Use netcat instead of telnet
Network engineers often use telnet to establish a connection to a service on a remote server. Apple dropped the telnet and ftp client in macOS High Sierra. First I was…
Authenticate sudo with TouchID on a MacBook Pro
If you own a Mac equipped with a touch bar and you use the command line and sudo often, you can enable the TouchID of your Mac to authenticate yourself.…
Hide your version of BIND
To hide your version of bind, enter the following value to your named.conf version "[NONE]"; in the option section: options { directory "/var/lib/bind"; version "[NONE]"; }; Check the value with…
Subnet Masks
A subnetwork, or subnet, is a logically visible, distinctly addressed part of a single Internet Protocol network. The process of subnetting is the division of a computer network into groups of computers that have a common,…
SI prefixes
An SI ⇒prefix is a name that precedes a basic unit of measure to indicate a ⇒decimal ⇒multiple or ⇒fraction of the unit. Each prefix has a unique symbol that is prepended to…
pcap filter
tcpdump and ngrep are both based on libpcap. Therefore both use the same filter expressions. Here is the manual page of the ⇒pcap filter expression. These filter expressions are also…