About a23

a23 is an Australian owned Systems Integrator headquartered in Canberra. We provide specialist ICT services across diverse technologies and are recognised as a valued strategic partner for Government and private sector organisations. a23 has grown to become a prominent strategic partner, focused on servicing the needs of small to medium-sized agencies to deliver quality outcomes through expert people, great relationships, and fit-for-purpose technologies.

Why work for a23?

a23 is a well-established Australian technology company experiencing strong growth, fuelled by rising demand for our expertise in Cyber Security, Networking, Cloud, Data and AI, and Hybrid Cloud. We bring the agility and innovation of a start-up backed by the maturity, credibility, and delivery assurance of an established market leader.

Our teams deliver secure, scalable solution to government and enterprise client, blending deep technical capability with a client-first culture. Whether enabling AI-driven insights, transforming hybrid infrastructure, or securing mission-critical environments, a23 is trusted to deliver at a national scale.

We offer a collaborative and flexible working workplace alongside a range of employee benefits such as an annual wellbeing allowance. For more information, see Our Careers - A23.

The Role a23 is seeking a Senior Microsoft 365 Exchange Engineer. This full-time contract position reports to the Practice Lead – Modern Workplace and allocated to one of our valued customers. This role is part of the team supporting the secure, reliable and effective operation of Microsoft Exchange environments across on-premises, hybrid and Microsoft 365 cloud platforms.

If you enjoy taking ownership of complex messaging issues, leading Exchange migrations and delivering secure, reliable outcomes for customers, you will enjoy a23.

This role operates in a hybrid arrangement, with attendance at customer sites and the a23 office as required. You will use your Microsoft Exchange and Microsoft 365 expertise to design, implement, migrate, administer and support enterprise messaging environments.

Role responsibilities

Exchange and messaging

- Design, implement,



maintain and support Microsoft Exchange Server and Exchange Online environments.
- Administer and support on-premises, hybrid and Microsoft 365 cloud messaging platforms.
- Configure and manage mail flow, message hygiene, retention and compliance controls.
- Troubleshoot complex email, identity, messaging, performance and availability issues.
- Monitor messaging service health and resolve technical, security and operational risks.

Migration and security

- Lead Exchange migrations, including hybrid and cloud transformation projects.
- Support integrations with Entra ID, Active Directory and related identity services.
- Configure and support email security controls including SPF, DKIM and mail-routing technologies.
- Ensure messaging environments meet security, compliance and operational requirements.

Service delivery

- Develop and maintain solution designs, architecture documentation, operating procedures and as-built documentation.
- Collaborate with infrastructure, identity, security and cloud teams to deliver reliable service outcomes.
- Engage with project managers, executives, technical teams, customers and vendors as required.
- Provide technical leadership, guidance and mentoring to other engineers.

Desired Skills and Experience

Experience, Qualifications and Key Attributes

- Must be an Australian Citizen with the ability to obtain and maintain an Australian Government Security Clearance.
- Extensive practical experience supporting Microsoft Exchange Server and Exchange Online
- Strong knowledge of hybrid Exchange deployments and Microsoft 365 Platform (Teams, SharePoint)
- Demonstrated experience working in a highly secure Government or enterprise environment
- Demonstrated experience across the following:
- Entra ID / Azure Active Directory and Active Directory
- PowerShell
- Email security, SPF and DKIM




- Mail flow and mail-routing technologies
- Ability to adapt to changing priorities and work collaboratively and effectively in a fast-paced, growing and dynamic environment.
- Excellent organisation, communication and stakeholder management skills with the ability to manage multiple priorities in parallel.
- Ability to work independently and as part of a team.
- Relevant Microsoft, cloud, messaging or IT service management qualifications and certifications are highly regarded.
- Highly desirable skillset that will see candidates set themselves apart include:
- Experience leading Exchange Online migrations and cloud transformation projects
- Experience developing solution designs, architecture documentation and operating procedures
- Experience working in Australian Government or other secure environments

a23 Policy Handbook and Mandatory Training On commencing with a23, all employees and subcontractors are provided with the a23 Policy Handbook and asked to acknowledge their understanding and commitment to adhering to its policies. All employees and subcontractors are also assigned a suite of mandatory training that is required to be completed on an annual basis. All a23 workers are to take all reasonable care of their own health and safety and ensure that their actions do not adversely affect the health and safety of others.

Inclusive recruitment at a23

a23 value all career paths and experience so if you do not meet all the qualifications or requirements state for this role, we would still love to hear from you!

a23 is an equal opportunity employer committed to a diverse, inclusive, healthy and safe work environment. We are dedicated to attracting, retaining and developing our people regardless of gender identity, ethnicity, sexual orientation, disability, age and neurodiversity. We invite people of all backgrounds and identities to submit their application. Applications are strongly encouraged from the Aboriginal and/or Torres Strait Islander, LBGTQIA+ and neurodivergent communities.

Apply now! Applications will be assessed as they are received and as such the recruitment process may be finalised prior to the closing date.

📌 Senior Microsoft 365 Exchange Engineer (Canberra)
🏢 A23
📍 Canberra