Confused about ping...Robin.Laing at drdc-rddc.gc.ca

[David G. Miller (aka DaveAtFraud)]

Robin.Laing at drdc-rddc.gc.ca wrote:

> Craig White wrote:
>
>> On Thu, 2005-10-06 at 15:14 -0500, Mike McCarty wrote:
>>
>>> I had some troubles loading a web page, so I
>>> decided to try looking for connectivity.
>>> I did this:
>>>
>>> $ nslookup www.worldwideschool.org
>>> Server:         151.164.11.201
>>> Address:        151.164.11.201#53
>>>
>>> Non-authoritative answer:
>>> Name:   www.worldwideschool.org
>>> Address: 207.195.133.148
>>>
>>> $ ping 207.195.133.148
>>> PING 207.195.133.148 (207.195.133.148) 56(84) bytes of data.
>>> From 209.120.242.6 icmp_seq=0 Packet filtered
>>> From 209.120.242.6 icmp_seq=1 Packet filtered
>>> From 209.120.242.6 icmp_seq=2 Packet filtered
>>> From 209.120.242.6 icmp_seq=3 Packet filtered
>>>
>>> What does "Packet filtered" mean?
>>>
>>> Using "man ping" gave no results on this, and "info ping"
>>> shows the same thing as "man".
>>
>>
>> ----
>> Just a wild guess is that a router between you and the target is
>> preventing the icmp packets from progressing and thus, you are neither
>> getting a ping back nor a reject back from the target.
>>
>> Craig
>>
>>
>
> Give traceroute a try.  It may work better in this case.
>
> -- 
> Robin Laing
>
Alternatively, nmap can be used to determine if a system is 
up/accessible.  My ISP filters ICMP to their servers so the only way I 
can diagnose certain problems as being on my end or theirs is to use 
nmap.  I can traceroute to my own box if my ISP is up but I can't 
traceroute to their gateway since it filters ICMP.  nmap lets me see if 
their gateway is accessible.

Cheers,
Dave