https://ozgurkoca.com.tr/en/ Practical network engineering guides on FortiGate, Aruba Networking, ClearPass, enterprise networking, and real troubleshooting cases by Özgür Koca. en https://ozgurkoca.com.tr/en/troubleshooting/aruba-ap-314-iap-conversion-instant-cluster-join.html https://ozgurkoca.com.tr/en/troubleshooting/aruba-ap-314-iap-conversion-instant-cluster-join.html A real-world case where an Aruba AP-314 converted with an IAP image could discover the existing Instant cluster and complete config sync but still fall back to standalone SetMeUp mode, resolved by correcting conversion-related environment parameters. https://ozgurkoca.com.tr/en/how-to/fortigate-security-profile-department-based-design.html https://ozgurkoca.com.tr/en/how-to/fortigate-security-profile-department-based-design.html A practical guide to designing role-based FortiGate Security Profiles for Web Filter, Antivirus, Application Control, IPS, SSL Inspection, File Filter and DNS Filter, including profile groups, comments, staged enforcement and validation. https://ozgurkoca.com.tr/en/articles/aruba-controller-cluster-ap-load-distribution-failover-capacity.html https://ozgurkoca.com.tr/en/articles/aruba-controller-cluster-ap-load-distribution-failover-capacity.html A practical capacity-planning guide explaining why AP count alone is not enough in Aruba Controller Cluster environments, and how client load, throughput, CPU, memory, and failover capacity should be evaluated together. https://ozgurkoca.com.tr/en/articles/aruba-controller-cluster-vrrp-is-it-really-required.html https://ozgurkoca.com.tr/en/articles/aruba-controller-cluster-vrrp-is-it-really-required.html An architecture guide explaining what Aruba Controller Cluster and VRRP solve, with practical decision points for AP discovery, Layer-2 and Layer-3 clusters, gateway redundancy, and campus designs. https://ozgurkoca.com.tr/en/articles/fortigate-firmware-upgrade-decision.html https://ozgurkoca.com.tr/en/articles/fortigate-firmware-upgrade-decision.html A risk-based decision guide for FortiGate firmware upgrades, covering Feature vs Mature releases, Release Notes, Known Issues, critical service impact, SSL VPN, the official upgrade path, rollback planning, and validation. https://ozgurkoca.com.tr/en/troubleshooting/aruba-controller-cluster-isolated-node-recovery.html https://ozgurkoca.com.tr/en/troubleshooting/aruba-controller-cluster-isolated-node-recovery.html A systematic ArubaOS 8 troubleshooting and recovery approach for a controller cluster node in ISOLATED state, covering cluster membership, Config ID, configuration state, peer communication, and config/database synchronization. https://ozgurkoca.com.tr/en/troubleshooting/fortigate-sip-alg-session-helper-voip-troubleshooting.html https://ozgurkoca.com.tr/en/troubleshooting/fortigate-sip-alg-session-helper-voip-troubleshooting.html An advanced FortiGate VoIP troubleshooting approach for one-way audio, calls dropping around 32 seconds, and REGISTER issues that continue after SIP ALG is disabled, separating session-helper behavior, NAT/SDP/RTP, packet capture, and NPU visibility. https://ozgurkoca.com.tr/en/how-to/aruba-cx-mac-oui-device-profile.html https://ozgurkoca.com.tr/en/how-to/aruba-cx-mac-oui-device-profile.html A real-world Aruba CX configuration guide that uses Device Profile and MAC OUI matching to automatically apply port-access roles, VLANs, and trunk behavior to phones and access points. https://ozgurkoca.com.tr/en/how-to/fortigate-7-4-12-dialup-forticlient-ipsec-wizard.html https://ozgurkoca.com.tr/en/how-to/fortigate-7-4-12-dialup-forticlient-ipsec-wizard.html A step-by-step guide to creating a Dialup Remote Access IPsec VPN for FortiClient with the FortiOS 7.4.12 IPsec Wizard, including authentication, policy and routing, client options, and review steps. https://ozgurkoca.com.tr/en/how-to/aruba-cx-lacp-lag-configuration.html https://ozgurkoca.com.tr/en/how-to/aruba-cx-lacp-lag-configuration.html A practical guide to combining multiple physical ports into a single LAG interface on Aruba CX with LACP, adding member ports, configuring trunk VLANs, and validating the result. https://ozgurkoca.com.tr/en/troubleshooting/fortigate-proxy-based-web-filter-domain-match.html https://ozgurkoca.com.tr/en/troubleshooting/fortigate-proxy-based-web-filter-domain-match.html A real FortiGate Proxy-Based Web Filter troubleshooting case where vendor engineering confirmed invalid regular expressions in the WAD/Hyperscan regex database as the root cause of specific domains not being blocked.