Are ICMP packets important?

[Alex Snow]

my isp blocked icmp packets 'because they use up bandwidth' but only 
on their subnet. I can ping whoever I want and get a reply if they're 
outside the subnet.
On Wed, Feb 11, 2004 at 01:58:59PM -0500, Chuck 
Hallenbeck wrote:
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> Hi gang,
> 
> Now that I have a cable modem connection, I have implemented a
> firewall and have been tinkering with it. I have been unable to
> ping any hosts on the net, and have disected my firewall up one
> side and down the other looking for the problem. Ping uses ICMP
> packets.
> 
> Finally, out of either desperation or inspiration, not sure
> which, I called my ISP and mentioned that I am unable to ping
> anyone on other systems. He said that they have "disabled ICMP
> packets" due to security concerns. Since ping is the only thing I
> know about that uses ICMP, I decided I would not press the point
> until something else came along.
> 
> Does anyone know what else I ought to be on the lookout for?
> 
> What about audio streams that persist over long periods of time?
> I occasionally lose a connection to a realaudio stream with the
> message "the server has timed out", and this seems sometimes to
> happen right in the middle of playing something, not after a
> lengthy silence. No more silences with cable modem. Is it
> possible that a remote host might be trying to ping me to see if
> I am alive, and my inability to send or receive ICMP packets
> makes me appear absent?
> 
> If anyone has any light to shed on this issue of what trouble I
> might expect with my ICMP packets blocked, I would appreciate
> hearing about it.
> 
> Thanks,
> Chuck
> 
> 
> - -- 
> The Moon is Waning Gibbous (70% of Full)
> In a world without Fences or Walls no one needs Windows or Gates.
> My home page is now at http://www.mhcable.com/~chuckh
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