What protocols does traceroute use?
A traceroute works by sending Internet Control Message Protocol (ICMP) packets, and every router involved in transferring the data gets these packets. The ICMP packets provide information about whether the routers used in the transmission are able to effectively transfer the data.
Can you disable Traceroute?
Traceroute succeeds because of UDP transmission. You cannot block ICMP out bound either because the ICMP message will be coming from the router itself. So you can use CoPP to block ICMP messages originating from the router and still block traceroute. traceroute relies on both UDP and ICMP to work effectively.
Should I block Traceroute?
The traceroute tool will display routes and trip times on an IP network. Since blocking these UDP ports alone will not block traceroute capabilities without also blocking potentially legitimate traffic on a network, it is unnecessary to block them explicitly.
What is the ICMP port?
ICMP has no ports and is neither TCP nor UDP. ICMP is IP protocol 1 (see RFC792), TCP is IP protocol 6 (described in RFC793) and UDP is IP protocol 17(see RFC768). UDP and TCP have ports, ICMP has no ports, but types and codes. If you really want to filter ICMP.
How to make traceroutes work with a firewall?
Once you’ve enabled these types of packets for incoming traffic in your firewall (s), you’ll see that your traceroute will now function as it should. If your firewall does not allow you to configure accepting specific types of ICMP packets, try allowing incoming ICMP packets altogether (if that’s not too much of a compromise for you).
How to use traceroute from both Windows and Unix?
If you have a firewall and if you want traceroute to work from both machines (Unix/Linux and Windows) you will need to allow both protocols inbound through your firewall (UDP with ports from 33434 to 33534 and ICMP type 8).” NOTE: Traceroute (tracert) from Windows does not use UDP; it uses ICMP over IP by default.
What kind of packets are used in traceroute?
Traceroute is using ICMP packets (plus UDP on Linux systems, but that’s outside the scope of this blog entry. You can read more about it on the page I linked above). But even for an outgoing traceroute you need to accept incoming ICMP packets.
Is there a liability of using UDP traceroute on the Internet?
“There is a liability of using UDP traceroute on the Internet. Many screening routers, firewalls, and even hosts will silently drop UDP packets, effectively destroying the usability of traceroute. On internal networks, or networks known to have no firewalls, conventional traceroute can continue to provide diagnostic value.