Hire the Best Firewall Developers
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I have over 12+ years of practical working experience in VPN (Openvpn, IPSec, PPTP, IPSec/L2TP), Networking (Cisco Nexus, ISE, Juniper, Mikrotik, Ubiquiti) firewall (Sonicwall, Watchguard,Fortigate, Sophos, checkpoint, ASA, Palo Alto), Cloud system (AWS, Digital Ocean, Azure), WAF (F5), Cisco ISE, Mail server (SPF,DKIM,DMARC records) and troubleshooting. Apart of that have working experience on Azure sentinel, 365 Defender, Defender for Cloud, Nessus Also I am holding the following vendor certification 1. Cisco Certified Network Associate 2. Red Hat Certificate of Expertise in Server Hardening 3. Red Hat Certificate of Expertise in Server Hardening 4. Red Hat Certified Virtualization Administrator - (RHCVA) 5. Red Hat Certified Engineer (RHCE) 6. Red Hat Certified System Administrator (RHCSA) 7. Red Hat Certified System Administrator in Openstack 8. ISC2 - Certified in Cybersecurity Certification 9. AWS Certified Solutions Architect - Associate I am interested to work on any project related to VPN, Network and cloud Security, Cisco, VoIP, Asterisk, FreePBX, Elastix, IP Networking, Firewall, Linux system administration, and network/server troubleshooting.

I am a Dynamic, Dedicated, Passionate and Quickly Adaptable Freelancer with Technological innovations. I am a 🏅Upwork-Skill-Certified Freelancer with ✅100% JSS ✅ 70%+ Long-Term Clients ✅ 80%+ Clients Recommendation ✅ 90+ Active and Completed Jobs with Positive Feedback🏅Architect Certified on Sophos, Fortinet Firewalls and Endpoints Managements ✅ Others Certification on Network and Security✅ Strong and long Experiences on Fortinet, Sophos, SonicWall, Palo-Alto, PFSense Infrastructures Deployments, Migration and Managements✅ Any kinds of Wireless and Voice Solution Deployments✅ Network, System Security & Compliance Managements✅ Strong Experience on Routing & Switching🏦 Long-Experience with MSP, Corporate and Solution/Service-Provider Sectors. 🏦 Already worked with 90+ clients from different regions such as Asia, Africa, US, Europe etc. 🎖️Certifications (Completed & Enrolled) • Upwork Skill Certification - Customer Service. • Certified Architect by Sophos and Fortinet. 🏅 Sophos Certifications: • Sophos-Firewall v19.5-Engineer. • Sophos Firewall v19.5-Architect. • Sophos Firewall v19.5 to v20.0 Certified Architect Delta (AU80). • Sophos Firewall v19.5 to v20.0 Certified Engineer Delta (EU80). • Sophos Firewall v20.0 to v21.0 Certified Architect Delta (AU80). • Sophos Central Endpoint and Server v4.0-Engineer. • Central Endpoint and Server v4.0-Architect. • Sophos Central Endpoint v4.0 to v5.0 Architect Delta (AU15). • Sophos Central Engineer Delta v4.0 to v5.0 (EU15). 🏅 Fortinet Certifications: • NSE-7 (Network Security Architect) –NSE-ID:- 0Qjbf0qGSd • NSE-4 (Network Security Professional) – NSE-ID:- GThFxY1viO • NSE-5 (Network Security Analyst) on FortiAnalyzer- NSE-ID: - 8gIRCniwPN. • NSE-1 (Network Security Associate) By Fortinet License Number: OYBF7cetpL. • NSE-2 (Network Security Associate) By Fortinet License Number: FTsFjlmHck. 🏅 Other Certification: • CNSS (Certified Network Security Specialist) By ICSI, UK License Number: 18427811 • Cisco Certified Network Associate (Routing & Switching) Cisco-ID: - CSCO13303817 Here, I would like to share my Working experiences, fields of expertise and much more- ✅ I have 9 years plus hands-on experiences on Network, System, Security administration, Deployment and Migrations on different Infrastructures along with direct involvements/cooperation on different known issues from Deployment stage to end-user’s support. ✅ Fields of Specialization: 1. Because of having 9 years plus exclusive experiences on different Fortinet, Sophos, SonicWall, PFSense, Palo-Alto and other Infrastructures Deployments and Administration I can work with the Complete Design, Deployments, Migrations and Integrations on these Different types of Infrastructures such as- • Fortigate, Forti-APs, Forti-Switches, FortiVoice-Enterprise, Forti-Manager, Forti-EMS,FortiAnalyzer, FortiAuthenticator, FortiNAC, Fortinet Security Fabric Devices, FortiSandbox, FortiToken/Mobile/Service. • Sophos Infrastructures Managements such Firewalls, Endpoints, Switches, APs etc. • SonicWALL Infrastructures Managements such as Firewalls, NSM, Capture-Clients Endpoints etc. • Palo-Alto, Barracuda, PfSense, Cisco-Firepower, Firepower-Thread Defence and FMC and Others Firewalls Managements. • Migration To/From any of these above Infrastructures. 