Getting Started with Hexamail Nexus: Quick Setup for Administrators

Hexamail Nexus: Complete Guide to Features and SetupHexamail Nexus is an email management and security solution designed for organizations that need reliable mail routing, filtering, and policy enforcement. It combines an SMTP gateway, anti-spam and anti-malware features, content filtering, transport rules, and reporting into a single appliance or virtual appliance. This guide walks through core features, typical deployment scenarios, installation and setup steps, configuration tips, and maintenance best practices.

What Hexamail Nexus Does (At a Glance)

Hexamail Nexus acts as a mail gateway placed at the edge of your mail environment. Key roles include:

Inbound and outbound SMTP gateway for centralized policy enforcement and delivery control.
Spam and malware filtering with configurable block/allow lists and quarantine.
Content filtering and data loss prevention (DLP) to enforce acceptable use and prevent leaks.
Transport rules and routing so mail can be directed to different back-end servers or relays.
Logging, monitoring, and reporting for compliance and operational visibility.

Key Features — Detailed

SMTP Gateway and Routing

Hexamail Nexus provides a full SMTP edge gateway. You can define listeners for various ports and protocols, create custom routing rules, and set up failover routes. It supports:

Multiple MX records and priority-based routing
Smart host routing to external relays
Domain-based routing and per-domain settings
TLS for encrypted SMTP between servers

Spam and Malware Protection

Nexus includes layered anti-spam techniques such as:

Real-time blacklists (RBLs) and reputation checks
Bayesian analysis and heuristic scoring
Attachment scanning and file-type blocking
Integration with external virus scanners or built-in AV engines
You can tune sensitivity, quarantine thresholds, and auto-release policies.

Content Filtering and DLP

Use content rules to inspect headers, body, and attachments for keywords, regex patterns, and file signatures. Common DLP uses:

Block or encrypt messages containing credit card numbers or SSNs
Prevent outgoing attachments beyond size/type policies
Enforce corporate acceptable-use language or disclaimers

Authentication, Encryption, and Protocols

Nexus supports SMTP authentication (AUTH), TLS (including STARTTLS), and can be configured to require specific authentication mechanisms for relays or users. It supports:

Opportunistic and mandatory TLS
Certificate management for inbound/outbound TLS
Authentication against LDAP/Active Directory for relay control

Quarantine, User Access, and Notifications

Messages flagged as spam or policy violations can be quarantined with configurable retention. Administrators can:

Provide end-users with a quarantine summary or digest
Allow administrators to release or delete messages
Configure bounce or auto-reply behaviors

Logging, Reporting, and Monitoring

Nexus logs SMTP transactions, filtering decisions, and delivery attempts. Reporting features typically include:

Message volume and spam statistics
Per-domain/per-user delivery metrics
Audit logs for policy changes and administrative actions
Integration with syslog/SIEM is supported for centralized monitoring.

Typical Deployment Topologies

Edge gateway in front of on-premises mail servers (Exchange, Postfix, etc.)
Cloud email relay for hybrid setups (on-prem <> cloud)
Outbound-only gateway to enforce DLP and archival before sending mail externally
Internal relay to segment departments or apply different policies per business unit

Installation and Initial Setup

System Requirements

Hexamail Nexus is commonly available as a virtual appliance (OVA/VM) or a physical appliance. Check vendor documentation for exact CPU, RAM, and disk recommendations based on mail volume. Typical small deployments start with:

2–4 vCPU, 4–8 GB RAM, 50–100 GB disk space
Larger environments require more resources and separate storage for logs/quarantine.

Deployment Steps (High-Level)

Obtain the appliance image or hardware and deploy it into your virtualization platform or rack.
Assign a static IP and configure DNS records (MX, SPF, hostname).
Access the web management console via HTTPS and complete the initial setup wizard (time zone, admin user, licensing).
Configure listeners (port 25 for SMTP, alternate ports if needed) and define relay and authentication settings.
Configure routing rules to deliver mail to your internal mail server(s).
Configure spam/malware policies, quarantine settings, and user notifications.
Test inbound and outbound mail flow thoroughly and adjust policies and tuning.

Configuration Examples and Tips

Basic MX Setup Example

Public DNS: set MX record pointing to your Nexus public IP or hostname.
In Nexus: create an inbound listener on port 25, enable TLS, and set your internal mail server as the destination route.

TLS Best Practices

Use valid CA-signed certificates for public-facing listeners.
Configure TLS minimum version to 1.2+ and disable insecure ciphers.
Enable opportunistic TLS for outbound connections, and require TLS for partners when needed.

Spam Tuning Workflow

Start with vendor-recommended default sensitivity.
Monitor quarantine volumes for 7–14 days.
Adjust scoring thresholds or add targeted allow/block lists.
Use message headers to trace why mail was flagged and refine rules.

DLP Rule Example (Credit Card)

Match regex for 13–19 digit sequences with surrounding context (e.g., “card”, “visa”, “mastercard”).
Action: quarantine or encrypt and notify sender/admin.
Exclude internal-to-internal mail or specific trusted senders.

Administration and Maintenance

Regularly update the appliance software and AV signatures.
Monitor disk usage for logs and quarantine stores; configure archiving or retention policies.
Rotate TLS certificates before expiry and audit cipher settings periodically.
Back up configuration and export it after significant changes.
Review quarantine and false-positive reports weekly, and adjust policies accordingly.

Troubleshooting Common Issues

Mail not accepted from the Internet: verify MX records, firewall rules permitting port 25, and that Nexus listener is active.
High spam in inboxes: review scoring thresholds, enable additional RBLs, and check for bypass rules.
Deliveries delayed: inspect queue logs, DNS resolution times, and destination server connectivity.
TLS negotiation failures: check certificate validity, supported TLS versions/ciphers, and SNI settings.

Integration Considerations

Active Directory/LDAP: configure secure LDAP binds for authentication and recipient verification.
SIEM: forward logs (syslog) to a central collector for correlation and alerting.
Archiving and journaling: route copies of outbound/inbound mail to an archive or compliance system.

Licensing and Support Notes

Licensing models vary (per-domain, per-mailbox, throughput tiers). Verify renewal terms and support SLAs. For mission-critical deployments, consider vendor support contracts and subscription for signature updates.

Security and Compliance

Use least-privilege admin accounts and enable role-based access if available.
Keep software and signatures patched to reduce exposure to zero-day threats.
Maintain retention and audit logs to meet regulatory requirements (e.g., GDPR, HIPAA) as applicable.

Conclusion

Hexamail Nexus is a versatile gateway appliance for organizations needing centralized mail filtering, routing, and policy enforcement. Proper sizing, careful policy tuning, and ongoing maintenance are key to a successful deployment. Start with conservative spam settings, validate mail flow end-to-end, and incrementally tighten security and DLP rules based on observed behavior.