I have a little tricky behavior I can’t explain. I have a virtual machine running
container. Hosted on aWindows 2019` Hyper-V machine.
There’s a second virtual machine (same network but different physical server) running W2k19 and a
redis-client connecting to the
Due to bad configuration from time to time
redis overwhelms the Ubuntu machine, using too much memory, and producing thousands of
*connection timed out* exception in the
When this happens, all connections between machines stop working. If I try to connect via
ssh from the W2k19 machine to Ubuntu or using
telnet from the same machine on any port, I get a
*connection timed out*.
Like if something on the Linux machine did an auto ban of the IP address of the w2k19 machine. From any other machine I can connect via
telnet and so on.
Ufwis turned off
- We dont’t have
iptablesis configured with all ports open
But we still can’t connect. We reproduced the behavior on another machine, a second VM with
W2k19 and the same
What we found out would reestablish the connections between those machine was a restart of the
ssh service on the Ubuntu machine combined with a reboot of the
Just the single
sudo service sshd restart is not enough, and just a reboot of the
W2k19 machine is not enough. I can’t figure out what’s going on, and we cannot accept as a standard procedure in these cases to restart the
ssh service and reboot the machine.
But so far we are not being able to figure out what rule/configuration whatsoever is blocking the connections. It has to do something with the
ssh service probably, since restarting it does contribute to restore the connections, but how?
And why restarting the
ssh service (and rebooting the
W2k19 machine) is actually unblocking the connection to the
redis 6379 port?