Security Tab / Firewall

High

In the High operating level, both inbound (traffic sent from the internet to your home network) and outbound (traffic sent from your home network to the internet) connections are restricted.

Outbound traffic is allowed for the following services:

• HTTP and HTTPS (TCP ports 80, 443)
• DNS (TCP/UDP port 53)
• NTP (UDP ports 119, 123)
• Email (TCP ports 25, 110, 143, 465, 587, 993, 995)
• VPN (GRE, UDP port 500, TCP port 1723)
• iTunes (TCP port 3689)

All other outbound traffic is blocked by the firewall.

All unsolicited inbound traffic is blocked, and Intrusion Detection is enabled.

Medium

In the Medium operating level, only inbound connections are restricted by the firewall. Outbound connections are allowed by the firewall regardless of the service or port(s) being used for the connection.

Inbound traffic is blocked for the following services:

• IDENT protocol (TCP port 113)
• ICMP (ping) request
• Peer-to-Peer applications
• Kazaa (TCP/UDP port 1214)
• BitTorrent (TCP ports 6881-6999)
• Gnutella (TCP/UDP port 6346)
• Vuze (TCP ports 49152-65534)

Intrusion Detection is enabled in the Medium operating level. All other inbound traffic is allowed by the firewall. Please note that unsolicited inbound traffic will not be forwarded to devices on your home network unless they match a port forwarding/triggering rule, or a DMZ host has been configured.

Low

The Low operating level is the default setting for your gateway's firewall.

Outbound connections are allowed by the firewall regardless of the service or port(s) being used for the connection.

Inbound traffic is blocked for the following services:

• IDENT protocol (TCP port 113)

Intrusion Detection is enabled in the Low operating level. All other inbound traffic is allowed by the firewall. Please note that unsolicited inbound traffic will not be forwarded to devices on your home network unless they match a port forwarding/triggering rule, or a DMZ host has been configured.

Custom

Selecting Custom operation allows specific configuration of your firewall settings.

In Custom mode, outbound connections are allowed by the firewall regardless of the service or port(s) being used for the connection.

Inbound connections may be blocked by checking their corresponding options in the configuration page:

• Block HTTP (TCP port 80, 443)
• Blocks inbound HTTP requests sent to your home network.
• Block ICMP
• Prevents your gateway from responding to ICMP Ping requests from internet devices.
• Block Multicast
• Blocks inbound multicast traffic from internet devices.
• Block Peer-to-Peer applications
• Blocks incoming traffic on ports commonly used by peer-to-peer file sharing applications.
• Block IDENT
• Blocks incoming RFC1413 Identification requests from internet devices.