Dragomir Ristic

EIM doo

EIM doo • Vollzeit

Feb 2023 - Present • 3 yrs 3 mos

As a System Administrator and Infrastructure Engineer at EIM d.o.o., I am responsible for designing, operating, and maintaining a complex on-premises and hybrid IT infrastructure that supports multiple business units and production-critical systems. My responsibilities include administration of VMware vCenter and ESXi clusters, managing the full virtual machine lifecycle, resource allocation, high availability, backups, and performance optimization. I work extensively with Windows Server environments, including Active Directory, Group Policy, DNS services, file services, and IIS for hosting internal and customer-facing applications. I manage Linux servers used for application hosting, automation, monitoring, and backend services. This includes administration of Nginx, SSL/TLS configuration, certificate lifecycle management, and system hardening to ensure secure and reliable operations. A significant part of my role involves Kubernetes, where I deploy, manage, and troubleshoot containerized applications, handle networking and ingress, manage secrets and configurations, and ensure scalability and resilience of services. I administer GLPI for ITSM and asset management, integrating infrastructure, tickets, and operational workflows to improve visibility and reporting. I also manage Zimbra email systems as well as Office 365, including user administration, mail flow, and service configuration in hybrid environments. For monitoring and security, I work with Pulseway for infrastructure monitoring and automation, and Bitdefender GravityZone for endpoint security management across servers and workstations. This role requires strong cross-platform expertise, security awareness, troubleshooting skills, and the ability to operate and support enterprise-grade systems in a demanding production environment.

MediasInc

MediasInc • Vollzeit

May 2011 - Mar 2024 • 12 yrs 10 mos

As a System Administrator at MediasInc, I was responsible for managing and maintaining core IT infrastructure and communication systems supporting daily business operations. I administered VoIP and telephony platforms, including Asterisk and FusionPBX, handling SIP configuration, extensions, call routing, troubleshooting, and system availability. I also managed vTiger CRM, supporting sales and support teams through user administration, permissions, backups, and integrations. My responsibilities included Microsoft Hyper-V virtualization, where I provisioned and maintained Windows Server virtual machines, managed resources, snapshots, backups, and recovery processes. I also supported Remote Windows Desktop environments, ensuring secure and reliable access for distributed users. I was responsible for email administration via WHM/cPanel, including domain and mailbox management, DNS configuration, spam filtering, and mail delivery monitoring. In addition, I served as administrator for multiple collaboration platforms: Zoom — account and security administration Slack — workspace and user management OpenFire (Spark) — internal messaging server administration This role required strong troubleshooting skills, cross-platform system integration, security awareness, and the ability to maintain stable, business-critical systems in a multi-service environment.