Networking

This article shows a simple solution to a weird networking problem that plagued me for hours: IPv6 packets were sometimes lost; IPv4 was not affected. Problem: IPv6 Ping Timeouts and Packet Losses Symptom: Teams Issues I noticed the problem first when there were intermittent connectivity issues in Teams during a meeting.

This post explains how to configure DNS over HTTPS (DoH) for all WiFi networks in Windows 11 via the Settings app. Unfortunately, this is less intuitive than it should be; I need a reminder every time I connect to the German railway’s WiFiOnIce, which only seems to work with Deutsche Bahn’s (insecure) DNS server (you can switch to more secure DNS servers once you’ve accepted the terms on their captive portal).

I had a weird issue on my laptop: whenever I connected to our company’s VPN, I lost local internet connectivity. As it turned out, this was caused by incorrect network interface priority metric settings. To spare you and my future self many frustrating hours of troubleshooting, here’s what caused it.

This post lists the internet communication targets of Adobe Acrobat Reader, Photoshop, and Creative Cloud. This post is a part of my application network connection monitoring series, a group of articles that explain how to analyze the network traffic of any Windows or macOS app.

This post lists the internet communication targets of Citrix Virtual Apps and Desktops (formerly XenApp/XenDesktop). This post is a part of my application network connection monitoring series, a group of articles that explain how to analyze the network traffic of any Windows or macOS app.

This post lists the internet communication targets of the Microsoft Windows operating system, including its various services and UWP apps. This post is a part of my application network connection monitoring series, a group of articles that explain how to analyze the network traffic of any Windows or macOS app.

This post lists the internet communication targets of Microsoft Office and Teams. It is a part of my application network connection monitoring series, a group of articles that explain how to analyze the network traffic of any Windows or macOS app.

This is part 1 of my application network connection monitoring series, a group of articles that explain how to analyze the network traffic of any Windows or macOS app. The communication targets of the Windows OS and of many popular apps are listed in dedicated posts.

This article is for you if you want to improve privacy and block ads on all devices on your network without installing any software, simply by configuring a modern DNS service, yet with the ability to override settings for individual sites, and with nice dashboards thrown in for good measure.

This post describes a real-world configuration of the free VPN server SoftEther. It shows how to set up a VPN for macOS and Windows clients on a Hyper-V Windows guest VM.

Tools that monitor network traffic typically work with IP addresses, not server names. Humans, on the other hand, seem to prefer names over cryptic numbers. Most tools deal with that by doing reverse lookups of the IP addresses, i.e. they are looking for DNS PTR records. The result of such a lookup, however, is not always what you expect. Let us look at a simple example:

You have been there: end-users are complaining and your boss demands an explanation why “Citrix is slow” - again. You, the XenApp/XenDesktop admin, desperately look at Task Manager and Perfmon, but you cannot find a thing. Your servers are humming along quite nicely, but still: applications are slow, the system feels sluggish and logons are taking forever. And then, all of a sudden, things are back to normal. What was going on? How do you prevent that from happening again?

This is a collection of bugs, errors and problems I encountered working with Offline Files, along with possible solutions or at least workarounds. For more information about Offline Files see also my other articles about this topic.

A little known fact about the Windows Offline Files functionality is it slows down network operations considerably. Here is how and why. Test Results The following tests were performed with a set of 1,114 files of a total size of 408 MB. In the copy test the files were copied from a Windows 7 client machine to a file server over a 100 MBit LAN connection. In the delete test the files were deleted on the file server. No antivirus or other security products were running on either side. Each test was run twice, the table lists the average.

Windows Offline Files have a bad reputation. Many an administrator can tell a story where Offline Files caused issues that sometimes even required a reinstallation of the affected PC. But Microsoft has gradually improved the functionality and ironed out many of the bugs. Today - in Windows 7 SP1 with all post-SP1 fixes - Offline Files is a technology that still has its problems, but can be used in production - if you are adventurous. This article lists the gotchas I am aware of.

If you roll out Windows 7 in an enterprise environment you may need to decide what to do with IPv6. As you probably know, Windows 7 comes with IPv6 enabled by default. That is certainly nice, but what if your network does not “do” IPv6 yet? Should you disable IPv6 in Windows 7?