53 votes
Accepted

How to tell which windows firewall rule is blocking traffic

(Note: this method has been working at least on Windows 7, 10 Pro, Server 2012 R2) Following steps will lead you to the rule blocking your connection: Open a Windows console (with Administration ...
  • 746
34 votes
Accepted

How to detect if a network is blocking outgoing ports?

tl;dr Run this command to test a specific port (fast). time nmap -p 22 portquiz.net Run this command to test popular ports (slow). time nmap portquiz.net Run this command to test all ports (...
30 votes
Accepted

Using Windows Firewall to block a specific IP on Windows 10

Open Windows Firewall with Advanced Security by running wf.msc. On the left, select Inbound Rules, then under the Action menu, choose New Rule. On the Rule Type page, choose Custom. On Program, ...
  • 39.3k
26 votes

Is it possible to create firewall that only allows legitimate webserver traffic on port 443 and not any other service?

Yes, and they don't need any magic here, just trivial matching on the TCP packet contents. Even though SSH and TLS (SSL) encrypt their payloads, the protocol headers themselves are still ...
  • 400k
23 votes
Accepted

Cannot ping a Windows 11 machine

After poking around I managed to enable ICMP responses on my Windows 11 machine: Open Windows Defender Firewall and select Advanced Settings in the sidebar. Switch to Inbound Rules via the Getting ...
  • 466
22 votes

How to block everything (all incoming and outgoing internet access) except those applications are in firewall white-list?

You do not need any 3rd party firewall software. By default windows firewall functions as follows: Inbound - Block all unless in the list (Whitelist) Outbound - Allow all unless in the list (...
  • 331
21 votes

How to config Windows firewall so VM Host-only can ping Windows 7

I ran into this issue recently when I started doing Linux development on a Windows laptop where the source code was on the host and it was shared over CIFS* to compile on a CentOS VM. Open Windows ...
19 votes
Accepted

How to open a firewall port in Windows using Power Shell

You can refer to the guide here. The command to open port 80 is: netsh advfirewall firewall add rule name="Open Port 80" dir=in action=allow protocol=TCP localport=80 You need to specify: name ...
  • 3,983
18 votes

Is it possible to put UFW on CentOS?

Since ufw is available in the EPEL repository, it can be directly installed as a package: yum install -y epel-release yum install -y ufw
  • 181
17 votes

Am I paranoid, or are corporate firewalls censoring entire countries?

I've seen a variety of vendors doing content filtering based on country of origin. China and Russia are usually the ones with filtering turned on by default, or at least have some kind of alerting ...
17 votes
Accepted

What are the IP ranges to block the entire Russian Federation?

7,255 IP address blocks assigned to the Russian Federation As of June 2018, there are over 7,200 IPv4 address blocks assigned to the Russian Federation. The largest of them, with 524,288 addresses ...
  • 1,754
16 votes
Accepted

What does it mean if a public IP address looks like a private IP address?

There are several ranges of 'private' ip addresses, as defined in RFC1918. These are: 10.0.0.0 - 10.255.255.255 (10/8 prefix) 172.16.0.0 - 172.31.255.255 (172.16/12 prefix) 192....
  • 16.1k
15 votes
Accepted

How to block range of incoming IPs in Windows Advanced Firewall

First calculate the sub-network CIDR notation. In 13.54.0.0 to 13.54.255.255 IPv4 range, the first two octates are constant (the network prefix) and the remaining last two octates are variable (host ...
  • 10.5k
15 votes
Accepted

PFSense Stuck At "Please wait while the update system initializes" while uninstaling or upgrading any package

Check your pfSense version. I had to update from pfSense 2.4.5_1 to pfSense 2.5.0. That solved the problem for me.
  • 166
15 votes

PFSense Stuck At "Please wait while the update system initializes" while uninstaling or upgrading any package

I had to go to System / Update / Update Settings and set to previous stable version 2.4.5 deprecated bc I am still on 2.4.5-RELEASE-p1. After doing that, package manger didn't show any updates for a ...
  • 151
13 votes
Accepted

How do I stop my Mac from asking to accept incoming network connections?

