I have a simple network built using:

  • 1 Switch (16-Port Gigabit Easy Smart Switch)
  • 4 Windows 10 PCs (Used as kiosks, with a custom software application)
  • 1 Windows 10 PC (Used as a SQL Server)
  • 10 custom boards (They respond to ARPs, ICMP, and send small data across the network)

All the PCs and boards are setup with static IP addresses and the PCs have an extra adaptor that connects them to the internet (Edit on different IP address ranges and subnets).

Within my application I'm intermittently getting an error: a network related or instance specific error occurred while establishing a connection to sql server. the server was not found.

I believe there is some sort of instability/high utilisation going on within the network but can't for the life of me figure out how to diagnose it?

What steps can I take or tools can I use to find out the root cause of this issue?

Edit: Both networks are on different subnets and IP Ranges (192.xxx and 172.xxx - We use the 192 network for custom boards, 172 for internet)

Edit: I've tried using Wireshark to attempt to find a bottle neck in the network but I don't know what steps to take to setup and monitor the throughput or utilization.

  • Have you tried some of the following suggestions by others on here who have experienced similar: stackoverflow.com/questions/18060667/… – Kinnectus Jan 30 '18 at 7:34
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    OK. Do you notice the problem with any specific configuration of your network... such as, you say some of the clients are also connected to the internet - are any of the connections giving the same IP to one of the clients. Have you tried changing your static IP range/subnet? You may also want to consider manually configuring the network adapter speeds because auto negotiation may be causing some issues. Manually set them to, say, 100Mbps/Full Duplex then up it to gigabit and trial and error to see if the problem occurs more at one speed than another. – Kinnectus Jan 30 '18 at 7:38
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    Edit your question to provide this information so others don't question it :) – Kinnectus Jan 30 '18 at 7:41
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    I suggest to download Wireshark (free to use)! With its help you might be able to determine the answer to some of your questions. – Hannu Jan 30 '18 at 13:59
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    Zach67 was asking if the traffic was crossing the network boundaries. I.e is the server is in 172.x and the clients in 192.x. in addition please edit your post so we can see the full network IP addresses with subnet masks. IP addresses are uninterruptible without the mask. It's essentially the key to understanding where the network starts and ends. – Tim_Stewart Feb 16 '18 at 19:29

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