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Network & IT Infrastructure Expert | Mikrotik | VPN | Linux | Cloud With 25 years of experience in IT infrastructure and network engineering, I specialize in designing, securing, and optimizing network systems for businesses of all sizes. Whether you need a reliable VPN solution, a secure network setup, or an optimized server infrastructure, I can help you achieve your goals efficiently. What I Offer: Mikrotik & Network Configuration – Routing, Firewall, VLANs, QoS, Wireless VPN & Secure Networking – WireGuard, OpenVPN, IPsec, GRE tunnels Linux System Administration – Ubuntu, CentOS, Debian, server automation Cloud & Backup Solutions – Veeam, Rsync, ZFS, Proxmox, Disaster Recovery Server & API Hosting – OpenStreetMap servers, self-hosted solutions Troubleshooting & Performance Optimization – Network monitoring, security hardening I have worked with businesses, startups, and enterprise clients to ensure their IT infrastructure is secure, scalable, and high-performing. My approach is straightforward – I analyze, optimize, and deliver solutions that just work. Let’s connect and discuss how I can help with your project!

Solution-oriented, highly analytical and resourceful candidate with extensive experience in 3 Serbian banks. - over 5 years working experience in Microsoft Windows server editions 2003/2008 (active directory, DNS, DHC, NAT, WDS, WSUS, NAS, LAN, WAN etc.) - Over 10 years of working experience as a system administrator in Windows 2000/XP/Vista/ 7/ 8 editions. Provided installation, configuration, troubleshooting and customer assistance on both server and desktop platforms. Provided systems upgrade, installing new hardware and software. Expert knowledge of complete windows desktop systems, processes, peripherals, registry, Microsoft Office, hardware etc. Expert knowledge of help desk support and remote technical troubleshooting. Fast problem solving and multitasking, ability to analyze in-depth problems in short time. Used to work under preassure. 

I’m a Senior System and Network Engineer with over 18 years of hands-on experience in IT infrastructure, cybersecurity, and cloud environments. As the founder of AOVD Systems, I help businesses and professionals around the world design, secure, and optimize their digital environments — from local servers to global cloud platforms. ⸻ 🔧 What I Do I deliver end-to-end IT solutions that are secure, scalable, and cost-efficient. My core areas of expertise include: • 🖥️ System Administration & Virtualization – Microsoft Server, VMware, Hyper-V, ESXi • ☁️ Cloud & Microsoft 365 Migration – Azure AD, Exchange Online, Intune • 🔐 VPN Configuration & Network Security – IPSec, SSL VPN, SAML, Multi-factor Authentication • 🧱 Firewall & Endpoint Protection – Fortigate, SonicWall, Cisco, Huntress, FieldEffect, Defender for Business • 💾 Backup & Disaster Recovery – Veeam, Nable, Acronis, Anxient • 📈 Network Performance & Monitoring – PRTG, Nagios, ManageEngine, NetFlow Analyzer • 🔄 Managed IT Services & Remote Support – 24/7 monitoring, patch management, SLA-based response ⸻ 🌍 Who I Work With I’ve supported clients across Europe and the U.S., including: • Government and public institutions • Small and medium businesses seeking reliable IT outsourcing • Professional poker players and private clients requiring secure, anonymous, and latency-optimized VPN setups • Teams transitioning from local servers to the cloud or hybrid infrastructure I combine enterprise-level knowledge with a hands-on, personal approach — ensuring speed, security, and discretion at every step. ⸻ 🎯 Why Clients Choose Me • Proven track record of resolving complex infrastructure issues under pressure • Certified expertise across multiple vendor ecosystems (Microsoft, Cisco, VMware, Veeam) • Transparent communication and detailed technical reporting • Tailored solutions — I don’t copy-paste templates, I solve your specific problem “Vladimir fixed in one hour what others couldn’t in three days.” “Professional, responsive, and precise. My systems are finally stable.” ⸻ 🎓 Certifications & Training • Microsoft Certified Solutions Expert (MCSE) – Server Infrastructure • Cisco Certified Network Professional (CCNP) – Routing & Switching • VMware Certified Professional (VCP) – Data Center Virtualization • Veeam Certified Engineer (VMCE) – Backup & Replication • Microsoft 365 & Azure Administrator Associate • Nagios & PRTG Advanced Monitoring Implementation • ManageEngine Suite Training – Endpoint Central & NetFlow Continuous learning is part of my work ethic — I stay updated with the latest in cybersecurity, automation, and cloud technologies to deliver cutting-edge solutions to every client. ⸻ 🚀 Let’s Work Together Whether you need a VPN configuration, network performance audit, or complete IT infrastructure management, I’ll help you build systems that are secure, stable, and future-ready. 📩 Let’s connect — tell me about your IT challenge, and I’ll design a fast, professional, and cost-effective solution.

