Allied Telesis AT-WR4500 manual Firewall Filter, Submenu level /ip firewall filter

198	AT-WR4500 Series - IEEE 802.11abgh Outdoor Wireless Routers
	RouterOS v3 Configuration and User Guide

9Firewall and QoS

9.1Filter

9.1.1 General Information

Summary

The firewall implements packet filtering and thereby provides security functions that are used to manage data flow to, from and through the router. Along with the Network Address Translation it serve as a tool for preventing unauthorized access to directly attached networks and the router itself as well as a filter for outgoing traffic.

Quick Setup Guide

To add a firewall rule which drops all TCP packets that are destined to port 135 and going through the router, use the following command:

/ip firewall filter add chain=forward dst-port=135 protocol=tcp action=drop

To deny acces to the router via Telnet (protocol TCP, port 23), type the following command:

/ip firewall filter add chain=input protocol=tcp dst-port=23 action=drop

To only allow not more than 5 simultaneous connections from each of the clients, do the following:

/ip firewall filter add chain=forward protocol=tcp tcp-flags=syn connection-limit=6,32 action=drop

Specifications

Packages required: system

License required: Level1 (P2P filters limited to 1) , Level3

Submenu level: /ip firewall filter

Standards and Technologies: IP, RFC2113

Hardware usage: Increases with filtering rules count

RelatedTopics

IP Addresses and ARP

Routes, Equal Cost Multipath Routing, Policy Routing

NAT

Mangle

Packet Flow

9.1.2 Firewall Filter

Submenu level: /ip firewall filter

Description

Network firewalls keep outside threats away from sensitive data available inside the network. Whenever different networks are joined together, there is always a threat that someone from outside of your network will break into your LAN. Such break-ins may result in private data being stolen and distributed, valuable data being altered or destroyed, or entire hard drives being erased. Firewalls are used as a means of preventing or minimizing the security risks inherent in connecting to other networks. Properly configured firewall plays a key role in efficient and secure network infrastrure deployment.