Four profiles, one click each — and picking the wrong one either breaks your internet or switches your firewall off. Here is what High, Medium, Low and No Filtering actually do, in plain words.
Most of the confusion around this tool comes from its four profiles. The names sound like strength levels, but they are really four different answers to a single question about outbound traffic with no matching rule. Understand that one question and every profile becomes obvious.
The four profiles are not four firewalls. They are four answers to one question: when a program tries to connect out and no rule mentions it, what happens? Inbound traffic stays blocked by default in High, Medium and Low. Only the outbound default changes — and that one change is the whole personality of each profile.
High blocks all outbound connections, even ones that have allow rules in some descriptions of the mode it is simplest to treat it as: nothing leaves. It is the profile for a short emergency — you suspect something is wrong, or a technician is inspecting the machine.
Do not live here. Browsers, updates, mail, licensing checks — everything stops, and the PC looks broken within minutes. High is a tool you visit, not a home.
Medium blocks outbound connections that do not match an allow rule, and lets the matched ones through. This is the profile the tool recommends and the one the notification system is built for: the first time a real program asks, you allow it once and a rule is born; junk never gets a rule and stays blocked.
Low allows outbound connections that have no rule, and only blocks the programs you have explicitly denied. This is Windows' own default personality with better visibility. It is honest protection against known-bad programs, but it cannot stop a new unknown program from phoning home — nothing asks you anything.
No Filtering turns Windows Firewall off. Not paused, not relaxed — off, inbound and outbound. The only honest use is the rare case where a different, real firewall product is actively managing the machine. If you ever find a family PC sitting on No Filtering with nothing else installed, you have found a wide-open door, whatever the person who set it believed at the time.
One more distinction that saves confusion later: changing the profile changes only the default answer for connections no rule mentions. It does not rewrite, delete or weaken the rules you already made. A program you blocked always stays blocked on Medium and Low alike, and a program you allowed keeps its rule on every profile. That is why experimenting is safe — Medium for a week tells you the truth about your software, and switching back costs nothing if it is not for you.
Profiles, prompts and rules — the whole Firewall Control walkthrough is in the video.
▶️ Watch Full VideoMedium Filtering. It is marked as the recommended profile because it blocks unknown outbound connections while letting your allowed programs work — the only profile where the notification prompts can do their job.
No. Profiles change the default behaviour for connections without rules; your existing rules stay in Windows Firewall and keep applying. Switching profiles is safe to try and safe to undo.
Very close in spirit: Windows by default allows outbound traffic that has no block rule. Low Filtering keeps that behaviour inside this tool, which is why it protects mainly against programs you have specifically chosen to block.