I'm using Google Cloud, there are 2 machines on the cloud which can't ping each other, A can't ping B, and B can't ping A too; all other machines can ping to A&B as usual. But it happens only on Internet IPs, not LAN IPs.*
The difference is this way:
#fails, timeout ping 35.197.x.x #internet ips #ok as normal ping 10.240.x.x #LAN ips on google cloud
I have disabled Google Cloud firewall, firewalld service, iptables, ufw; still no luck. Why is it so?
When running 'netstat -nc' on the listener server, it keeps showing SYN_RECV and never ESTABLISHED.
#test ssh connection from A to B, #run netstat on B: netstat -nc | grep IP_OF_A