3. Long experiences on the Network and System Administration on these Infrastructures- • Routing & Switching on Cisco, Mikrotik, Juniper, HP, Dell, Aruba etc. • Wireless Implementation on Cisco, Aruba, Ruckus, 4Ipnet, Unifi/Ubiquiti, Forti-AP, Cambium, Altai, TP-Link-Omada, Teltonika etc. • Mail-Server Administration on Office365, G-Suite by Google, Zimbra etc. • Windows Server Managements. • Virtualization & Datacentre Managements on VMware, ESXi, vSphere or VCenter, Hyper-V, Synology-NAS/SAN and Others. • Voice Solution implementation on renowned Voice Solution Providers such as FortiVoice Enterprise, Grandstream, 3cX, Synway, Yeastar-PBX, FreePBX etc. • Endpoint Solution Deployments on TrendMicro, Sophos Endpoint Protection, FortiClient by Forti-EMS (Endpoint Management Server), ESET etc. • Complete Video Conferencing Solution on Dahua, Polycom etc. • Surveillance, Attendance reader solution on Hikvision, Dahua, ZKTecho, Handuri etc. 4. I am a quick and dynamic learner. I can adjust myself with the Technological innovation within a very short amount of time. 5. I am a technical person with a Never Give-Up character. I have multiples valuable feedback with great reviews on Upwork. You can also have a look at that. If you have any further query on me just send "Hi" in Upwork.

With over 8+ years of hands-on experience in the Core Data & Telecommunications industries, I specialize in Data/IP Networks, MPLS & network security. My expertise is in Design & Planning Network implementation, troubleshooting, Network administration, IT related solutions & managing large-scale service provider networks. With a specialized focus on Social Media Integration services, I bring over 8+ years of hands-on experience in the field.

I am a highly skilled network troubleshooter with 10+ years of experience in the networking and security field. As a certified CCNA, CCNP (Enterprise & Security), CCSA, NSE4, MTCRE, and MTCNA professional, I specialize in custom project-based solutions that enhance network performance, security, and scalability. I have hands-on experience in Banking, Corporate, Garments networks, Security Projects, and Managed Service Providers (MSPs), delivering high-quality, reliable, and detail-oriented solutions tailored to business needs. Key Skills & Expertise: ✔ Network Troubleshooting & Optimization ✔ Routing Protocols – BGP, OSPF, EIGRP, RIP ✔ Switching Technologies – VLAN, STP, PVST, VTP, LACP, PAgP, Bridge ✔ Security & Firewalls – Cisco FTD, Checkpoint, FortiGate, Sophos ✔ VPN Solutions (Multi-Vendor) – IPsec, GRE, L2TP, PPTP, IPIP, EoIP, PPPoE ✔ Access Control (ACLs) – Cisco Routers & Switches ✔ Wireless & LTE – Channel Bonding, MIMO, WDS, Mesh Networks ✔ QoS & Traffic Optimization – FIFO, RED, SFQ, PCQ ✔ MikroTik Expertise – Load Balancing, Failover, Bandwidth Management, Web Proxy, DHCP, PCC/PBR Routing, Static NAT/PAT, SNMP, Scripting Professional Certifications: 🏆 Fortinet Network Security Expert (NSE4) 🏆 Checkpoint Certified Security Associate (CCSA) 🏆 Checkpoint Certified Security Expert (CCSE) 🏆 Palo Alto Networks Certified Network Security Engineer (PCNSE) 🏆 Cisco Certified Network Professional (CCNP-Security & CCNP-Enterprise) 🏆 Cisco Certified Specialist - Enterprise Core 🏆 Cisco Certified Specialist - Enterprise Advanced Infrastructure Implementation 🏆 Cisco Certified Network Associate (CCNA) (Cisco-ID: CSCO13422865) 🏆 MikroTik Certified (MTCNA, MTCRE) I am committed to delivering top-tier network security and performance solutions with a dedication to excellence. Let’s collaborate to take your network infrastructure to the next level!

