BSD

TCP congestion control

sysctl net.inet.tcp.cc
net.inet.tcp.cc.available: newreno
net.inet.tcp.cc.algorithm: newreno
kldload cccubic
kldload ccvegas
kldload cccdg

relayd

https://man.openbsd.org/relayd.conf.5 layer 3 and/or layer 7 load-balancer, application layer gateway, or transparent proxy

PF

https://man.openbsd.org/pf.conf

pass in all
pass in from any to any
pass in proto tcp from any port < 1024 to any
pass in proto tcp from any to any port 25
pass in proto tcp from 10.0.0.0/8 port >= 1024 \
to ! 10.1.2.3 port != ssh
pass in proto tcp from any os "OpenBSD"
pass in proto tcp from route "DTAG"

ipfw

sudo ipfw add fwd 127.0.0.1,12345 tcp from not me to any 80 in via en1
sudo ipfw add fwd 127.0.0.1,12345 tcp from not me to any 443 in via en1

ZFS

https://www.freebsd.org/cgi/man.cgi?query=zpool

zpool create pool_name da0p3 da1p3
zpool create pool_name \
mirror da0 da1 \
mirror da2 da3 \
log mirror da4 da5
zpool add pool cache da2 da3
zpool list
zpool get all pool_name
zpool status pool_name
zpool iostat -v pool_name 5
zpool list -v pool_name

DTrace

https://wiki.freebsd.org/DTrace/Tutorial

CAM Target Layer(ctl)

The ctl subsystem provides SCSI target devices emulation

HA cluster

https://bsdmag.org/nearly-online-zpool-switching-two-freebsd-machines/