===== Overview =====

Breakdown of ''systemd-sysctl''.

External links:

  * [[http://man7.org/linux/man-pages/man8/systemd-sysctl.8.html|man page]]
  * [[https://www.freedesktop.org/software/systemd/man/sysctl.d.html|FreeDesktop page]]

===== File list =====

  * ''/etc/''
    * ''sysctl.conf'' [empty]
    * ''sysctl.d/''
      * ''99-sysctl.conf'' [link to above so empty]
  * ''/usr/lib/''
    * ''systemd/''
      * ''systemd-sysctl''
      * ''system/''
        * ''systemd-sysctl.service''
        * ''sysinit.target.wants/''
          * ''systemd-sysctl.service''
    * ''sysctl.d/''
      * ''10-default-yama-scope.conf''
      * ''20-pptpd.conf''
      * ''50-coredump.conf''
      * ''50-default.conf''
      * ''50-libkcapi-optmem_max.conf''
      * ''60-libvirtd.conf''

===== Config files =====

==== 10-default-yama-scope.conf ====

<code>
kernel.yama.ptrace_scope = 0
</code>

==== 20-pptpd.conf ====

<code>
net.ipv4.ip_forward = 1
</code>

==== 50-coredump.conf ====

<code>
kernel.core_pattern=|/usr/lib/systemd/systemd-coredump %P %u %g %s %t %c %h %e
</code>

==== 50-default.conf ====

<code>
# Use kernel.sysrq = 1 to allow all keys.
# See https://www.kernel.org/doc/html/latest/admin-guide/sysrq.html for a list
# of values and keys.
kernel.sysrq = 16

# Append the PID to the core filename
kernel.core_uses_pid = 1

# Source route verification
net.ipv4.conf.all.rp_filter = 1

# Do not accept source routing
net.ipv4.conf.all.accept_source_route = 0

# Promote secondary addresses when the primary address is removed
net.ipv4.conf.all.promote_secondaries = 1

# Fair Queue CoDel packet scheduler to fight bufferbloat
net.core.default_qdisc = fq_codel

# Enable hard and soft link protection
fs.protected_hardlinks = 1
fs.protected_symlinks = 1
</code>

==== 50-libkcapi-optmem_max.conf ====

<code>
net.core.optmem_max = 81920
</code>

==== 60-libvirtd.conf ====

<code>
fs.aio-max-nr = 1048576
</code>