config/ssh/sshd_config

   1 # OpenSSH server configuration file for IPFire
   2 #
   3 # The full documentation is available at: https://man.openbsd.org/sshd_config
   4 #
   5
   6 # Only allow version 2 of SSH protocol
   7 Protocol 2
   8
   9 # Listen on port 22 by default
  10 Port 22
  11
  12 # Listen on every interface and IPv4 only
  13 AddressFamily inet
  14 ListenAddress 0.0.0.0
  15
  16 # Limit authentication timeout to 30 seconds
  17 LoginGraceTime 30s
  18
  19 # Limit maximum instanctes to prevent DoS
  20 MaxStartups 5
  21
  22 # Only allow safe crypto algorithms
  23 KexAlgorithms sntrup761x25519-sha512@openssh.com,curve25519-sha256,curve25519-sha256@libssh.org,diffie-hellman-group-exchange-sha256
  24 Ciphers chacha20-poly1305@openssh.com,aes256-gcm@openssh.com,aes128-gcm@openssh.com,aes256-ctr,aes192-ctr,aes128-ctr
  25 MACs hmac-sha2-512-etm@openssh.com,hmac-sha2-256-etm@openssh.com,umac-128-etm@openssh.com,hmac-sha2-512,hmac-sha2-256,umac-128@openssh.com
  26
  27 # Only allow cryptographically safe SSH host keys (adjust paths if needed)
  28 HostKey /etc/ssh/ssh_host_ed25519_key
  29 HostKey /etc/ssh/ssh_host_ecdsa_key
  30 HostKey /etc/ssh/ssh_host_rsa_key
  31
  32 # Only allow login via public key by default
  33 PubkeyAuthentication yes
  34 PasswordAuthentication no
  35 ChallengeResponseAuthentication no
  36
  37 # Permit root login as there is no other user in IPFire 2.x
  38 PermitRootLogin yes
  39
  40 # Ignore user ~/.ssh/known_hosts file
  41 IgnoreUserKnownHosts yes
  42
  43 # Do not allow any kind of forwarding (provides only low security);
  44 # some of them might need to be re-enabled if SSH server is a jump platform
  45 AllowTcpForwarding no
  46 AllowAgentForwarding no
  47 PermitOpen none
  48
  49 # Send SSH-based keep alive messages to connected clients to avoid broken connections
  50 ClientAliveInterval 10
  51 ClientAliveCountMax 30
  52
  53 # Since TCP keep alive messages can be spoofed and we have the SSH-based already,
  54 # there is no need for this to be enabled as well
  55 TCPKeepAlive no
  56
  57 # Add support for SFTP
  58 Subsystem       sftp    /usr/lib/openssh/sftp-server
  59
  60 # EOF