- usually these are running with very few dependencies in the userspace stack, such as a getty directly spawned by init (or the modern equivalent arrangement). This means that it's accessible even if your networking stack is not working, or if you screw up your firewall config. You can even make sure your init / getty / bash are statically linked so that not even ld.so breakage will stop you.
- it looks like they're also enabling Linux's Magic SysRq features, which gives you some very raw hooks into the kernel itself.
- usually these are running with very few dependencies in the userspace stack, such as a getty directly spawned by init (or the modern equivalent arrangement). This means that it's accessible even if your networking stack is not working, or if you screw up your firewall config. You can even make sure your init / getty / bash are statically linked so that not even ld.so breakage will stop you.
- it looks like they're also enabling Linux's Magic SysRq features, which gives you some very raw hooks into the kernel itself.