testing: Move sysctl settings to sysctl.d and add some memory settings

Debian trixie doesn't provide a 99-sysctl.conf symlink in that directory
anymore.  The memory settings are also useful there as the default of
one changed and overbooking helps when forking a process with large
memory footprint (e.g. the IKE daemon).

testing/hosts/default/etc/sysctl.conf

@@ -1,62 +0,0 @@
-#
-# /etc/sysctl.conf - Configuration file for setting system variables
-# See /etc/sysctl.d/ for additional system variables
-# See sysctl.conf (5) for information.
-#
-
-#kernel.domainname = example.com
-
-# Uncomment the following to stop low-level messages on console
-#kernel.printk = 3 4 1 3
-
-##############################################################3
-# Functions previously found in netbase
-#
-
-# Uncomment the next two lines to enable Spoof protection (reverse-path filter)
-# Turn on Source Address Verification in all interfaces to
-# prevent some spoofing attacks
-#net.ipv4.conf.default.rp_filter=1
-#net.ipv4.conf.all.rp_filter=1
-
-# Uncomment the next line to enable TCP/IP SYN cookies
-# See http://lwn.net/Articles/277146/
-# Note: This may impact IPv6 TCP sessions too
-#net.ipv4.tcp_syncookies=1
-
-# Uncomment the next line to enable packet forwarding for IPv4
-net.ipv4.ip_forward=1
-
-# Uncomment the next line to enable packet forwarding for IPv6
-#  Enabling this option disables Stateless Address Autoconfiguration
-#  based on Router Advertisements for this host
-net.ipv6.conf.all.forwarding=1
-
-
-###################################################################
-# Additional settings - these settings can improve the network
-# security of the host and prevent against some network attacks
-# including spoofing attacks and man in the middle attacks through
-# redirection. Some network environments, however, require that these
-# settings are disabled so review and enable them as needed.
-#
-# Do not accept ICMP redirects (prevent MITM attacks)
-#net.ipv4.conf.all.accept_redirects = 0
-#net.ipv6.conf.all.accept_redirects = 0
-# _or_
-# Accept ICMP redirects only for gateways listed in our default
-# gateway list (enabled by default)
-# net.ipv4.conf.all.secure_redirects = 1
-#
-# Do not send ICMP redirects (we are not a router)
-#net.ipv4.conf.all.send_redirects = 0
-#
-# Do not accept IP source route packets (we are not a router)
-#net.ipv4.conf.all.accept_source_route = 0
-#net.ipv6.conf.all.accept_source_route = 0
-#
-# Log Martian Packets
-#net.ipv4.conf.all.log_martians = 1
-
-# Enable coredump for suid binaries
-fs.suid_dumpable = 1

testing/hosts/default/etc/sysctl.d/99-strongswan.conf

@@ -0,0 +1,16 @@
+# Enable packet forwarding for IPv4
+net.ipv4.ip_forward=1
+
+# Enable packet forwarding for IPv6
+#  Enabling this option disables Stateless Address Autoconfiguration
+#  based on Router Advertisements for this host
+net.ipv6.conf.all.forwarding=1
+
+# Enable coredump for suid binaries
+fs.suid_dumpable = 1
+
+# As we run with very little memory, use the old default to reduce overhead
+vm.max_map_count = 65530
+
+# Allow overcommitting, in particular for forks
+vm.overcommit_memory = 1