Skilled System Administrator and Network Engineer with over 20 years of hands-on experience, adept at organizing networks for single-office environments or multiple offices connected via VPN. I am highly proficient in Unix system administration (Linux and FreeBSD), covering DNS, DHCP, LAMP/LEMP, FTP, SMTP, SNMP, ACLs, firewalls, and NAT, BGP. My expertise also extends to major cloud platforms (AWS, Vultr, DigitalOcean) and virtualization technologies (vSphere, Hyper-V, Proxmox), as well as monitoring tools (Zabbix) and VoIP/IP telephony systems (Asterisk, FreePBX). Here is what past clients have said about my work: - “Pavel was fantastic! My project hit a snag and I needed an FTP server configured quickly. He jumped in immediately, resolved the issue in no time, and answered all my questions in a friendly manner. This guy is a real problem solver!” - “Very smart when it comes to Linux systems—was able to help with our issue.” - “A very skilled and professional expert who solved all additional and unexpected problems with patience. He overdelivered, and I highly recommend working with him!” - “The problem was solved quickly and efficiently.” - “Pavel did a great job tracing the problem and solving it.” - “Pleasure to work with.” I take pride in my ability to quickly diagnose issues, implement reliable solutions, and consistently exceed client expectations.

👑 Expert Vetted - Top 1% of all Upwork Freelancers - Top Rated Network and Cloud Engineer. - 300+ projects and 7000+ Upwork hours up to date. - 600k+ earned on Upwork. Networking vendors I have worked with: * Cisco, Mikrotik, Fortigate, Ubiquiti, Vyatta, VyOS, pfSense, Sonicwall, Sophos XG, Watchguard, Brocade, Ruckus, HP, Huawei, HPE, Aruba, Arista, etc. Cloud Skills: Terraform (AWS, Azure, GCP) AWS - VPC, EC2, RAM, R53, LB, S3, IAM/SSO, various NGFWs, Terraform. Azure - AD, AADDS, S2S VPNs, VMs, LB, NGFWs, Azure Hub-Spoke, Terraform. GCP - Cloud Compute, Security, NGFWs, Terraform. Digital Ocean Vultr ...

My name is Djordje(George) Colic. I live in Serbia. I am windows and linux server system administrator. I have MCSA certificate. For 8 years I was working as system administrator for Mcs systems from San Diego and Miami Lakes IT . This is remote job. I heave experience in using ConnectWise and Ninja RMM as remote management tools. I am logging in to remote networks via ConnectWise or VPN- L2TP/IPsec or OpenVPN and then I use RDP to login to server or any workstation. I am giving support to customers via phone, ConnectWise , RDP or TeamViewer. This support includes their servers, workstations, printers , support with their dedicated applications , office 365. I am giving suport to VOIP customers. They have AT&T Synpase or SkyTalk phone system. Synapse Gateways are PSTN 67010 or SIP 67070. Routers: I was working with SonicWall , Peplink , Mikrotik routers . I am in charge for the maintenance of customer’s and office servers and workstations . For automation tasks I am using batch and powershell scripts. Server OS: Windows Server 2016 or 2012. Workstations: windows 10 or 7. Linux server OS: Red Hat . I am logging in to linux servers via SSH to do every day management tasks. Virtualization: VMWare , HyperV. Cloud: I have experience working in AWS . Every network is Domain network with Domain Controller. For file server we are using Synology NAS where important documents are kept on network share. I am also using NAS as VPN server to access remote network. I have knowledge of Java programming and power shell. As DevOPS engineer , I was working for Avi . Our client had Ping Directory , Ping Proxy servers . There were different environments. Server OS: Red Hat Enterprise Linux Server release 7.9 . I was logging into client network via SSH. I have experience in managing linux servers.