Recent posts tagged networking

For work I needed to connect to a private network over L2TP/IPsec. The VPN client built into Windows 10 refused to connect at all, and it gave me nothing to debug with: no log of the key exchange, no hint about which step failed. I went looking for a...

This checklist shows how to review people, devices, profile revisions and pending setup records using existing approved sources. Each unresolved item should end with an owner and a next action. Adapted with permission from A Periodic VPN Access Revi...

This guide sets out a small naming convention for issued VPN profiles. It covers readable assignment labels, revision suffixes, matching client names, and what to keep out of filenames. Adapted with permission from A Practical VPN Profile Naming Con...

A useful IP-check comparison records the address family, raw address, timing, and lookup labels separately. This keeps a database disagreement from becoming an unsupported diagnosis. Adapted with permission from the original Lisar articlehttps://lis...

17NAS IPv6 Test — free online IPv6 connection test Not sure if your network really supports IPv6? This free tool checks it in real time, right in your browser. What it shows: Your IPv4 and IPv6 addresses side by side Connection latency for each ...

A profile reissue needs a small, useful change record: the assignment, the old-to-new revision, and which setup stage has actually completed. The record should help the next person continue without receiving any secrets. Adapted with permission from...

A VPN configuration prompt is a system permission decision. This guide separates that decision from profile import and connection state, including why switching VPN apps on Android can bring the prompt back. Adapted with permission from the original...

This checklist explains how to verify a VPN after a device restart, including network readiness and the difference between client launch settings and Android traffic-blocking policy. Adapted with permission from the original Lisar articlehttps://lis...

Adapted from Removing VPN Access When Someone Leaves: An Offboarding Checklisthttps://lisar.io/articles/vpn-offboarding-access-removal by Mohammad Hesameddin Montazerilisar, published July 9, 2026 and updated September 27, 2026. AI assistance was use...

Adapted from VPN and Video Calls: Realistic Expectationshttps://lisar.io/articles/vpn-video-calls-expectations by Mohammad Hesameddin Montazerilisar, published July 9, 2026 and updated September 27, 2026. AI assistance was used for editing and the in...

When an application backend sleeps between requests or takes time to start, an Android app can mistake a temporary cold start for a permanent outage. The opposite failure is also common: a loading spinner retries forever and gives the user no clear w...

When a filtering change appears to have no effect, waiting is useful only after you know which setting and resolver the client is using. This checklist keeps the diagnosis focused. Adapted with permission from the original Lisar articlehttps://lisar...

Introduction Wireshark dissector for a proprietary protocol found on TP-Link Tapo cameras, dissecting device discovery packets on ports UDP/20002 and UDP/20004, as well as control and media stream packets on port TCP/8800 and keep-alive packets on ...

A VPN client can hold several profiles with nearly identical labels. If the selected entry is wrong, even a careful connection test may describe the wrong configuration. Start by resolving the profile identity through its source, assignment, and inte...

A VPN setup that behaves differently after an operating-system update needs a controlled comparison. The profile may be unchanged while the client environment, permissions, or network behavior has changed. Identify the failing stage before replacing ...

I'm back again after a loong break but this time I have done a lot of things apart from what I said in the last blog obviously 🙃. This time I'll be discussing on how I wrote the logic for using TCP in an event loop even though it is a stream oriente...

Ever needed to show one app window on a tablet without any remote-desktop software? I built WindowStream for exactly that, and Ive just open-sourced it. Its a small Windows tray app that streams a chosen window as MJPEG over HTTP on your local ne...

Volumetric Distributed Denial of Service DDoS and transport-layer flooding attacks pose an existential challenge to modern cloud infrastructure, edge gateways, and container workloads. Conventional Linux packet filtering utilities such as Netfilter...

Cover: Conceptual illustration; may be AI-generated. Original creation method is unverified. The alert, padlock and location symbols are illustrative, not a real account incident, current application screenshot or security test. Image from the Lisar ...

Cover: Conceptual illustration; may be AI-generated. Original creation method is unverified. Symbols do not represent tested security or a current application screen. Image from the Lisar Website archive. Before working from a hotel, airport or cowo...