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# `man sshd_config` says "for each keyword, the first obtained value will be used". So I decided to put my configs before all others to override them all.
# Based on manpage, setting PasswordAuthentication no, and Arch Linux default KbdInteractiveAuthentication no, with other defaults seems already equivalent to AuthenticationMethods publickey, but I still put it here for redundancy.
# https://wiki.archlinux.org/title/OpenSSH#Force_public_key_authentication
AuthenticationMethods publickey
PermitRootLogin no
PasswordAuthentication no
# KbdInteractiveAuthentication no and UsePAM yes are Arch Linux default settings see /etc/ssh/sshd_config.d/00-archlinux.conf, I need these configs, I put them here just in case Arch Linux change the defaults in the future.
KbdInteractiveAuthentication no
UsePAM yes
# when ssh into this remote server, client if use alacritty need `SendEnv COLORTERM` to send the env to server, so server ls can default output color, more see comments in my alacritty.toml config
AcceptEnv COLORTERM
# https://unix.stackexchange.com/a/472848 wrote about sshd_config AllowUsers
# CIDR address: "Notice that that will not work with 'inconsistent' addresses
# (where the bits outside the mask are not all 0, eg. 192.168.177.0/22)". My
# understanding is that 177 in binary is 10110001, 32-22=10 so 192.168.177.0
# last 10 binary are 0100000000, note there's a 1 so it will not work; and
# 192.168.176.0/22 works because its last 10 binary are all 0. `man
# sshd_config` also wrote about this: "Note that the mask length provided must
# be consistent with the address - it is an error to specify a mask length that
# is too long for the address or one with bits set in this host portion of the
# address. For example, 192.0.2.0/33 and 192.0.2.0/8, respectively."; the
# second part of the comment "one with bits set in this host portion of the
# address" with the example CIDR ip 192.0.2.0/8 matched my understanding above,
# 192.0.2.0/8 has a 2 which is 10 in binary which is a bit set "in" the CIDR /8
# range, so it will not work. Just before that quote, it also gives an example
# of 192.0.2.0/24 which should work. Not tested.
#
# My test shows `AllowUsers gitolite@localhost` does not work, so I use
# 127.0.0.1 and ::1
AllowUsers gitolite@10.0.0.0/24 gitolite@127.0.0.1 gitolite@::1
# Include drop-in configurations
Include /etc/ssh/sshd_config.d/*.conf
# This is the sshd server system-wide configuration file. See
# sshd_config(5) for more information.
# This sshd was compiled with PATH=/usr/local/sbin:/usr/local/bin:/usr/bin
# The strategy used for options in the default sshd_config shipped with
# OpenSSH is to specify options with their default value where
# possible, but leave them commented. Uncommented options override the
# default value.
#Port 22
#AddressFamily any
#ListenAddress 0.0.0.0
#ListenAddress ::
#HostKey /etc/ssh/ssh_host_rsa_key
#HostKey /etc/ssh/ssh_host_ecdsa_key
#HostKey /etc/ssh/ssh_host_ed25519_key
# Ciphers and keying
#RekeyLimit default none
# Logging
#SyslogFacility AUTH
#LogLevel INFO
# Authentication:
#LoginGraceTime 2m
#PermitRootLogin prohibit-password
#StrictModes yes
#MaxAuthTries 6
#MaxSessions 10
#PubkeyAuthentication yes
# The default is to check both .ssh/authorized_keys and .ssh/authorized_keys2
# but this is overridden so installations will only check .ssh/authorized_keys
AuthorizedKeysFile .ssh/authorized_keys
#AuthorizedPrincipalsFile none
#AuthorizedKeysCommand none
#AuthorizedKeysCommandUser nobody
# For this to work you will also need host keys in /etc/ssh/ssh_known_hosts
#HostbasedAuthentication no
# Change to yes if you don't trust ~/.ssh/known_hosts for
# HostbasedAuthentication
#IgnoreUserKnownHosts no
# Don't read the user's ~/.rhosts and ~/.shosts files
#IgnoreRhosts yes
# To disable tunneled clear text passwords, change to "no" here!
#PasswordAuthentication yes
#PermitEmptyPasswords no
# Change to "no" to disable keyboard-interactive authentication. Depending on
# the system's configuration, this may involve passwords, challenge-response,
# one-time passwords or some combination of these and other methods.
#KbdInteractiveAuthentication yes
# Kerberos options
#KerberosAuthentication no
#KerberosOrLocalPasswd yes
#KerberosTicketCleanup yes
#KerberosGetAFSToken no
# GSSAPI options
#GSSAPIAuthentication no
#GSSAPICleanupCredentials yes
# Set this to 'yes' to enable PAM authentication, account processing,
# and session processing. If this is enabled, PAM authentication will
# be allowed through the KbdInteractiveAuthentication and
# PasswordAuthentication. Depending on your PAM configuration,
# PAM authentication via KbdInteractiveAuthentication may bypass
# the setting of "PermitRootLogin prohibit-password".
# If you just want the PAM account and session checks to run without
# PAM authentication, then enable this but set PasswordAuthentication
# and KbdInteractiveAuthentication to 'no'.
#UsePAM no
#AllowAgentForwarding yes
#AllowTcpForwarding yes
#GatewayPorts no
#X11Forwarding no
#X11DisplayOffset 10
#X11UseLocalhost yes
#PermitTTY yes
#PrintMotd yes
#PrintLastLog yes
#TCPKeepAlive yes
#PermitUserEnvironment no
#Compression delayed
#ClientAliveInterval 0
#ClientAliveCountMax 3
#UseDNS no
#PidFile /run/sshd.pid
#MaxStartups 10:30:100
#PermitTunnel no
#ChrootDirectory none
#VersionAddendum none
# no default banner path
#Banner none
# override default of no subsystems
Subsystem sftp /usr/lib/ssh/sftp-server
# Example of overriding settings on a per-user basis
#Match User anoncvs
# X11Forwarding no
# AllowTcpForwarding no
# PermitTTY no
# ForceCommand cvs server
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