I have a VPS with Ubuntu 16.0.4 installed on it. Every time I connected to it through SSH, the next times I attempted to connect would end up in time out errors along with any other kind of connection attempts (http, git, ping, port 8080).
I figured this means that the IP gets blocked. But couldn't find any signs of it on the system. Even stopped the whole "ufw" to no effect.
Eventually I referred to system logs and ran tcpdump as follows:
tcpdump -i ens3 icmp and icmp[icmptype]=icmpecho
Then tried pinging from a blocked IP, but nothing showed up. Note that I could see some regular pings from my VPS provider servers and also when I pinged from a not blocked device, it would appear.
Does this mean that the problem exists outside of the VPS I have acquired? Or is there any other place on it I could look up for possible blocking happening?
The Ubuntu installation is almost raw and no other firewall is installed on it as much as I checked except for the 'ufw'.