Re: Ok to let all ICMP traffic through firewall?

From: Art (null_at_zilch.com)
Date: 09/23/05 

Date: Fri, 23 Sep 2005 18:26:33 GMT

On Fri, 23 Sep 2005 17:36:47 GMT, Leythos <void@nowhere.lan> wrote:

>> but what if an ISP or non ISP telephone computer tech is diagnosing a
>> non technical home user. The user doesn't have the ability to block
>> ICMP on only certain hosts. The homse user isn't running any services
>> either(may be behind a NAT device). Ping is ideal in this instance.
>> what other option is there to see that he is online,. as a first step
>> in diagnosing the problem?
>
>Sorry, that's not a good reason. The ISP can see if the modem is on-
>line, and the ISP can see if there is a connection between the modem and
>the NAT device or PC at the hardware level. You don't have to allow ping
>for any testing/reason, there are always ways around it.

I'm curious .... how does the ISP know?

In that vein, I noticed Sygate alerting on the kernel (I think it was)
calling out. Using the traffic log I found that the attempts were to
my ISP. Blocking the attempts has no effect on my internet activity,
as near as I can tell. I wonder what the purpose of this attempted
outbound might be. I don't use any software supplied by my ISP, so
it's not spyware (which some ISPs do use).

Art
  
http://home.epix.net/~artnpeg

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