[OPLINTECH] Sierra connection problem for 45 minutes this morning

[Chad Neeper]

I'm completely unfamiliar with your network, with the SDA client, its
server, etc. But in a scenario like this, I'd probably use Wireshark to
find out exactly what's going on between the client, the server, its DNS
lookups, etc. That will likely help quite a bit in determining exactly
where to look for the source of the problem. You'll be able to compare a
normal working condition against when the problem is happening. If the
client is making normal requests, but the server isn't responding in a
timely manner or with the normal responses, then you know to focus more on
the server side. If DNS isn't resolving with the expected addresses, you'll
know to look into DNS, etc. etc.

Watching how the network operates at a packet level is an immensely useful
skill to explore, if you haven't done that before. This could give you a
good opportunity to add that skill to your toolbox, if you haven't already
done so!

2 cents.

______________________________
*Chad Neeper*
Senior Systems Engineer

*Level 9 Networks*
740-548-8070 (voice)
866-214-6607 (fax)

*Full IT/Computer consulting services -- Specialized in public libraries*


On Tue, Jun 27, 2023 at 11:57 AM Phil Shirley via OPLINTECH <
oplintech at lists.oplin.org> wrote:

> Hi,
>
>
>
> Something on our local network (or some software on our PCs?) is giving us
> problems. Any idea where I should look?
>
>
>
> We continue to have occasional problems with “JAR file not found” when
> starting the SDA (Sierra staff client) – this is apparently a problem on
> our network, possibly related to the large number of connections the SDA
> makes at startup to check each of its 80 or so JAR files against the
> version on the server (this might look a little like a DDoS). But today
> something different happened.
>
>
>
> We had a different problem this morning with SDA. Existing connections to
> the server continued to work (one person logged onto Sierra a few minutes
> before), and we could telnet to the port that this program uses and use the
> classic catalog and Encore, but from about 9:00 to about 9:45 when we tried
> to start the SDA, it closed after a few seconds and gave no error message.
> This happened on at least four different workstations. I think that one
> workstation was able to connect during this time. After about 9:45 I
> haven’t been able to get the problem to happen again.
>
>
>
> Any idea what might cause this? DNS was working. The person at III support
> didn’t see anything wrong. He advised me to delete the contents of the
> jarcache folder and then try loading SDA; it did not populate that folder
> at all, which is the first thing that happens when SDA connects to the
> server.
>
>
>
> I’m waiting for a call back from our firewall vendor to see if they can
> see anything on our firewall.
>
>
>
> I checked the switches that the staff use and found that the DDOS
> protection feature is disabled.
>
>
>
> Phil
>
>
>
>
>
> *Phil Shirley*
> *IT Manager*
> *Cuyahoga Falls Library*
> p. 330.928.2117 x109 e. pshirley at fallslibrary.org
> *www. fallslibrary.org <http://fallslibrary.org> a. 2015 Third Street,
> Cuyahoga Falls, OH 44221*
>
> <https://www.facebook.com/fallslibrary/>
> <https://twitter.com/FallsLibrary>
> <https://www.instagram.com/fallslibrary/>
>
>
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