traceroute problems

[Wojciech Puchar]

> to prevent you from learning about their routing paths.  In these cases,
> you get back the "1 * * *" type of output from traceroute.  Also, by
> default traceroute attempts to do a reverse DNS on the IP address, so
> you can speed things up by doing a 'traceroute -n' to avoid this look-up.
>
many commercial firewalls, including those in integrated devices, tend to 
block everything excluding often used services. some even block ICMP ping.