When i am unable to connect to one particular destination computer using ssh,curl,ping and its IP is not blocked in the iptables nor /etc/hosts.deny on CentOS 7, how do you discover if the block is remote or local and if local, do you have ideas on where it can be blocked (consider i tried various connection ways as mentioned above).

That remote computer works and is connectable from different IPs. Remote computer admin claims (he may be wrong) my IP is not blocked.

I would use tcpdump to see exactly which packets arrive at that computer.

For example:
where 1.2.3.4 is the IP address from which you fail to connect to the computer in question, and ens3f0 is the interface (if you omit the interface, tcpdump will use the first real NIC; you can also use -i any).

The host 1.2.3.4 expression is a filter that only collects packets to or from that host. You can also filter by protocol, port and other criteria, and use boolean logic to combine several criteria.

See the manual pages for tcpdump and pcap-filter.

1 members found this post helpful.

You should be familiar with tcpdump, considering you've been using it for years, and also have been handed it again in another thread recently:
https://www.linuxquestions.org/quest...ow-4175667621/

...where you never followed up or answered questions. And you, AGAIN, don't provide details here either; it could be blocked on a firewall, load balancer, or at the ISP connection point. You tell us nothing about anything in the environment, and we aren't going to guess. But common sense should tell you that if you can connect from OTHER addresses but not ONE particular address, that the address in question is being denied. You mention a 'remote computer admin', but again don't tell us who they work for, why you doubt them, or what you see in the logs on either side...again, do you expect us to guess?