i have four suse linux servers siting on different lan. they are connected by a router and it is configured to allow these machines to ping one another.
default routings have been added to all these machines. the problem is: 1) machine A can ping to machine B and D 2) machine B,C and D can ping to machine A why can't machine A ping C?
I troubleshoot by setting up machine E on the same lan as machine A, and set machine A ip address on machine E (disabled machine NIC card during this test). i was able to ping machine B,C and D on machine E.
they are not sitting behind any firewall. i have flush all ip tables for these machines. i have turned off all OS firewall.