Chap6 Kernel Services and Configuration

Question 1

To see what command line a system was booted with type:

Answer 1

$ cat /proc/cmdline
BOOT_IMAGE=/boot/vmlinuz-4.4.0-75-generic.efi.signed root=UUID=76da709a-25f0-4cc3-b8a2-3216b766ca11 ro quiet splash vt.handoff=7
which is found in /boot/grub/grub.cfg

Question 2

sysctl -a

Answer 2

Display current values of sysctl

Question 3

Location of the sysctl config file, to make changes that are fixed at boot.

Answer 3

/etc/sysctl.conf

Question 4

sysctl -p

Answer 4

Effectuates immediate digestion of whatever is in /etc/sysctl.conf

Question 5

Block icmp with sysctl

Answer 5

$ sudo sysctl net.ipv4.icmp_echo_ignore_all=1

Question 6

sysctl

Answer 6

configure kernel parameters at runtime

Question 7

Where are sysctl values stored?

Answer 7

/proc/sys