Articles about firewall | UserComp.com

Limiting Outbound Traffic for Specific Servers/PCs in Win11 Firewall

Block outbound internet access for specific Windows 11 applications by creating a program-based rule in Windows Defender Firewall with Advanced Security.

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Ubuntu 22.4.4 LTS: UFW Firewall Allows SSH but Prevents Connection to Another Server

Resolve UFW blocking outgoing SSH connections by verifying default policies and adding explicit allow rules for the target server.

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Securing an Ubuntu Server for Development Purposes

Prevents unauthorized access and system compromise on Ubuntu development servers by configuring UFW, creating non-root users, and enforcing SSH key authentication.

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Setup SSH Connection with 3 Ubuntu Machines to Bypass a Firewall

Bypass restrictive firewalls to access internal services by chaining SSH connections through an intermediate Ubuntu host.

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Cloning Public Git Repositories for HPC Software Installation: A Firewall Consideration

Resolve Git clone failures on HPC clusters by configuring SSH-based cloning to bypass firewall restrictions blocking standard HTTPS ports.

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Firewall Detects Strange IPs in the Network

Resolve firewall alerts for strange IPs by verifying traffic legitimacy, isolating suspicious devices, and updating security policies.

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How to Block Port 135 on Windows 11 Using Windows Firewall?

Block port 135 on Windows 11 to prevent RPC exploits like WannaCry by creating inbound and outbound firewall rules.

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Tech Support: Not Reaching Domain via HTTPS Server Behind PfSense Firewall

Resolve HTTPS domain resolution failures behind PfSense by fixing port forwarding, virtual host routing, and SSL certificate binding.

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How to Block a Specific File Name Regardless of Location in Windows 11 Firewall

AppLocker blocks specific filenames like 123.exe from executing anywhere in Windows 11, solving the limitation of firewall rules that only target network traffic and fixed paths.

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Setting Up a Firewall on Ubuntu Network Gateway for a Virtual Network with VirtualBox

Resolve Ubuntu VirtualBox gateway routing failures by configuring iptables for IP forwarding since UFW does not support NAT or packet forwarding.

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Windows Firewall Blocking IIS FTP Connection

Resolve Windows Firewall blocking IIS FTP connections by enabling the FTP Traffic In TCP rule and configuring passive port ranges.

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UFW Temporarily Rejects Port localhost for Testing: A Tech Support Guide

Resolve localhost connection refused errors in UFW by adding explicit allow rules for the loopback interface.

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Managing Windows Firewall with Local Admin Permissions: Overriding Group Policy Limits

Resolve inability to override Windows Firewall Group Policy limits with local admin permissions by requesting policy adjustments instead of using unsupported methods.

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Configuring Firewall to Allow Docker Application Access to Virtual Machine

Resolve Docker container access failures from the host VM by configuring UFW or firewalld to allow inbound traffic on exposed ports.

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Configuring Firewall Rules for WireGuard: Allow Connections between PC1 (10.0.0.1) and PC2 (10.0.0.3)

Resolve blocked peer-to-peer communication between PC1 and PC2 by allowing inbound UDP traffic on the WireGuard listen port.

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Can't Delete Firewall Rules on macOS 15 (Sequoia)

Resolve inability to delete individual firewall rules on macOS 15 Sequoia by using the Firewall Options menu to revoke specific application permissions.

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Is my home network being attacked?

Detect home network attacks by identifying unauthorized devices, slow performance, and router log anomalies to secure your system.

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Configuring a 7-layer Virtual Firewall on M2 MacBook Sequoia for YouTube Video Categories

Resolve the inability to filter YouTube video categories on M2 MacBook Sequoia by using browser extensions or DNS services instead of the native firewall.

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Troubleshooting FTP Client Connection: Ports Open in Firewall?

Resolve FTP connection timeouts by configuring firewalls to allow port 21 and the passive mode data port range.

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Windows 10 creating multiple NetBIOS sessions to Microsoft

Resolve excessive outbound traffic to Microsoft services by disabling telemetry and managing Windows Update settings.

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Understanding Conflicting Rules in Windows Defender Firewall for PyCharm 2024.2.3

Resolve PyCharm 2024.2.3 firewall connectivity issues by removing duplicate inbound and outbound rules in Windows Defender Firewall Advanced Security.

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CSF Blocks FTP Downloads from Remote Servers in AlmaLinux 9/CentOS 7 Migration

Resolve FTP download failures in CSF by allowing passive port ranges for data connections during AlmaLinux 9 and CentOS 7 migrations.

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FTP Access Blocked Despite Rule Opened

Resolve FTP connection failures caused by blocked dynamic data channels by enabling the Windows Firewall FTP Server Extension and configuring passive port ranges.

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How to Enable App Connect Outbound Despite Blocked Default Microsoft Defender Firewall in Windows 10

Resolves Windows 10 app internet access issues by creating specific outbound firewall rules for blocked executables.

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How to Restore `git pull` Functionality on Windows: A Step-by-Step Guide

Resolves git pull failures on Windows by fixing SSH authentication errors, firewall blocks, and misconfigured agent settings.

