ZyXEL Communications NSA-220 Plus User Manual page 151

• IDP (Intrusion Detection and Prevention) to detect malicious packets within
normal network traffic and take immediate action against them.
• Anti-virus to check files you download for computer viruses.
BitTorrent and Your Firewall
The anti-virus feature on a firewall probably cannot check BitTorrent downloads
for viruses, so use anti-virus software on your computer to scan the NSA for
viruses.
When you download using BitTorrent, many other BitTorrent users are also trying
to download the file from you. The firewall slows this down because by default, it
only allows traffic from the Internet in response to a request that originated on the
LAN (it lets you get files from the Internet and blocks those on the Internet from
getting files from you).
Figure 40 Firewall Blocking Incoming BitTorrent Requests
To speed up BitTorrent file transfers, configure your firewall's port forwarding to
send incoming TCP port 6881 and UDP port 6880 connections to the NSA. You
probably need to use your firewall's HTML (web-based) configuration interface to
NSA-220 Plus User's Guide
Incoming BitTorrent Requests Blocked
Outgoing BitTorrent Request Allowed
Corresponding BitTorrent Reply Allowed
Chapter 7 Applications
151