nmap

nmap is a security scanner capable of mapping topology, discovering hosts, determining OS and device profiles, examining individual services, and exposing vulnerabilities across networks. It’s licensed under the GPL and binaries are available for most platforms. A graphical frontend called Zenmap is available in most Linux repos. More specifically, nmap sends ICMP Echo (type 0), […]

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mtr

mtr combines the behavior of the ping and traceroute utilities: it traces a route path between localhost and a destination device or computer, showing you a list of the routers between them as well as the average round-trip times and packet loss to each router. To do this mtr utilizes ICMP Type 0 and 11 […]

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wget and cURL

wget wget is a GNU utility for retrieving files over the web using the popular internet transfer protocols (HTTP, HTTPS, FTP). It’s useful either for obtaining individual files or mirroring entire web sites, as it can convert absolute links in downloaded documents to relative links. The GNU wget manual is the definitive resource. Some Useful […]

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tcpdump

tcpdump is a useful packet analyzer distributed under the BSD license. It is included with most Linux and Unix distros, and it’s available for Windows using the Winpcap library. As you might imagine, tcpdump is excellent at troubleshooting problematic connections to remote systems where the cause is otherwise unclear. This is particularly useful for getting […]

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