On 20.7.2011 12:51, Timothy Murphy wrote: > Further to my question, > how can I determine if it is the Billion 5200S modem/router > that is preventing pings, or if it is the CentOS-6 MicroServer > attached to the modem/router? ... > Is there any simple way, short of using something like ethereal, > of determining if ICMP packets are reaching the computer, > and being rejected there? I would use tcpdump on the CentOS Server to be sure the icmp echo requests are arriving or not. tcpdump is something like ethereal but it could be as easy as $ tcpdump -l proto \\icmp or $ tcpdump -l proto \\icmp and host sourceip or $ tcpdump -li ethX proto \\icmp or ... -- Kind Regards, Markus Falb -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 307 bytes Desc: OpenPGP digital signature URL: <http://lists.centos.org/pipermail/centos/attachments/20110720/5c2a5913/attachment-0004.sig>