Ljubomir Ljubojevic wrote:
ICMP packets are blocked by Billion, it's 99% chance, since public IP resides on the Billion. Only way (known to me) to pass ICMP to your CentOS server (on cheap modem/routers) is to do 1:1 NAT (all connections to all ports are redirected to system behind it with set IP).
If you need to be able to ping CemtOS system and not Billion, then you should set modem to bridge mode and pass public IP to CentOS. But caveat is that this would mean that if you turn on CentOS firewall or set it improperly you would be wide open, and that you will not be able to willfully bypass CentOS server (if he is down) and just plug PC's to modem directly.
Thanks for the response. I don't really mind if external sites cannot ping the machine; I was just a little surprised at this, particularly as I didn't see anything about it in the documentation.
I'll try asking on the Billion site.