1. How the IRTF 192.168 networks works 192.168.0.0/16 is a "private network" within the IRTF and Hilo subnet. Private IP devices can only be access with computers that addresses the 192.168.0.0/16 nic interface. The subnetmask is 255.255.0.0 proving 65537 addresses. The IRTF has control of the 192.168.0 to 192.168.10 providing about 2450 addresses. Also we use 192.168.165.x, 192.168.110.x so workstaion can have similiar IP as their public interface, ie: t1hilo will use 128.171.165.120 & 192.168.165.120. The 192.168.x.x NIC interface can be added to a CentOS6 computer by creating a /etc/sysconfig/network-scripts/ifcfg-eth0:1 with the following entries: (of course the IPADDR, HWADDR is machine dependent). DEVICE=eth0 BOOTPROTO=none TYPE=Ethernet ONBOOT=yes IPADDR=192.168.110.151 PREFIX=16 NETMASK=255.255.0.0 HWADDR=90:2B:34:A1:51:D4 Then, /etc/init.d/network restart (but reboot is better). "ifconfig -a " does not show 2nd interface, but "ip addr show" does. 1. TCS info In Apr 2015, TCS started using the 192.168 inteface. The t1, t2, t1hilo eth0 was setup with the 192.168.x.x IP value. TCS 1st 192 controller would be the 192.168.2.1 isdth-001 # omega.com iSD-TH temp, humidity controller; denault This IP controller would replace the broken Vaisala HMT300 unit that was directly wired to the FIO units.