To change the IP address(es) of this device, make the applicable entries and click Apply. The "automatic" selection means DHCP. Changes to the IPv4 IP address will take effect upon the next system restart.

If IPv6 is enabled, IPv6 will always have a Link-Local address, plus one configured address. The configured address will be either the static IP address, or an IPv6 address obtained from an IPv6 DHCP server. If no configured address appears, the DHCP server may have been unreachable.

The IPv6 static IP address window is the configured static address. If "Static" is selected and a new IP address entered as the static address, this new address will not take effect until the next system restart.

NTP setup: Enter a primary and secondary IP address of NTP server, such as 24.56.178.140 for wwv.nist.gov (go to http://tf.nist.gov/tf-cgi/servers.cgi to find more). Enter daylight start/end rules, and offset from GMT for both standard and daylight time. Offset is a negative number in the western hemisphere. Enter an NTP update time in minutes. Do not set NTP to update too frequently or you risk being denied service by the NTP server. Click the Set NTP button after all settings have been made. The Flash update will take several seconds.

Daylight savings time start/end rules consist of "date/time" where the date (m.n.d) indicates the day when summer time starts or ends, and time (hour:min:sec) is the current local time when summer time starts/ends. The date portion of the rule is formatted as follows:

• m indicates the month (1 <= m <= 12)
• n indicates which week of the month (1 <= n <= 5). 5 = the last week in the month.
• d indicates what day of the week (0 <= d <= 6). 0 = Sunday

For example: Start "4.1.0/02:00:00", end "10.5.0/02:00:00" means summer time starts at 2am on the first Sunday in April and ends at 2am on last Sunday in October. That was the old US rule. The new US rule is start "3.2.0/02:00:00" and end "11.1.0/02:00:00", which is start at 2am on the second Sunday in March, end at 2am on the first Sunday in November.

You may use domain names instead of static IP addresses in several instances. If domain names are used, you must supply the IP address of at least one DNS server here. The DNS server must be at a static IP address. These changes take effect immediately. Note: If you are using DHCP, the DNS addresses will be supplied by the DHCP server and should be set to 0.0.0.0 here.

The numbers shown to the right of input windows are the actual numbers in the system. For example, entering an IP address of 255.255.255.255 causes the system to acquire a dynamic IP address via DHCP. The IP address shown to the right is the currently leased IP address. When DHCP is used, static DNS entries are ignored, and the actual DNS entries provided by DHCP are shown.

The default port for web page serving is 80. If you wish to change it, enter the port number and click Set Port. This change will take effect upon the next power-up. If the port is anything other than 80, you must include the port number in the URL. For example, if you would normally use http://10.0.0.101/ to get here and you change the port to 8215, you would now use http://10.0.0.101:8215/. (Note: The port change is only accepted if you are logged in as the root user.)

The default port for the Modbus TCP server is the standard port 502. Set to a different port number if applicable. Set to zero to disable the Modbus TCP server, thereby blocking Modbus TCP access to this device.