Kerberos simple application reference architecture

The simple Kerberos instance Access Gateway architecture represents a set of components required for Kerberos based authentication and authorization using Access Gateway. It represents a baseline or starting point for other architectures.

This architecture is designed to meet the following requirements:

  • Protect a Kerberos (Windows IIS) based service.
  • Provide a baseline for testing and development.

Benefits and drawbacks

Benefits Drawbacks
  • Simple installation
  • Baseline for testing, proof of concept etc.
  • Can be used to replace VPN
  • Not fault tolerant.
  • No load balancing or high availability.
  • Not intended for production.
  • Administration server access requires SSH port 22, and HTTPS ports 443, be open. See Access Gateway deployment prerequisites for details.




Component Description
External internet Web clients

Traditional client browser accessing Access Gateway using known as [appN|consumer-app1] URLs.
URLs not shown

URL representing the application an external web client would enter to access one of the applications secured by Access Gateway. Typically all URLs of this nature are served by, and resolve to, the Access Gateway instance.

Okta org

Your Okta org, providing identity services.

Okta org Universal Directory

Okta universal directory, housed within an Okta org, containing users outside other LDAP/AD implementations. Typically these include other customer accounts, partner accounts and more.


External internet to DMZ

Traditional firewall between the external internet and the DMZ hosting Access Gateway.

DMZ Access Gateway Access Gateway cluster, located in the DMZ is used to provide access to applications used by external internet clients.
Contains a Kerberos service and a keytab.
See Create keytab for details of creating a keytab.
See Add Kerberos service for details of defining a Access Gateway Kerberos service.
Typically hosted in a virtual environment such as Amazon Web Services, MS Azure, Oracle OCI or something similar. See Manage Access Gateway deployment.

DMZ to internal firewall

Traditional firewall between DMZ and the internal network.

Internal network Service/Protected application

The set of protected web resources, in this case Microsoft Services, accessed using the URLs.

Supported versions:

  • Microsoft IIS IWA: IIS 7 or later
  • Microsoft OWA IWA: IIS 7 or later

Microsoft domain service instance with Key Distribution Center

Domain service containing a Key Distribution Center (KDC) . Typically a KDC uses an Active Directory database as its credential backing store.
During run time operation, the KDC instance services requests for Kerberos tickets which are then used with Kerberos enabled services such as Microsoft IIS.

Other considerations

DNS is typically split between external and internal domains. All external URLs, such as [appN|consumer-app1], would be served externally and point to the Access Gateway instance. Internal URLs, used by Access Gateway such as [protd-N|consumer-app1], would be served by internal DNS.

Most architectures forward log events to an external syslog component. Okta strongly recommends that a logging server be configured for all Access Gateway environments. See Configure log forwarders.

Additionally, Access Gateway itself is typically managed via internal access only. That is, administrators typically access Access Gateway itself from behind the firewall. This is shown in other architectures.

Related topics

Common Access Gateway flows

DNS use

High availability

About Access Gateway prerequisites