I’m S M Nazmul Hasan, CEO of Kolpolok Limited, trusted by cybersecurity companies, SaaS providers, and VPN startups in 65+ countries. Over the past decade, I’ve delivered VPN solutions that power millions of daily connections. I build scalable, reliable VPN platforms that drive real business growth. 💡𝗦𝗼𝗹𝘂𝘁𝗶𝗼𝗻𝘀 𝗜 𝗗𝗲𝗹𝗶𝘃𝗲𝗿 𝗳𝗼𝗿 𝗬𝗼𝘂 ➡️ End-to-End VPN App Development: ✔ Multi-platform VPN apps for iOS, Android, Windows, macOS, Fire TV, and browsers ✔ Fully white label vpn solutions with 𝗰𝗼𝗺𝗽𝗹𝗲𝘁𝗲 𝘀𝗼𝘂𝗿𝗰𝗲-𝗰𝗼𝗱𝗲 𝗼𝘄𝗻𝗲𝗿𝘀𝗵𝗶𝗽 ✔ Seamless in-app purchases, user authentication, and multi-language support ✔ Intuitive UI/UX design focused on conversion and retention ➡️ White-Label VPN SDK Integration: ✔ WL VPN SDK integration with scalable custom backend solutions ✔ Integration with PureVPN White Label SDK and other leading providers ✔ Ready-to-launch SDKs customized to your brand and user requirements ✔ Full technical support for integration, testing, and deployment ➡️ Multi-Protocol Backend Infrastructure: ✔ Support for OpenVPN, WireGuard, IKEv2, Shadowsocks, VMess, VLESS, IPsec, OpenConnect, Singbox compatible infrastructure ✔ Scalable VPN admin panel dashboards with user management, and analytics. ✔ Real-world traffic optimization, load balancing, and redundancy configurations ✔ Compliance-ready architecture aligned with GDPR, SOC2, and ISO standards 💡𝗪𝗵𝘆 𝗖𝗹𝗶𝗲𝗻𝘁𝘀 𝗖𝗵𝗼𝗼𝘀𝗲 𝗠𝗲 I don’t just build apps, I build VPN ecosystems tailored to your business model. ✔ Total Code Ownership – You own the complete source code from day one ✔ Business-First UX – Apps designed for real users, not just developer functionality ✔ Security & Compliance – ISO-certified workflows, and robust encryption standards ✔ Scalable Architecture – Built to grow with your user base, handling thousands of concurrent connections ✔ Rule-Based Routing & Split Tunneling – Optimized configurations for China and restricted regions ✔ Complete Documentation – Clean code documentation ✔ Manual Training & Technical Support – Hands-on guidance for your internal team ✔ Fast Delivery – Fast responses, and transparent progress updates ✔ 𝗧𝗼𝗽-𝗥𝗮𝘁𝗲𝗱 𝗣𝗹𝘂𝘀 𝗨𝗽𝘄𝗼𝗿𝗸 𝗖𝗼𝗻𝘁𝗿𝗮𝗰𝘁𝗼𝗿 ✔ 𝟭𝟬𝟬%+ 𝗝𝗼𝗯 𝗦𝘂𝗰𝗰𝗲𝘀𝘀 𝗥𝗮𝘁𝗶𝗻𝗴 ✔ 𝟵𝟬% 𝗔𝗯𝗼𝘃𝗲 𝗥𝗲-𝗵𝗶𝗿𝗲 𝗥𝗮𝘁𝗲 📝𝗣𝗿𝗼𝘃𝗲𝗻 𝗧𝗿𝗮𝗰𝗸 𝗥𝗲𝗰𝗼𝗿𝗱 Delivered 150+ projects in 65+ countries across 5 