[63203] in North American Network Operators' Group
Re: ICMP Blocking Woes
daemon@ATHENA.MIT.EDU (Anthony Cennami)
Tue Sep 30 08:30:11 2003
Date: Tue, 30 Sep 2003 08:31:28 -0400
From: Anthony Cennami <narziss@cdardn.net>
To: Eric Kagan <ekagan@axsne.com>
Cc: nanog@merit.edu
In-Reply-To: <00ed01c38742$fdc89c40$6464a8c0@EDKP3W2K>
Errors-To: owner-nanog-outgoing@merit.edu
They are filtering either ICMP echo or echo reply; using an LBNL/Unix
traceroute is successful the entire path.
Eric Kagan wrote:
>>WindowsNT tracert.exe uses 92 byte icmp packets. There is a modified
>
> version
>
>>that uses a smaller sized icmp packet at
>>http://www.nthelp.com/NT6/tracert_broken.htm that works fine on Windows
>>2000.
>
>
> So if tracert1 doesn't work, would that mean Comcast is actually blocking
> all ICMP ? I have been told they are only blocking 135-139, 4444
> I get the same results with tracert and tracert1 (below)
>
> D:\Temp>ver
>
> Microsoft Windows 2000 [Version 5.00.2195]
>
> D:\Temp>tracert1 www.advil.com
>
> Tracing route to www.advil.com [164.109.5.98] over a maximum of 30 hops:
>
> 1 20 ms 10 ms 10 ms c-24-218-168-1.ne.client2.attbi.com
> [24.218.168.1]
> 2 20 ms 10 ms 10 ms 24.62.0.245
> 3 * * * Request timed out.
> 4 * * * Request timed out.
> 5 * * * Request timed out.
> 6 * * * Request timed out.
> 7 * * * Request timed out.
>
> D:\Temp>tracert www.advil.com
>
> Tracing route to www.advil.com [164.109.5.98] over a maximum of 30 hops:
>
> 1 20 ms 10 ms 10 ms c-24-218-168-1.ne.client2.attbi.com
> [24.218.168.1]
> 2 10 ms 10 ms 20 ms 24.62.0.245
> 3 * * * Request timed out.
> 4 * * * Request timed out.
> 5 * * * Request timed out.
> 6 * ^C
>
>
> Eric
>
