Ceyhun KIRMIZITAS

17Oct 2026 by Ceyhun Kirmizitas 0 Comments

Field Guide: Kerberos Authentication in Exchange Server – Configuration and Validation

Exchange, Exchange Server SE / 2019 / 2016, Security & Hardening

Applies to: Exchange Server SE / 2019 / 2016 Microsoft is moving away from NTLM in Windows. For Exchange Server administrators, this raises an important question: What does this mean for Exchange client authentication, and where does Kerberos fit in? In discussions with customers, I sometimes get the impression that moving away from NTLM means everything in Exchange should use Kerberos. But that is not how Exchange works. Different clients and services use different authentication methods. Kerberos can help reduce NTLM dependency, but it cannot replace all of them. So I wanted to focus on three practical questions: Where does Kerberos really fit in Exchange Server? What does it take to configure it correctly? And how can we confirm that clients are actually using Kerberos rather than falling back to…

11Oct 2026 by Ceyhun Kirmizitas 0 Comments

Exchange Server and Teams Calendar Integration Without HCW

Exchange Server SE / 2019 / 2016, Microsoft Teams

Applies to: Exchange Server SE / 2019 | Microsoft Teams Microsoft Teams Calendar can be integrated with Exchange Server on-premises. Normally, we use the Hybrid Configuration Wizard (HCW) to configure the integration between Exchange Server and Microsoft 365. However, some customers keep all their mailboxes on-premises, with no mailboxes in Exchange Online. They use Microsoft Teams but do not need mailbox migration, hybrid mail flow, or other Exchange coexistence features. HCW can also configure additional Hybrid components, such as Organization Relationships, IntraOrganizationConnectors, and mail flow connectors, depending on the selected options. For this scenario, I wanted a more controlled approach. Instead of running HCW, I wanted to configure only the components required for Teams Calendar and understand what each one does. I started with basic Teams Calendar integration and then…

04Oct 2026 by Ceyhun Kirmizitas 0 Comments

Manage Exchange Server Transport Log Paths with ExchangeLogPathManager.ps1

Exchange Server SE / 2019 / 2016

Applies to: Exchange Server SE / 2019 / 2016 Exchange Server can generate a large amount of log data over time, especially Message Tracking, SMTP protocol, and connectivity logs. By default, these logs are usually stored under the Exchange installation path, which is commonly on the system drive. I created ExchangeLogPathManager.ps1 to make it easier to review and compare transport log paths across multiple Exchange servers, and safely move supported high-growth transport logs to a dedicated log drive when needed. The script works with supported Transport Service, Front End Transport, and Mailbox Transport log path settings. Version 1.1 also adds Interactive Configure and explicit Review modes while keeping the same Preview, confirmation, pre-change snapshot, drift protection, Apply, and verification workflow. Download ExchangeLogPathManager.ps1 Download from GitHub Questions and feedback are welcome…

02Oct 2026 by Ceyhun Kirmizitas 0 Comments

Manage Exchange Server URLs and Namespaces with ExchangeURLManager.ps1

Exchange Server SE / 2019 / 2016

Applies to: Exchange Server SE / 2019 / 2016 Configuring Exchange Server Client Access URLs is rarely a one-time task. The URLs are set after a new installation, checked again during migrations, changed when a server is replaced or the namespace design changes, and compared when a new server needs to match the existing ones. The Exchange commands themselves are not complicated. The harder part is everything around those commands: checking the current configuration, deciding what should be carried over, seeing exactly what will change, keeping a backup, and verifying the result afterward. That was the main reason I created ExchangeURLManager.ps1. The goal was not only to set Exchange URLs. I wanted one tool that could review the current configuration, compare Exchange servers, configure namespaces, clone the required settings, create…

