I learn Linux and networking more than 10 years ago. And now that I need to configure network again for my job, I find out that most of the command lines tools I used to know do not work anymore / are deprecated. I am talking about all commands of net-tools package.
I just wanted to know why are they deprecated ? Is this because developers stop maintaining it ? And more importantly if I keep using it (old habits) could this cause security issue ?
net-tools is deprecated because it became outdated, a long time ago (its last release was in 2001, although distributions have been maintaining it since), and by the time people decided something needed to be done about it, a better alternative (iproute2) already existed. The 2009 “net-tools future” email gives more context.
If you keep using net-tools, it shouldn’t cause any security issues, but you will miss out on features added to the Linux kernel’s networking stack in the last twenty years which could help improve your security. Distributions still shipping net-tools also still provide security support for it, and the kernel features the tools set up are also still supported.
It’s well worth learning the replacements; the Debian wiki’s net-tools deprecation page lists them, and you’ll find many relevant questions here, such as alternative to "netstat -s".