continents ✔ Developed VPN apps with millions of downloads and 4.9+ star average ratings across Google Play, App Store, and Trustpilot ✔ Supported long-term client growth with performance-focused infrastructure enhancements 👤𝗪𝗵𝗼 𝗜 𝗦𝘂𝗽𝗽𝗼𝗿𝘁 & 𝗪𝗼𝗿𝗸 𝗪𝗶𝘁𝗵 ✔ Startups, SaaS, and tech firms launching their first VPN product to enter this booming market ✔ Entrepreneurs and VPN resellers seeking high-performance white-label apps with fast deployment ✔ Agencies and consultancies adding VPN to their service portfolio for recurring revenue streams 💡𝗥𝗲𝗰𝗲𝗻𝘁 𝗙𝗼𝗰𝘂𝘀 𝗔𝗿𝗲𝗮𝘀 ✔ Open Connect, WireGuard, OpenVPN, Sing Box optimization for faster connections and lower battery usage ✔ Advanced obfuscation techniques to bypass censorship firewalls ✔ Payment gateway integrations for subscription-based VPN monetization ✔ VPN reseller admin panels with automated user and license management ✔ Multi-protocol hybrid backend design for global coverage and redundancy 𝗟𝗲𝘁’𝘀 𝗕𝘂𝗶𝗹𝗱 𝗬𝗼𝘂𝗿 𝗩𝗣𝗡 𝗕𝘂𝘀𝗶𝗻𝗲𝘀𝘀 You’re not just hiring a VPN developer. You’re partnering with an expert who understands the technical, business, and security dimensions of building VPN products that scale. If you’re ready to deploy a secure, scalable, and revenue-generating VPN solution under your brand, send me a message. I’ll respond within 24 hours with a tailored roadmap to bring your VPN vision to life. 𝑰𝒏 𝒂𝒅𝒅𝒊𝒕𝒊𝒐𝒏 𝒕𝒐 𝒇𝒖𝒍𝒍-𝒔𝒕𝒂𝒄𝒌 𝑽𝑷𝑵 𝒔𝒐𝒍𝒖𝒕𝒊𝒐𝒏𝒔, 𝑰 𝒉𝒆𝒍𝒑 𝒇𝒐𝒖𝒏𝒅𝒆𝒓𝒔 𝒂𝒏𝒅 𝒑𝒓𝒐𝒅𝒖𝒄𝒕 𝒕𝒆𝒂𝒎𝒔 𝒃𝒓𝒊𝒏𝒈 𝒆𝒂𝒓𝒍𝒚-𝒔𝒕𝒂𝒈𝒆 𝒊𝒅𝒆𝒂𝒔 𝒕𝒐 𝒍𝒊𝒇𝒆 𝒘𝒊𝒕𝒉 𝒊𝒏𝒕𝒖𝒊𝒕𝒊𝒗𝒆 𝒅𝒆𝒔𝒊𝒈𝒏 𝒂𝒏𝒅 𝒍𝒆𝒂𝒏 𝒅𝒆𝒗𝒆𝒍𝒐𝒑𝒎𝒆𝒏𝒕 𝒔𝒕𝒓𝒂𝒕𝒆𝒈𝒊𝒆𝒔. ✔ MVP Development for Fast Launch Agile MVP's tailored to validate your core concept, reduce time-to-market, and attract user traction—without unnecessary features or costs. ✔ UI/UX Design that Converts Crafting modern, user-focused interfaces for mobile and web apps—built to engage, retain, and grow your audience from day one. ✔ Fleet & VTS Tracking – Real-time GPS tracking and fleet optimization systems ✔ IoT Solutions – Smart, connected platforms with real-time automation ✔ AI Integration – Predictive, data-driven features to power growth Whether you're testing a new product or refining an existing one, I ensure your app is not just functional—but user-loved and market-ready. Let’s connect to launch your brand and lead the market today!

