Guralp Systems CMG-DCM build <10,000 - Manual (Page 79)

Acquisition Modules and Platinum Firmware Networking Configuration
7.2.2.1 Network
MTU: This field allows you to define a Maximum Transmission Unit (the size
of the largest packet that a network protocol can transmit) for the associated
network. A value which is too small will cause inefficient packetisation
whereas one which is too large will cause packet fragmentation and possible
disruption to communication. See the discussion in section 7.1.2 on page 72
for more information.
7.2.2.2 IP Address
Extra dhcpcd options: Used to change the operation of the DHCP client.
Please see
http://man-wiki.net/index.php/8:dhcpcd for information about what
options can be added here.
MAN-EAM-0003 79 Issue E - February 2014