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Hey All, I’m here again, this time with a strange question… We maintain the IT infrastructure in a school. We have multiple buildings in the school campus. We have a PRIVA Systems - HVAC building automation system & remote controller (industrial PC’s). In one building, lets say the main building, we have the main automation system to manage the HVAC, it controls al the heating and air flow systems. The maintenance engineers can remotely log in into the system via TeamViewer app or Windows Remote desktop from a system in our maintenance office which we can likewise manage the system. From the beginning we have had problems with the office system and only that one PC. Sometimes the PC looses the connection with internet, yet the PC is still running. We can’t ping the PC and we can’t connect by RDP nor can we connect by TeamViewer app either… nothing. It has a fixed IP address, all settings are normal… no strange errors or whatever in the logs… The PC went back to the manufacturer, they checked it over a time of 2 months… in that time we hooked up an other PC with the same settings as the original… and guess what! No problems at all !! The manufacturer didn’t find anything on there side as well… Now the big issue is: They say (firm that installed the industrial PC): It is your fault if the device is’t running properly cause it is an internal network issue… We can’t find anything .. the strange thing is that the laptop workes fine with the same settings… The industrial PC (PRIVA SX100) runs normal over several weeks, than suddenly no connection, sometimes it runs for 2 days, sometimes 4 … before the “error” occurs.. What is your suggestion? okay we can replace the %#*@ thing .. but we have to find the problem so we can explain it to several interested parties. (and pay the cheque or…. :) ) Can I check a specific log? … All the power options are set to never sleep. Also the network adapter power options are set to never sleep. There is one thing that I noticed : We saw that the secondary DNS was causing trouble, so we deleted it and only fill in the primary DNS what is, in this case, the same as the default gateway. Secondary DNS is given by the ISP. When we removed the secondary, the PC was going well, when it failed again and rebooted the pc, we saw that the secondary DNS was back… how is this possible? Can this be the major problem? Thanks in advance!
You could have a few possible issues here: The first is your IP addressing of your internal network may create an issue. Lets say you are using non-Routable addressing (Private Network) internally and your PRIVA automation system which is in the boiler rm has a fixed IP address in the address block you are using. Now the network path between the boiler rm and your office needs to be checked out. Ideally, you have a direct connection (no routers or switches) to the hub your office PC is sitting on. If you can’t achieve that then make sure you only have layer 2 switching (no routing) devices between the two systems. Now within your management PC create a host file with the IP address and the host name. So now the systems routing tables see’s this connection as a direct connection (same IP subnet on a flat network). Now lets move on… Your management PC in your office likely has a DHCP address assignment. Thats fine but you’ll want to reserve the IP address within the DHCP server (if you want you can also do this with the boiler system). That way the DHCP server won’t alter the settings which could have messed you up. Ref: What Is DHCP Now the bully in the room! Windows its self has a name service WINS. I Like to say you WINS you lose! As I hate it! It always messes you up as the pecking order is WINS first then it will fall over to IP name services (Host & DNS). What can happen is the WINS DB can get corrupted and depending on what you assign your systems for names it can confuse the lookup. So what I do is use a different name for the Windows systems (for WINS) than the TC/IP name I assign for the same system as an example ’ wacme-school.com’ and ‘acme-school.com’ That way WINS is bypassed! Ref: Windows Internet Name Service (WINS) Overview As to gaining access to the Internet from this system (outwards) your DHCP settings should be fine setting the nearest routers IP address as your gateway and DNS, then use the helper function within the router to forward the request to your DNS in-house (that is if you have one) and then the ISP’s DNS. As to the reverse, gaining access to the PRIVA automation system from the Internet. I would recommend you do this through a VPN tunnel so you can control who is gaining access to the system (either one) and I would recommend you limit access if you can to the office system only (not the system in the boiler rm). Then piggy back the connection over to the PRIVA automation system in the boiler rm. That way you have a second door before someone can gain access to the system (you never know these days…) and limit it to as few people as needed (don’t forget to alter the passwords for everyone if someone leaves! and delete their systems account and VPN access as well). As to how to monitor things… You’ll need to setup an RMON probe to pole the systems (not to often now!) Then review its logs for what happened. Ref: RMON Last piece here.. As you have multiple buildings one of the issues you can encounter is a ground loop. Review with your cabler the ANSI/TIA-607-B Generic Telecommunications Bonding and Grounding (Earthing) for Customer Premises You may want to ask them if they have BICSI certified people on their staff. You may need to have a power meter probe setup across the buildings to monitor each buildings ground.