As a highly skilled and experienced professional with over 08+ years of expertise, I hold notable certifications such as CCNP, CCNA, RHCE, and Certified Ethical Hacker (CEH) . I have established myself as an accomplished network, system, and security engineer, capable of delivering complete solutions for designing, configuring, automating, and managing network and system projects. My proficiency in using simulation software such as Packet Tracer and GNS3, as well as real-life network and system devices, make me a valuable asset for any project. My few hands-on experiences is: ⭐Network Design by MS Visio, Cisco packet tracer, GNS3, and EVE-NG ⭐Netacad CCNA and CCNP packet tracer Labs activities, projects design and solution ⭐ Expert in configuring, managing, and troubleshooting Cisco routers, switches, FTD, FMC, and ASA firewalls. ⭐ Expert in configuring, managing, and troubleshooting Fortigate, Sophos, Check Point, SonicWall, Palo Alto, pfSense, OPNsense & Huawei firewalls, ⭐Netgear, Huawei, Aruba switch, DrayTek router, TP-Link and others vendor wireless router configurations. ✅Cisco, Tp-Link, Aruba, Fortinet, Ubiquiti, Planet, Huwei switch configurations. ⭐Proficient in configuring, managing, and troubleshooting Unifi Enterprise Fortress Gateway, UDM Pro, Unifi Cloudkey, USG UniFi Firewall , Security Gateway, Switch, and AP devices. ⭐Expert in Linux administration, with expertise in Ubuntu, Red Hat, openSuse, CentOS, Debian, and Kali Linux distributions. ⭐Expert in Windows server administration , Active Directory management, Exchange Server administration, DNS configuration, DHCP implementation, and Windows operating system support. ⭐Experienced in managing and configuring virtualization platforms including HYPER-V, VMware ESXi, VMware Workstation, KVM, VirtualBox, and Proxmox. ⭐Servers: HP Proliant Servers, Dell/EMC Servers, IBM ⭐MikroTik Routers configuration ✅ Cloud Administrator: Azure, AMAZON AWS , Google GCP, OVH and Digital Ocean ⭐VLSM/subnetting of small to large enterprises ⭐VLANs, Inter-VLAN routing, VTP, CDP, Ether-Channel(LACP, PAGP), Spanning Tree (STP, PVST++, MSTP), and FHRP Protocols ⭐IPV4 & IPV6 IP planning, DHCP, NAT/PAT configuration and IP helper address ⭐static and Dynamic Routing protocols (RIP, OSPF, EIGRP, BGP) configuration ⭐Layer-3 Redudent/backup links Using HSRP, VRRP ⭐Port security, ACL( access list) configuration ⭐Network troubleshooting and optimization ⭐VPN Configuration Expert (GRE , SSL, IPSEC, PPTP, OPENVPN , wireguard & DMVPN) ⭐Advanced Excel skills, including macro, VBA, VLOOKUP, and other automation techniques ⭐Network automation script for any cisco and fortigate devices using python ⭐ Skilled in automation using Bash/Shell scripting ✅Overlay Networks VPN Expertise: Proficient in configuring and managing various overlay network VPNs, including ZeroTier, Tailscale, WireGuard, SoftEther VPN, Netbird , Netmaker, OpenVPN Cloud, I, Twingate and PeerVPN for secure, scalable, and decentralized networking, enabling seamless remote access, team collaboration, and encrypted communications across distributed systems. ✅Beryl AX and Flint Router Configuration Expert ( Mini Router, Travel Router, Home Wi-Fi, cellular Router) like GL-MT6000, GL-AXT1800, GL-MT3000, GL-A1300 etc ✅Cisco Duo: MFA, 2FA, SSO, Identity Security Integration, Windows Logon, RDP, Microsoft AD, VPN Authentication.