JANOS Help System: [Commands] [Topics] [Tech Support] [Printable Manual] [Search]
Basics Networking NETWORKING A JNIOR must be properly configured to participate reliably on the local network. Network configuration can be quite complex and a great deal of planning often goes into the structuring of commercial networks. While the IT Department or appropriate networking professionals should be consulted when adding devices like the JNIOR to a network, some relatively simple concepts are all that are needed to get the JNIOR up and running. The JNIOR is a wired network device. While WiFi and Cellular adapters are available to provide the JNIOR with such connectivity, the device is typically connected to a Network Switch via a CAT5 cable. Any number of computers, printers and devices connected to a network switch or multiple switches constitutes a Local Area Network or LAN. The connected devices can all message one another. A Wireless Access Point provides wireless connectivity and is at some overly simplified level just a big multi-port network switch in the sky. WiFi extends the wired network and all devices both wired and wireless are able to communicate with one another. A Wireless Router often serves on the local network side as a network switch with wireless access. The router has another connection allowing it to be connected to another network which is often referred to as the Wide Area Network or WAN. ETHERNET MAC ADDRESS Just as when someone wishes to send you a letter they need your postal address or when they send you an email they need your email address, a machine on the LAN can send another a message if it knows its Media Access Control or MAC address. This is an address like 9c:8d:1a:00:07:f9 and is something that thankfully you never really need to know. On the wire though that MAC address is absolutely necessary to get packets of information from one place to another. Of importance is that every device manufactured should have a unique MAC address permanently programmed. Each JNIOR has a unique address and the prefix 9c:8d:1a is assigned to INTEG. This can be used to identify all of the Series 4 JNIOR products on a network. IP ADDRESSING As opposed to the MAC address the address that you do need know to communicate with devices locally and outside is the Internet Protocol address or IP Address. This is an address that looks something like which is not all that easy to remember either. Typically the first three numbers (or octets) displayed here are consistent for every device on the LAN. Only the last octet varies. On the network, and very much in the background, there is a procedure for finding the MAC address for any destination with an IP address. You need not know much more about it. While a JNIOR may be assigned any IP address it has but one MAC address. Units are labeled with the programmed MAC address and this can also be obtained by using the IPCONFIG command in the Command Line Console. CLIENT vs. SERVER When you open your Browser and enter a URL it is typically some text like https://jnior.com In this case you are a Client and are attempting to connect to a Server located at INTEG. Fortunately you do not need to know the IP Address in order to make the connection. You will want to use the browser to access the JNIOR. In this case you will need to know its IP address. The URL would look like: IP SETTINGS To properly configure the JNIOR for the network there are 2 critical IP settings and 3 fairly important settings. These are as follows: 1. IP Address 2. Subnet Mask 3. Gateway Address 4. Primary DNS 5. Secondary DNS If you are uncertain as to the proper settings for your network you may try the Dynamic Host Conbfiguration Protocol (DHCP). Most routers enable this protocol. This helps computers join the network and properly configure. The JNIOR now ships with DHCP enabled. DHCP can be enabled from the command line with the following command: ipconfig -d In the Support Tool it is a selection. Right-click on the JNIOR in the Beacon tab and select Configure and then IP Configuration . There is a selection to enable DHCP. After a minute if DHCP is available the JNIOR will acquired a valid network setup. You can then check the IP configuration through the Support Tool or by using IPCONFIG. This will give you items 2 thru 5 in the above list. DHCP IP addresses themselves are leased . While it is likely that the JNIOR will retain the assigned IP address for some time, that address is assigned from a pool (range of addresses) and can change. Since you need the IP address to communicate with the JNIOR you don't need it to be a moving target. The solution is then to disable DHCP and assign a fixed IP address which should be outside of the DHCP range. You will need to get that address from your network administrator. In a pinch you can use the ARP -S command to locate a low numbered unused address. The ARP command scans the network and reports any addresses that actively respond. You can then disable DHCP again using the Support Tool or with the following command: ipconfig -r The JNIOR will retain the DHCP configuration. It is important to reassign the IPv4 address outside of the DHCP range either using the Support Tool or command. For example: ipconfig -a SUBNET MASK It was mentioned that the first 3 numbers or octets of IP addresses on the local network typically all match. The local network must use only a small range of all possible IP addresses as those outside of the range are then used to access hosts and devices all over the world. The local address scheme uses an address