[CentOS] 2 questions on CentOS firewall

Wed Jul 20 12:40:36 UTC 2011
Markus Falb <markus.falb at fasel.at>

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

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