Prerequisites¶

Before installing and configuring ZeroTrustKerberosLink, ensure your environment meets the following prerequisites. This will ensure a smooth installation process and optimal performance.

System Requirements¶

Hardware Requirements¶

Operating System Requirements¶

ZeroTrustKerberosLink supports the following operating systems:

Linux¶

• Ubuntu 20.04 LTS or later
• CentOS/RHEL 8 or later
• Debian 11 or later
• Amazon Linux 2

macOS¶

• macOS 11 (Big Sur) or later

Windows¶

• Windows Server 2019 or later
• Windows 10/11 Enterprise or Pro

Container Platforms¶

• Docker 20.10 or later
• Kubernetes 1.21 or later
• Amazon ECS/EKS
• Google GKE
• Azure AKS

Software Dependencies¶

Required Software¶

Optional Software¶

Network Requirements¶

Ports¶

Ensure the following ports are open in your network configuration:

Connectivity¶

ZeroTrustKerberosLink requires connectivity to:

1. Kerberos KDC: For authentication
2. AWS Services: For role assumption and credential issuance
3. Redis Server: For session and cache management
4. Client Networks: For serving API requests

Firewall Configuration¶

Example iptables rules for a Linux host:

# Allow inbound HTTPS
iptables -A INPUT -p tcp --dport 443 -j ACCEPT

# Allow outbound Kerberos
iptables -A OUTPUT -p tcp --dport 88 -j ACCEPT
iptables -A OUTPUT -p udp --dport 88 -j ACCEPT

# Allow outbound Redis
iptables -A OUTPUT -p tcp --dport 6379 -j ACCEPT

# Allow outbound HTTPS (for AWS API)
iptables -A OUTPUT -p tcp --dport 443 -j ACCEPT

AWS Requirements¶

IAM Permissions¶

ZeroTrustKerberosLink requires an IAM role with the following permissions:

{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Effect": "Allow",
      "Action": [
        "sts:AssumeRole"
      ],
      "Resource": "arn:aws:iam::*:role/ZeroTrustKerberos*"
    },
    {
      "Effect": "Allow",
      "Action": [
        "iam:ListRoles",
        "iam:GetRole"
      ],
      "Resource": "*"
    }
  ]
}

Cross-Account Setup¶

For cross-account access, each target account must have a role with a trust relationship to the ZeroTrustKerberosLink account:

{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Effect": "Allow",
      "Principal": {
        "AWS": "arn:aws:iam::ACCOUNT_ID:role/ZeroTrustKerberosLink"
      },
      "Action": "sts:AssumeRole",
      "Condition": {
        "StringEquals": {
          "sts:ExternalId": "EXTERNAL_ID"
        }
      }
    }
  ]
}

Kerberos Requirements¶

KDC Configuration¶

Ensure your Kerberos KDC is configured to:

1. Issue service tickets for the ZeroTrustKerberosLink service principal
2. Support renewable tickets
3. Allow forwardable tickets (if credential delegation is required)

Service Principal¶

Create a service principal for ZeroTrustKerberosLink:

# Example for MIT Kerberos
kadmin -q "addprinc -randkey HTTP/zerotrust.example.com"
kadmin -q "ktadd -k /etc/zerotrust/keytab HTTP/zerotrust.example.com"

Client Configuration¶

Ensure client machines have proper Kerberos configuration:

# Example /etc/krb5.conf
[libdefaults]
    default_realm = EXAMPLE.COM
    dns_lookup_realm = false
    dns_lookup_kdc = false
    ticket_lifetime = 24h
    renew_lifetime = 7d
    forwardable = true

[realms]
    EXAMPLE.COM = {
        kdc = kdc1.example.com
        kdc = kdc2.example.com
        admin_server = kdc1.example.com
    }

[domain_realm]
    .example.com = EXAMPLE.COM
    example.com = EXAMPLE.COM

TLS Certificate Requirements¶

ZeroTrustKerberosLink requires valid TLS certificates for secure communication. You can use:

1. Public CA Certificates: From providers like Let's Encrypt, DigiCert, etc.
2. Internal CA Certificates: From your organization's certificate authority
3. Self-Signed Certificates: For testing only, not recommended for production

Certificate Requirements¶

• Key Type: RSA (2048+ bits) or ECC (P-256 or higher)
• Signature Algorithm: SHA-256 or stronger
• Subject Alternative Names: Include all hostnames used to access the service

Redis Requirements¶

Redis Configuration¶

Redis should be configured with:

1. TLS Encryption: For secure communication
2. Authentication: Password or certificate-based
3. Persistence: To prevent data loss
4. High Availability: Redis Sentinel or Redis Cluster for production

Example secure Redis configuration:

# /etc/redis/redis.conf
port 0
tls-port 6379
tls-cert-file /etc/redis/tls/redis.crt
tls-key-file /etc/redis/tls/redis.key
tls-ca-cert-file /etc/redis/tls/ca.crt
tls-auth-clients yes
requirepass STRONG_PASSWORD
maxmemory 1gb
maxmemory-policy allkeys-lru

Security Prerequisites¶

SELinux/AppArmor¶

If using SELinux or AppArmor, ensure proper profiles are configured:

# Example SELinux policy for ZeroTrustKerberosLink
semanage port -a -t http_port_t -p tcp 8443
semanage fcontext -a -t httpd_sys_content_t "/etc/zerotrust(/.*)?"
restorecon -Rv /etc/zerotrust

Secure Boot¶

For enhanced security, enable Secure Boot on server hardware.

Disk Encryption¶

Use full disk encryption for servers storing sensitive data:

# Example using LUKS on Linux
cryptsetup luksFormat /dev/sda2
cryptsetup open /dev/sda2 encrypted-volume
mkfs.ext4 /dev/mapper/encrypted-volume

Monitoring Prerequisites¶

Metrics Collection¶

Set up Prometheus or compatible metrics collection:

# prometheus.yml
scrape_configs:
  - job_name: 'zerotrust'
    scrape_interval: 15s
    static_configs:
      - targets: ['zerotrust:9090']

Log Aggregation¶

Configure a log aggregation solution:

# filebeat.yml
filebeat.inputs:
- type: log
  enabled: true
  paths:
    - /var/log/zerotrust/*.log
output.elasticsearch:
  hosts: ["elasticsearch:9200"]

Backup Prerequisites¶

Ensure you have:

1. Backup Solution: For configuration and data
2. Secure Backup Storage: Encrypted and access-controlled
3. Backup Testing Procedure: Regular validation of backups
4. Disaster Recovery Plan: Documented recovery procedures

Compliance Prerequisites¶

Depending on your regulatory requirements, ensure:

1. Audit Logging: Configured for all security-relevant events
2. Data Retention: Policies for logs and credentials
3. Access Controls: Properly documented and implemented
4. Vulnerability Management: Regular scanning and patching

Pre-Installation Checklist¶

Use this checklist to verify all prerequisites are met:

• Hardware meets minimum requirements
• Operating system is supported and updated
• All required software is installed
• Network ports are properly configured
• AWS IAM permissions are set up
• Kerberos service principal is created
• TLS certificates are obtained
• Redis is properly configured
• Security controls are implemented
• Monitoring solutions are prepared
• Backup procedures are established
• Compliance requirements are addressed

Troubleshooting Prerequisites¶

If you encounter issues with prerequisites, refer to:

1. Troubleshooting Guide
2. Kerberos Configuration
3. AWS Integration
4. Security Hardening

Next Steps¶

Once all prerequisites are met, proceed to the Installation Guide to install ZeroTrustKerberosLink.