This might be caused by a missing or wrong digital signature. Like Apple explains: If you run an unsigned app that is not listed in the firewall list, a dialog appears with options to Allow or Deny ...
  • 30.8k
13 votes

How to block everything (all incoming and outgoing internet access) except those applications are in firewall white-list?

In an elevated shell window, do Set all profiles to block inbound/outbound traffic: netsh advfirewall set allprofiles firewallpolicy blockinbound,blockoutbound Remove all rules: netsh advfirewall ...
  • 261
13 votes
Accepted

Windows 10 defender firewall MpsSvc and Internet Sharing Services (ICS) consuming high CPU usage

I had the same issue on Windows 10, Firewall + ICS service constantly taking up 10% of CPU time. I don't have Windows Defender enabled so couldn't follow the top answer's instructions. Instead: ...
  • 4,425
12 votes

Is there a simple way to detect ISP port blocking?

This will take a lot of time but will get you the list of all blocked ports: #!/bin/bash COUNTER=1 while [ $COUNTER -lt 65535 ]; do echo $COUNTER curl portquiz.net:$COUNTER --...
  • 223
12 votes
Accepted

Why does NTP require bi-directional firewall access to UDP port 123?

You only need allow incoming traffic NTP's ports if you are acting as a server, allowing clients to sync to you. Otherwise, the existance of an NTP state will automatically determine whether the ...
  • 196
12 votes

Windows 10 defender firewall MpsSvc and Internet Sharing Services (ICS) consuming high CPU usage

I was having the same issue but I do use Windows Defender's firewall. Resetting the firewall defaults worked for me. I found the fix at https://answers.microsoft.com/en-us/windows/forum/windows_10-...
12 votes
Accepted

firewall-cmd - add-forward-port don't work

THE REAL PROBLEM: The command... firewall-cmd --permanent --zone=public --direct --add-rule ipv4 filter FORWARD 0 -d 0.0.0.0/0 -j ACCEPT firewall-cmd --permanent --zone=public --add-forward-port=...
11 votes

What are Inbound and Outbound Rules for Windows Firewall?

Outbound means you initiate the connection and the traffic starts flowing outward of your computer to the destination you intended. Example you connect to a server. Inbound means someone else from ...
10 votes
Accepted

How forward packets from network interface to another

You'll need some sort of masquerading statement. The reason behind this is that, currently, packets arriving from eth2 to eth1 are identified by 10.101.0.0/16 addresses. Those 10.101.0.0/16 packets ...
  • 558
10 votes
Accepted

Why can ping.exe get the IP of a domain with no responding?

Why can I get the IP of the domain with no responding? Because you don't actually get the IP address from the domain itself. You always get it from a separate database – the DNS (Domain Name System). ...
  • 400k
9 votes

How to permanently disable firewall in Red Hat Linux

For version 7 of CentOS or RedHat Enterprise you must use the command systemctl. For example: #Check status: systemctl status firewalld #Stop firewall: systemctl stop firewalld #Disable firewall:...
9 votes

How to block docker-mapped ports with a firewall from outside the host without messing up docker routing inside the host?

It looks like I can bind my exposed container ports to localhost only. docker run -d -p 127.0.0.1:9009:9009 someserver
  • 261
9 votes
Accepted

Shares not accessible by other computers if Windows 10 firewall is ON

I manually added a rule to the firewall to open TCP port 445. This resolves the issue by allowing SMB2 and SMB3 over TCP. However, this solution is less than ideal since it does not answer the problem ...
  • 311
9 votes
Accepted

Allow PowerShell remote access only from one address

Like explained in this article: Enabling PowerShell remoting for only a specified set of IP addresses. (for each client pc1/pc2/pc...) you have to: enable-psremoting next: remove the winrm-listener ...
  • 740
9 votes
Accepted

Windows 10 Firewall warns about being disabled on every login

You can disable Windows Defender Firewall with Group Policy. In the administrative templates for the computer, go to Network | Network Connections | Windows Defender Firewall | Standard Profile (or ...
  • 39.3k

Only top scored, non community-wiki answers of a minimum length are eligible