Firewall & Layer 7 Application Filtering

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Firewall & Layer 7 Application Filtering

Objective

Validate that the zWAN Gateway Router correctly blocks specified traffic between LAN devices by creating individual Flow Classification rules for:

  • Packet Matching (IP/Port based)
  • DPI-based Application Control (e.g., SMB traffic)

Prerequisites

  • Admin access to zWAN Director UI or device local UI.
  • Two Windows devices connected to the z40 LAN subnet (wired on LAN00 or Wi-Fi on LAN05).
  • Firewall and Flow Classification enabled on the device.

Test 1: Packet Matching Rule — Block Specific IP/Port Between LAN Devices

Steps

  1. Baseline Connectivity Check
  • From Windows Device A, confirm connectivity to Windows Device B on the target port (e.g., TCP 3389 for RDP).
  • Use tools like ping, mstsc, or telnet for verification.
  1. Create Packet Matching Rule
  • Login to zWAN Director UI.
  • Navigate: Security > Firewall > Rules tab.
  • Click NEW RULE. The Flow Classification dialog opens.

General tab:

  • Sequence number assigned automatically.
  • Comment: “Block RDP TCP 3389 LAN devices”.
  • Apply To: Routed and Bridged Packets.
  • Action: DROP (silent block) or REJECT.
  • Status: Enabled.

Packet Matching tab:

  • Input Interface: Select LAN00 or LAN05 (based on device connectivity), leave NOT unchecked.
  • Output Interface: Select same interface, leave NOT unchecked.
  • Source Address (optional): IP of Device A.
  • Destination Address: IP of Device B.

Protocol Matching tab:

  • Protocol: TCP
  • Destination Port: 3389

Leave DPI and Web Categories tabs empty.

  • Click CREATE.
  1. Validate Blocking
  • From Device A, attempt RDP to Device B; connection should be blocked.
  • Confirm other traffic (e.g., ping) works normally.
  1. Review Logs
  • Navigate to Security > Firewall Logs or Monitoring > Events tab.
  • Confirm blocked packets log with correct IPs, ports, timestamp, and rule comment.
  1. Persistence Check
  • Reboot z40 if possible; verify rule and blocking persist.

Test 2: DPI-Based Application Control Rule — Block SMB Traffic

Steps

  1. Baseline Connectivity Check
  • On Device B, share a folder.
  • From Device A, access the shared folder via \\DeviceB_IP or \\DeviceB_Hostname. Confirm access.
  1. Create DPI SMB Block Rule
  • Login to zWAN Director UI.
  • Navigate: Security > Firewall > Rules tab.
  • Click NEW RULE.

General tab:

  • Sequence automatic.
  • Comment: “Block SMB LAN traffic”.
  • Apply To: Routed and Bridged Packets.
  • Action: DROP or REJECT.
  • Status: Enabled.

Packet Matching tab:

  • Input Interface: Select LAN00 or LAN05.
  • Output Interface: Same as Input.
  • Leave source/destination empty unless restricting scope.

DPI tab:

  • In Filter box, type smb.
  • Select one or both: smbv1smbv23.
  • Leave other tabs empty.
  • Click CREATE.
  1. Validate Blocking
  • From Device A, attempt to access Device B shared folder; connection should be blocked.
  • Confirm other LAN traffic works normally.
  1. Review Logs
  • Check Firewall Logs or Monitoring > Events for SMB block entries with details.
  1. Persistence Check
  • Reboot device if possible; confirm blocking persists.

Notes & Tips

  • Use Wi-Fi (LAN05) to simplify hardware requirements for LAN testing.
  • Confirm Windows Firewall does not interfere.
  • Sequence numbers are auto-assigned; order matters in rule evaluation.
  • The NOT checkbox in interfaces inverts matching; leave unchecked for these tests.
  • Adjust rule scope with source/destination IPs for targeted blocking if desired.
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