn.nnn.nnn.nnn".
Note that the query command has two optional parameters. Specify
"CURRent" (default) to read the dynamic Subnet Mask currently being used
by the instrument. Specify "STATic" to read the Subnet Mask currently
stored in non-volatile memory within the instrument (may not be the actual
mask used by the instrument if DHCP is enabled).