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Understanding Strange Source Destination IP Address Entries in Win10 Firewall Log

Resolve confusion over strange source IPs in Windows 10 firewall logs by distinguishing between NAT translation, Windows Update traffic, and malicious scanning attempts.

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DynDNS to Server on Home Network is Slow From Same Network

Resolve slow DynDNS access from the same network by configuring split-horizon DNS to bypass NAT loopback overhead.

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OPNsense Hub Configuration for Blocking Communication between Two LANs

Isolate two LANs in OPNsense by removing allow rules to block inter-LAN traffic while preserving internet access.

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Iptables Not Dropping UDP Packets with Exact IP Address

Resolve iptables ignoring UDP drop rules by inserting them before permissive rules using the -I flag to ensure correct processing order.

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Unblock Windows Firewall for Specific IP Address in WSL 2

Resolve Windows Defender Firewall blocking inbound connections to WSL 2 services by creating an allow rule for the vEthernet adapter IP.

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Configuring Firewall Logging: Correctly Setting Up Logging for SRV1 and SRV2

Configure BIND on SRV1 to forward DNS query logs to SRV2 via syslog for centralized tracking.

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How to Create a Windows Firewall Rule for Traceroute

Resolve Windows Firewall blocking traceroute by allowing inbound ICMP Type 3, Type 11, and UDP high port traffic.

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Sony Bravia TVs Sending UDP Packets - Firewall Blocked

Resolve Sony Bravia TV UDP packet blocks by configuring firewall exceptions for the device's specific IP or MAC address instead of opening broad port ranges.

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WAN and LAN via the same physical port on a Teltonika router but with different firewall rules

Resolve inability to apply separate firewall rules for WAN and LAN on a single Teltonika Ethernet port by using multiple physical ports or VLAN tagging.

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Configuring Specific IP Addresses with DHCP Offer on Windows Firewall

Resolve APIPA issues by allowing UDP port 68 inbound traffic in Windows Defender Firewall for specific DHCP servers.

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Redirect Local Requests to IP to Other IP (Linux

Redirects local traffic destined for a specific IP to another IP on Debian 10+ using nftables output chain DNAT.

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How to Remove a Specific Access Denied Rule in Hyper-V Firewall for WSL2 Instances

Resolve WSL2 connectivity issues by removing specific Hyper-V firewall Access Denied rules using PowerShell.

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Cannot Ping Kali Ubuntu from Ubuntu: A VirtualBox Firewall Issue

Resolve ping failures from Ubuntu host to Kali Linux guest by allowing ICMP traffic through the UFW firewall.

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Traffic Not Passing OPNsense Firewall in Hyper-V: Troubleshooting Steps

Resolve OPNsense firewall traffic issues in Hyper-V by fixing virtual switch bindings, VLAN tags, and interface assignments.

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Unable to traceroute but able to ping

Resolve traceroute failures when ping succeeds by adjusting firewall rules to allow UDP or using TCP-based tools like tcptraceroute.

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Windows Server 2019 Firewall Settings Blocking Key Pair Authentication

Resolve Windows Server 2019 firewall blocking SFTP key pair authentication by configuring outbound rules for port 22.

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Secure Your Network with Proxmox Firewall: How to Block Traffic and Allow Specific IP Ranges

Configure Proxmox VE 8 firewall to block unauthorized traffic and allow specific IP ranges for SSH and Netbird services.

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MacOS Viscosity VPN blocks non-Apple app traffic

Resolve Viscosity VPN blocking non-Apple apps by adjusting DNS overrides and firewall permissions.

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UFW Firewall: Rules Not Working with VPN

Resolve UFW firewall rules ignoring traffic on VPN interfaces like tun0 by configuring explicit interface bindings or adjusting default policies.

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SSH Session via Apache Web Page on Ports 80/443

Configure HAProxy or Stunnel to tunnel SSH traffic through Apache ports 80 and 443, bypassing restrictive firewalls that block standard SSH connections.

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Troubleshooting: Unable to Connect to Port Despite Successful Ping

Resolve port connection failures despite successful ping by checking local firewall rules, service binding, and router port forwarding configurations.

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Troubleshooting Dropping Packets in iptables: tcpdump Analysis and Solutions

Resolve iptables packet drops by verifying chain policies, rule order, and using tcpdump to confirm traffic flow on the correct interface.

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Understanding the Use of I Option in Traceroute Command with Netfilter Firewall

Resolve traceroute timeouts caused by Netfilter dropping UDP probes by using the -I option to send ICMP Echo Requests instead.

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How is XP still vulnerable behind a NAT + firewall

Explains why Windows XP remains vulnerable behind NAT and firewalls due to outbound malware traffic, UPnP risks, and unpatched legacy vulnerabilities.

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Kubuntu UFW: Block Incoming, Allow Outgoing

Configure UFW on Kubuntu to block incoming and allow outgoing connections by installing, enabling, and verifying the default deny-incoming policy.

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