Hello guys. I am having problems with our server. The server appears down when accessed remotely, then it goes up when you ping from another machine on its internal network. this has been recurring many times each day. My server has Redhat 9 installed (with default kernel), 768mb of ram, realtek NIC (RT8139too or something like that), and has 70gb spare disk space. I wonder why it seems to be sleeping and wakes up when another machine pings it from inside. Another problem is that the datacenter doesnt see it as their fault because other machines does not exhibit the same behavior.

I tried changing from one router ports to another, all lead to the same result. Its really funny because it functions properly (all services are ok: apache, ssh, sql), but somehow, connection dies without evidence in the logs.

Please help.

Also, how can I change ssh port from 22 to say 1034. hank you very much.

the problem is mostly like power management
disable suspend and sleep in your bios
and the port for ssh can be changed at /etc/ssh/sshd_config

Thank your for your reply. Would it be possible to change port of ssh to say 10000? I mean ssh's port assignment is 7622, 7922, 22 right? About the server, I checked bios and power management is off. Also, It does not go down from within the network. Could it have been attacked or something like that??? If so, its funny coz I had just deployed it and just hours after, that happens....

you can change your ssh to any port you want even one thats normally used by another server like telnet for easier access from some firewalls outside.
just make sure that no other application is using that port.