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), […]
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 […]
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 […]
SMART is a monitoring system, included in most modern hard disks, that attempts to diagnose disk health and predict impending drive failure. The smartctl/smartd utility of smartmontools is the standard for Linux/Unix and versions of it are available for Windows as well. DiskCheckup also seems to be a good utility for Windows. Many modern controller […]
Some quick setup notes for Debian 8 (“Lennie”). Add yourself to the sudoers group: Set up unattended security updates: (Select ‘yes’ to the ‘Automatically download’ question.) Install all tools for dev/package builds: (Alternatively, installing build-essentials will give you all standard c/c++/make/dpkg libraries, although not the kernel headers.) “Permission denied” CD-ROM error: Optical drives and network […]
The purpose of this page is to list some tools for SATA disk or device troubleshooting on Unix-like operating systems. Serial ATA is specified by the SATA International Organization; the most current revision as of October 2015 is SATA 3.2, released August 2013. Intel specifies the Advanced Host Controller Interface; as of October 2015 the […]
This is a summary of standard and nested RAID levels that I might implement either in a small home/office environment or from enterprise vendors. I’m avoiding the rarely-seen levels like 2, 3, and 4 as well as vendor-specific “RAID” implementations like RAID-S or X-RAID. Fortunately, many major vendors like Dell, Supermicro, and Silicon Mechanics are […]
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 […]
sed and awk are two powerful but often overlooked data processing tools, and if you know how to use them effectively you’ll be well ahead of many sysadmins and developers. sed sed is an in-place stream editor, that is, it accepts input from a file or STDIN, manipulates the data stream in some way, and […]
grep is a useful utility that finds fixed strings or patterns of text in a given file or standard input. Used in conjunction with error logs or debugger output, grep can help a programmer identify errors in an application code base or filesystem; to help with this, grep understands regular expressions, what it calls “extended” […]