range typically reserved for individual local networks. The Subnet Mask defines the portion of the IP address that must match that assigned to the JNIOR for any local network participant. This is a bit mask specifying bit by bit from the left (most-significant bit) the bits that must match between source IP address (the JNIOR) and destination. So with a typical local network a subnet mask of indicates that all of the bits in the first 3 octets must match for local communications. With 8 bits per octet (byte) there are 24 bits from the left than must match. You may also see the IP address specified as for example . When the destination address DOES NOT match in every indicated bit position the destination is assumed to be outside of the local network. The source then attempts to contact the destination using the Gateway device. The gateway then potentially providing access to the Wide Area Network and hopefully the host destination. The Subnet Mask can be set using the Support Tool or using IPCONFG. In these command examples the latter sets both the IP Address and Subnet Mask in one step. ipconfig -s ipconfig -a If you erroneously set the Subnet Mask, communications may fail to reach some members of the local network or some external hosts. This may depend on the operation of the gateway which might optionally assist in properly locating the destination as still being on the local network. Basically, the subnet mask typically is set identically for all members of the local network. More complex network topologies are possible. It is best to consult your network administrator. GATEWAY The Gateway is a device on the local network that also is a member of another network. The latter being presumably connected to the Wide Area Network and ultimately possibly the Internet. The Gateway then is likely the router for the local network. It serves as a bridge to the outside world. If a Gateway address is not properly defined the JNIOR will not be able to contact hosts outside of the local network. In a typical automation scenario it may not seem that the JNIOR would have any reason to communication outside of the local network. The JNIOR periodically reaches out to a NTP server in order to synchronize its clock. This occurs about every 4 hours and relies on proper Gateway settings and DNS. The JNIOR can also be configured to send email notifications. For this to be possible the unit also needs to access the outside world. It is important to properly define the Gateway IP address. DNS SETTINGS The Domain Name System is a huge distributed database spread across the Internet. Its basic function is to translate a domain name like those you use in URLs to IP addresses. You use a DNS server to convert the website jnior.com to the INTEG IP address so that behind the scenes your computer can communicate with the company's server and the browser can render the website. While the JNIOR does not support a browser it is configured with domain names that it will need to convert to IP addresses from time to time. In particular the JNIOR synchronizes its clock with an external NTP Server. The NTP server is located by first requesting an IP address from a DNS server for the domain: pool.ntp.org There are other NTP services that you can use. This one selects from a large pool of available NTP servers and offers an IP address for one that can best service your location. With a DNS server properly specified the DATE command can reach out and synchronize. For example: bruce_dev /> date -n Requesting time sync from pool.ntp.org ( Clock synchronized by NTP Wed Jul 28 11:28:51 EDT 2021 bruce_dev /> Note here that pool.ntp.org has been resolved to the address and that the JNIOR successfully synchronized its clock. There are two DNS addresses, a Primary and a Secondary . A DNS server may get too busy to respond or may be down for service. It is critical to have a backup. We specify a primary and a secondary DNS server address in hopes that at least one of the two is available to help us. The JNIOR may try the primary first and if there is no timely response attempt to use the secondary. It may also just ask both and take the first response and run with it. The NSLOOKUP command can be used to resolve domains. For example: bruce_dev /> nslookup jnior.com Issuing DNS request (<0.1s) Inet Addr Domain jnior.com bruce_dev /> If DNS addresses are not defined or if the DNS Servers cannot be reached the JNIOR clock will likely drift away from the correct time. This may only affect the timestamps that appear in logs. If the application is performing tasks on a schedule those events may not occur on time. Email notifications if configured will not be deliverable. You might use the Google public DNS addresses and although there are many other servers available. SUMMARY For proper network use the JNIOR needs 1) a unique IP Address valid for the local network; 2) A proper Subnet Mask for the local network; 3) A Gateway IP Address for access to the outside world; And, 4) at least one valid DNS server address. DHCP can be a valuable tool for discovering settings for all but the IP address itself. Finally, the IP Address must be uniquely defined for each device on the network. The JNIOR will query for conflicts during boot. If the IP address assigned to the JNIOR is claimed by another device on the network the JNIOR will not be available. In this case it will report an IP Address of and will remain accessible through the Support Tool for reconfiguration. SEE ALSO HELP Topics: IPCONFIG, ARP, NSLOOKUP, DATE [/flash/manpages/manpages.hlp:581]