Among the most useful tools for a network engineer's toolbox are those that combine ping, DNS lookup, and traceroute capabilities. This section introduces three of them (mtr, PingPlotter, and VisualRoute).
mtr is a command-line tool for real-time path surveillance and statistics. PingPlotter and VisualRoute are commercial graphical tools available as trial downloads that add a great deal of statistics and correlation analysis to the ping and traceroute tools and allow probing over an extended period of time. Figures 6-9 through 6-11 provide example screenshots of these tools. VisualRoute is a product of Visualware Inc. (http://www.visualware.com), and PingPlotter is a product of Nessoft, LLC (http://www.nessoft.com).
Just a reminder when filtering IP traffic: The UNIX traceroute implementations use Internet Control Message Protocol (ICMP) and User Datagram Protocol (UDP), whereas the Windows implementation relies solely on ICMP. However, some UNIX traceroutes can be forced to use ICMP probe packets as well.
UNIX gateways are capable of resembling what is referred to as an extended ping in the Cisco world. This can be accomplished with the command-line switch ping -I [ifaddr] on OpenBSD and Linux, and ping -S [ifaddr] on FreeBSD. There is also an equivalent for an extended trace on UNIX. This is done via the traceroute -s [ifaddr] command sequence on OpenBSD and FreeBSD. Both the ping and traceroute commands under UNIX have interesting and nontrivial features. Look at the man pages for further details.
If you require pings or traces from distant sources, you can find a variety of looking glasses and Domain Name System (DNS)/whois front ends all over the Internet (http://www.traceroute.org). You will read more about this in Chapter 10, "ISP Connectivity with BGPv4: An Exterior Gateway Path-Vector Routing Protocol for Interdomain Routing." Figure 6-12 shows an example looking-glass web interface of the Vienna Internet exchange (VIX), a public noncommercial peering point in Austria (http://www.vix.at).