What is traceroute?
Traceroute is a command that shows you the route over the network between two systems,showing the intermediate routers or hops.It also shows you how systems are connected to each other, letting you see how your ISP connects to the Internet.
This can happen if icmp and icmp error inspection are not enabled in the PIX Firewall.
In order to resolve this issue, configure icmp and icmp error inspection in the PIX Firewall as this example command output shows:
hostname(config-pmap-c)#inspect icmp error