# Set some basic hardening options for all connections
Host *
- # Disable undocumented roaming feature as it is known to be vulnerable
- UseRoaming no
+ # Disable undocumented roaming feature as it is known to be vulnerable
+ UseRoaming no
- # Only use secure crypto algorithms
- KexAlgorithms mlkem768x25519-sha256,sntrup761x25519-sha512,sntrup761x25519-sha512@openssh.com,curve25519-sha256,curve25519-sha256@libssh.org,diffie-hellman-group-exchange-sha256
- Ciphers aes256-gcm@openssh.com,aes128-gcm@openssh.com,chacha20-poly1305@openssh.com,aes256-ctr,aes192-ctr,aes128-ctr
- 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
+ # Only use secure crypto algorithms
+ KexAlgorithms mlkem768x25519-sha256,sntrup761x25519-sha512,sntrup761x25519-sha512@openssh.com,curve25519-sha256,curve25519-sha256@libssh.org,diffie-hellman-group-exchange-sha256
+ Ciphers aes256-gcm@openssh.com,aes128-gcm@openssh.com,chacha20-poly1305@openssh.com,aes256-ctr,aes192-ctr,aes128-ctr
+ 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
- # Always visualise server host keys (helps to identify key based MITM attacks)
- VisualHostKey yes
+ # Always visualise server host keys (helps to identify key based MITM attacks)
+ VisualHostKey yes
- # Use SSHFP (might work on some up-to-date networks) to look up host keys
- VerifyHostKeyDNS yes
+ # Use SSHFP (might work on some up-to-date networks) to look up host keys
+ VerifyHostKeyDNS yes
- # Send SSH-based keep alive messages to connected server to avoid broken connections
- ServerAliveInterval 10
- ServerAliveCountMax 30
+ # Send SSH-based keep alive messages to connected server to avoid broken connections
+ ServerAliveInterval 10
+ ServerAliveCountMax 30
# Disable TCP keep alive messages since they can be spoofed and we have SSH-based
# keep alive messages enabled; there is no need to do things twice here
TCPKeepAlive no
- # Ensure only allowed authentication methods are used
- PreferredAuthentications publickey,keyboard-interactive,password
+ # Ensure only allowed authentication methods are used
+ PreferredAuthentications publickey,keyboard-interactive,password
# Prevent information leak by hashing ~/.ssh/known_hosts
HashKnownHosts yes