traceroute doesnt work

RouterOS General
1

Hi, I have mikrotik as a firewall.
All computers behind the firewall cant make traceroute, they are reaching just the first hop the mikrotik and no more.

traceroute http://www.yahoo.com

traceroute to http://www.yahoo.com (216.109.117.110), 30 hops max, 40 byte packets
1 fe1- (212.110.x.x) 0.248 ms 0.194 ms 0.168 ms (MIkrotik)
2 * * *
3 * * *
4 * * *
5 * * *
6 * * *
7 * * *

I tried to open UDP ports 33435 and 33434 , the problem remains.

any help?

thanks

2

Principle of traceroute:
The principle of any trace route program is based on the ICMP protocol. It uses the TTL field in the IP header of the packet. The main goal of the TTL field is to avoid infinite loop. By increasing the TTL by one each time the program send a packet each hops on the path are successively discovered and the time needed for a round trip is deducted.