0

I have some software which is consuming information from various other systems that we control.

One of the servers running our software has suddenly stopped talking to two of our sets of services, and gives an error:

The underlying connection was closed: A connection that was expected to be kept alive was closed by the server

On each client server, we have two pieces of software running, Product X and Product Y. We have two central services running that these connect to - X connects to Services A & B, Y connects to A only.

On every server we have, bar one, everything connects and runs as expected.

Over the last weekend, one of our clients has been having an issue and product X is unable to connect to Service B, and Y cannot connect to A. X can still connect to A and take data from there.

I have created various test applications to run on the server which will connect to the services, put up known data and get known data back. Connecting to Service B fails, but it can connect to Service A, despite being an almost exact copy of the code from Product Y (The main code is the same, the code to access the database to get settings has been replaced with hard coded test values)

Nothing has changed on our servers hosting the two services. We have been told that nothing has changed on the client server. A firewall change was made elsewhere on the network to block HTTP to one server. Our services are on HTTPS, and I would assume that a firewall rule would affect all the web service access, not with the consistant mixed behaviour that I have now.

The software on the client is targetting .NET 4.5, the services are both .NET 4.0

We have run tests on other clients and they are not experiencing anything.

What I have tried so far: Testing on other servers (They are fine) Testing connection from affected server (Reliably have one test pass and one test fail) Google/StackOverflow (Many posts from a long time ago about .NET 1.1)

Paul Evans
  • 17
  • 6
  • 1
    That reads to me as "It was working..." "A firewall change was made"... "It isn't working now". Can the firewall change be temporarily reversed just to confirm that it didn't make any difference? – Andrew Morton Jan 23 '19 at 11:17
  • ...maybe it will come out that you have always created HTTP connections instead of HTTPS. Try to align/update your Frameworks (to 4.5.2+) – Jimi Jan 23 '19 at 11:29
  • Just found a potential problem - saw the configuration for one of the pieces of software ahd been reconfigured to use HTTP and not HTTPS. Changing the test app to go from HTTPS to HTTP gave me that error - this does make me think the firewall rule is causing us the problem. Been scratching my head for two days on this, and then get a lightbulb moment immeditely after asking here, typical – Paul Evans Jan 23 '19 at 11:31
  • Jimi has it on the nose – Paul Evans Jan 23 '19 at 11:35

0 Answers0