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Author Topic: File disconnection or denial of service issue  (Read 255 times)

TimR

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File disconnection or denial of service issue
« on: March 15, 2024, 10:34:11 AM »
I'm getting random errors where my nettalk webserver program(multisite/multi-dll) will say it can't find some mssql file (not consistent which file is picked), then crash. Does that sound like it is a file disconnection issue, it might run for days or hours before the problem manifests.

It might be related to friendly people hammering the server with many requests trying to gain access, which also happens frequently. Anyone have any tips on how to deal with the bad actors trying to gain access. While blocking IP's via firewall, works, something a bit less manual would be handy. There are way more IP's available then I care to deal with 1 by 1


Bruce

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Re: File disconnection or denial of service issue
« Reply #1 on: March 15, 2024, 11:47:36 PM »
>> Anyone have any tips on how to deal with the bad actors trying to gain access.

Ignore them.
(Incidentally they likely have zero effect on your database connections.)

>> I'm getting random errors where my nettalk webserver program(multisite/multi-dll) will say it can't find some mssql file (not consistent which file is picked), then crash.

They are not random, you just haven't spotted the pattern yet. Continue gathering information though - once you recognize the pattern it becomes a lot easier to duplicate, and fix.

>> Does that sound like it is a file disconnection issue, it might run for days or hours before the problem manifests.

sure it sounds like it. Whether it is is or not is difficult to say. Have you implemented any prop:disconnect techniques?

Cheers
Bruce

TimR

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Re: File disconnection or denial of service issue
« Reply #2 on: March 18, 2024, 09:30:54 AM »
I have not implemented any prop:disconnect techniques, I spent some time searching for them, but they appear to be in an old (2020?) CIDC conference session, so I didn't have any idea what they were about. I will continue looking.

Jane

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Re: File disconnection or denial of service issue
« Reply #3 on: March 18, 2024, 10:14:56 AM »
I've implemented the old SQL disconnect stuff Rick described in the old 2020 CIDC conference and it works brilliantly.

Generally, Clarion apps share a single SQL connection across threads.  Rick creates a separate transitory connection as each new p_web thread needs it.
It does add some SQL overhead because of his approach to the frequency with which it disconnects, but that doesn't impact my apps negatively.

You could, of course, modify Rick's approach and just disconnect prophylactically at times you feel appropriate.


Stu

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Re: File disconnection or denial of service issue
« Reply #4 on: March 18, 2024, 03:33:53 PM »
For a long time I had trouble with disconnects, or what looked like disconnects.

I implemented the "disconnect after X period of time inactivity" - whatever "inactivity" consists of (I think I use some of the nettalk webserver counters that Bruce showed me).

Also looked into Rick's solution, which is awesome (but that I couldn't get working, and on zooming with Rick discovered it wasn't going to solve what the root issue looked like).

In the end, what (completely) solved the specific sql connection issues I was facing was upgrading my Clarion 11 to the latest version.

At some point between the version I had and the latest, one or more SQL bugs were squashed that resolved what was plaguing my websever instances.

--

The user story was that they would be working and the system would "Freeze".

On investigation, at a time I was logged in and active, it was clear that there was a threading/connection situation going on, as you could navigate around to some places in the portal, but others would hang.

This along with discussions with Bruce and Rick, led me to upgrade my Clarion - which ended up solving this particular thing.
Cheers,

Stu Andrews