nix/services/openssh.nix

{ config, pkgs, ... }: {
  services.openssh = {
    enable = true;
    openFirewall = true;
    settings = {
      LogLevel = "VERBOSE"; # Used for fail2ban monitoring
      PermitRootLogin = "no";
      PasswordAuthentication = true; # Set this to false when keys are configured
    };
    banner = ''
    You are accessing a U.S. Government (USG) Information 
    System (IS) that is provided for USG-authorized use only.

    By using this IS (which includes any device attached to 
    this IS), you consent to the following conditions:
    
    - The USG routinely intercepts and monitors communications 
      on this IS for purposes including, but not limited to, 
      penetration testing, COMSEC monitoring, network operations
      and defense, personnel misconduct (PM), law enforcement (LE), 
      and counterintelligence (CI) investigations.
    
    - At any time, the USG may inspect and seize data stored on 
      this IS.
    
    - Communications using, or data stored on, this IS are not 
      private, are subject to routine monitoring, interception, 
      and search, and may be disclosed or used for any USG-authorized 
      purpose.
    
    - This IS includes security measures (e.g., authentication and 
      access controls) to protect USG interests--not for your personal 
      benefit or privacy.
    
    - Notwithstanding the above, using this IS does not constitute 
      consent to PM, LE or CI investigative searching or monitoring 
      of the content of privileged communications, or work product, 
      related to personal representation or services by attorneys, 
      psychotherapists, or clergy, and their assistants. Such communications 
      and work product are private and confidential. See User Agreement for 
      details. 
    '';
  };

  # Enable GPG Agent support:
  programs.gnupg.agent.enableSSHSupport = true;
}