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Server Session Termination Errors Metric

wperez
Inactive

Good morning,

DMI Definition :"The number of Server Session Termination errors. This category of errors applies whenthe server detects an error on the software service level and closes the TCP session witha RESET packet".

 

Someone has idea about which are the possible causes of this error, and which analyzers are related with it?

Regards

6 REPLIES 6

adam_litwin
Dynatrace Participant
Dynatrace Participant

You might see those metric for all analyzers. When application server (operating system) detect the problem with application it sends RST packet. In most cases it means that listening port is blocked/closed.

Could this application server behavior be associated with a HTTP 500 error code?!

 

Not that I can imagine. Typically the "Error 500" is communicated back to the client and shouldn't cause a reset.

matthew_eisengr
Inactive

I have an additional question to how these are counted. I have a situation where although 'Server Session Termination' is a TCP error, it doesn't appear to be counted in the more general 'TCP errors' category. Is this by design or do I have a bug on my hands?

Running CAS on 12.2.2.99

jean_louis_lorm
Dynatrace Pro
Dynatrace Pro

Hello,

I have found this explanation in this documentation :

https://answers.dynatrace.com/attachments/12134217...

Server is unexpectedly terminating a connection that was successfully opened. The server sends a RESET packet to the Client.
Such error roots at application using TCP session that is monitored. It does not necessarily mean application failure; usually it means that the application encountered a condition in which it decided to immediately terminate session with the client (for instance, because of an application security policy violation by the client).

I hope, it's help you.

Regards,

JLL

ulf_thornander3
Inactive

Strictly speaking it's not following the old TCP standard to do like this, but on the other hand most HTTP system today do this to save time&resources.

https://ask.wireshark.org/questions/13986/why-tcp-reset-sent-after-receive-finack-packet

https://social.technet.microsoft.com/Forums/en-US/a436ac6f-a11e-49aa-a2bb-a165f0bbb1cd/server-2008-r...

Mind you though- there should be a proportion to the value so that if it starts to rise without the total number of session increasing, you potentially have a resource problem in the server.