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