3
Features and Functions
110
Keysight 34980A Mainframe User’s Guide
Subnet Mask
The instrument uses the Subnet Mask to determine if a client IP address is on the
same local subnet. When a client IP address is on a different subnet, all packets
must be sent to the Default Gateway. Contact your network administrator to
determine if subnetting is being used and for the correct Subnet Mask.
If you change the Subnet Mask, you must cycle power on the 34980A to activate
the setting.
– The default Subnet Mask for the 34980A is “255.255.0.0”.
– If DHCP is enabled, the specified Subnet Mask is not used. However,
if the DHCP server fails to assign a valid IP address, the currently configured
Subnet Mask will be used.
– Dot-notation addresses (“nnn.nnn.nnn.nnn” where “nnn” is a byte value) must
be expressed with care, as most web software on the computer will interpret
byte values with leading zeros as octal numbers. For example,
“255.255.020.011” is actually equivalent to decimal “255.255.16.9” not
“255.255.20.11” because “.020” is interpreted as “16” expressed in octal, and
“.011” as “9”. To avoid confusion, use only decimal expressions of byte values
(0 to 255), with no leading zeros.
For example, the 34980A assumes that all dot-notation addresses are
expressed as decimal byte values and strips all leading zeros from these byte
values. Thus, attempting to set a Subnet Mask of “255.255.020.011” will
become “255.255.20.11” (a purely decimal expression). Be sure to enter the
exact expression, “255.255.20.11”, in your computer web software to address
the instrument. Do not use “255.255.020.011” — the the computer will
interpret this address differently due to the leading zeros.
– A value of “0.0.0.0” or “255.255.255.255” indicates that subnetting is not being
used.
– The Subnet Mask is stored in non-volatile memory, and does not change when
power has been off, after a Factory Reset (
*RST
command), or after an
Instrument Preset (
SYSTem:PRESet
command).
Front Panel Operation:
Utility > REMOTE I/O > LAN > LAN SETTINGS > MODIFY > DHCP OFF >
AUTO IP OFF > . . . SUBNET MASK
Remote Interface Operation:
SYSTem:COMMunicate:LAN:SMASk "<
mask
>"