27Sep 2026 by Ceyhun Kirmizitas 0 Comments

Exchange Server SE Readiness Check Before Installation

Exchange Server SE / 2019 / 2016

Applies to: Exchange Server SE RTM | Windows Server 2025 / 2022 / 2019 Over the years, I have seen many Exchange Server installations take longer than expected because of Windows Server, Active Directory, DNS, network, storage, or prerequisite problems. Even when Exchange Setup completes successfully, configuration differences can still cause unexpected behavior afterward. In some cases, recommended settings may also need to be reviewed and applied later. Many of these issues can be identified before Exchange Setup starts. That was the idea behind ExchangeServerReadinessCheck.ps1. I first created these checks for my own Exchange upgrade and migration work. Later, I added more checks based on different environments and real cases. This can be especially useful for Field Engineers, Consultants, and administrators who perform Exchange deployments, upgrades, or migrations periodically and…

23Sep 2026 by Ceyhun Kirmizitas 0 Comments

Windows 11 25H2 to 26H2 Upgrade: First Impressions

Windows 11, Windows Client

Applies to: Windows 11 26H2; upgrade from Windows 11 25H2 On September 23, 2026, Windows 11 version 26H2 appeared in Windows Update on my Windows 11 Enterprise laptop. I decided to upgrade from Windows 11 25H2, OS Build 26200.9448, to 26H2 and document the process. After the upgrade, I also checked some of the newer Windows features to see what had actually changed and how they worked in daily use. This article is based on my experience with Windows 11 Enterprise. Some features or options may be different on other editions or device configurations, and Windows features can change with future updates. I may update this article as I continue using 26H2. In This Article 1. Upgrading from Windows 11 25H2 to 26H2 2. Upgrade Experience 3. Taskbar Position and…

20Sep 2026 by Ceyhun Kirmizitas 0 Comments

Exchange Server Auth Certificate Field Guide: Validation, Rotation, Recovery, and Time Zone Issues

Exchange, Exchange Server SE / 2019 / 2016

Applies to: Exchange Server SE / 2019 / 2016 In a healthy Exchange Server environment, Exchange Server Auth Certificate renewal should normally be a straightforward process. In the field, however, I have seen cases where this process did not go as expected. Sometimes the certificate is still healthy. Sometimes it is close to expiration. In other cases, it is already expired, invalid, or missing from one or more Exchange servers. The correct action is not the same in every case. Because of this, I wanted to put together a practical guide based on the Exchange Server Auth Certificate cases I see in real environments. This guide shows how to check the current state, choose the correct path, renew or replace the certificate when needed, validate the result, and complete the…

19Sep 2026 by Ceyhun Kirmizitas 0 Comments

Recover the Microsoft Exchange Self-Signed Certificate Without EMS

Exchange, Exchange Server SE / 2019 / 2016

Applies to: Exchange Server SE / 2019 / 2016 / 2013 Exchange Server creates a self-signed certificate during setup. Its friendly name is normally Microsoft Exchange, and its subject is the Exchange server name. For example, if the server name is EX1901, the certificate subject is CN=EX1901. Normally, you do not need to touch this certificate. But if it is removed, or if the Exchange Back End HTTPS binding loses the certificate, OWA, ECP, ActiveSync, and Exchange Management Shell can be affected. Microsoft documents this problem and uses New-ExchangeCertificate to create a replacement certificate. One of the possible symptoms is that Exchange Management Shell itself cannot connect. This post shows a practical recovery path when EMS is not available. Microsoft's recovery article is scoped to Exchange Server 2013 and 2016;…

12Sep 2026 by Ceyhun Kirmizitas 0 Comments

Windows 11 25H2 System Tray Disappears – Restored After KB5124010 Preview

Windows 11, Windows Client

Applies to: Windows 11 25H2 Summary: On a Windows 11 25H2 VM, the entire system tray disappeared after installing KB5121003 and again after KB5120998 Preview. Removing KB5121003 brought the icons back on OS Build 26200.8037. On October 12, 2026, I installed KB5124010 Preview. After restarting Windows, the clock, network, volume and other system tray icons returned. This is what I observed on this VM; it is not a confirmed fix for every Windows 11 computer. Microsoft did not list this exact system-tray symptom as a known issue for KB5121003 when the original article was written. In This Article 1. KB5124010 Preview — System Tray Restored 1.1. How to Install KB5124010 2. Update Results 3. Final Thoughts 4. Earlier Updates and Rollback (Historical Reference Only) 4.1. Initial Environment and Build 4.2.…