[SOLVED] - Buffer full ? Timeout on TCP connections ? Something slow down my OPN

[romain]

I have a strange bug and I don't know where to look.

The symptom are very clear but I don't know how to reproduce it.

After some time / traffic (I don't know what is the source of the trouble yet), our service seems to go down (email exchange, netscaler access gateway to connect remotely to our desktop). The endpoint lost connection for few seconds.

The strange thing is that the PING is good and stable. I can access to the firewall through SSH or web but it seems to be very slow. For example, the history of the command take few seconds to display. I don't timeout but it's slow for few seconds / minutes.

It seems that some buffer is getting full and empty itself after few seconds (10/20). During this time, the ping is okay, the SSH session is very slow and on some service like RDP, we loose our connection.

I test the connection directly by using the VPN without going through our netscaler and same results.

I also check the health of the firewall and there is nothing. The CPUs and the RAM are fine. The number of sessions is okay (around 1300/2500 max). No error nowhere.

I don't have particular error on the interface level. I let the default MTU and MSS but I have any error which can tell me to change these seetings.

I try to look into Sync ACK but I didn't see anything particular. There is some but nothing more when the timeout / struggle time is on.

The datacenter provider don't see anything on it side. I test from different localisation and endpoint and always get these results.

Do you have any idea in which direction I can have a look ? 

Thank you
Romain

[romain]

I saw some other post dealing with some possible similar issu but I'm not sure this is the same trouble :

https://forum.opnsense.org/index.php?topic=592.msg1931

https://forum.opnsense.org/index.php?topic=289.15

[romain]

I found the trouble. It was on the datacenter's infrastructure. Thank you

[franco]

Thanks for clearing that up, marking it solved.