What HGS does
Host Gateway Server is a .NET service that brokers encrypted, authenticated UTS terminal connections between client workstations and Unisys mainframes — replacing the cost and complexity of a VPN with a focused gateway tuned for legacy emulation traffic.
System roles
An HGS deployment is split into roles. Most sites collapse several roles onto one server; larger sites split them across machines for scale and isolation.
- Communications Server — runs the HGS service that brokers client-to-host traffic. Exactly one instance.
- Database Server — Microsoft SQL Server 2008 RTM or later. Holds configuration and session state. Exactly one instance.
- Configuration Management — the HGS Configuration Manager UI; one or more installs on servers or admin workstations.
- Monitoring — the HGS Session and Performance Monitor; zero or more installs.
- Utility Deployment Site — optional ClickOnce site for distributing the monitor; any web server.
Note: All starred components in the manual must be members of the same Active Directory domain unless they live on the same machine, in which case domain membership is optional.
Pre-installation checklist
- Windows Server with .NET Framework installed and current updates applied.
- SQL Server 2008 or later, reachable from the communications server.
- Service account and admin/operator/user groups defined in Active Directory.
- DNS / firewall rules in place for the planned client-facing port.
- Server certificate ready if SSL/TLS will protect client connections.
Installation steps
- Install role-based prerequisites on each target server (communications, database, configuration management, monitoring).
- Run the HGS installer and select the features for that machine.
- Configure the SQL Server connection and create the HGS database.
- Run the Configuration Manager to add client interfaces and host routes.
- Install the license and start the HGS service.
- Optionally publish the Session and Performance Monitor as a ClickOnce deployment site.
SSL / TLS setup
When client traffic must be encrypted, install a server certificate into the local computer's personal store and grant the HGS service account read access to its private key. The Configuration Manager exposes the certificate thumbprint on each client interface so HGS can present the right certificate per binding.
Troubleshooting client connections
- Confirm the HGS service is running and listening on the bound IP/port.
- On OS 2200 hosts, verify the open-id and station-name assignments match the route definition.
- On MCP hosts, verify the T27 virtual destination resolves and is enabled.
- Check the session monitor for closed-session messages — table 7 of the manual maps each message to a likely cause.