User's Manual

Security
62
N600 Wireless Dual Band Router WNDR3400v3
game hosts serve data about other players’ moves. When a computer on the Internet sends a
request for service to a server computer, the requested service is identified by a service or
port number. This number appears as the destination port number in the transmitted IP
packets. For example, a packet that is sent with the destination port number 80 is an HTTP
(web server) request.
The service numbers for many common protocols are defined by the Internet Engineering
T
ask F
orce (IETF at http://www.ietf.org/) and published in RFC1700, “Assigned Numbers.”
Service numbers for other applications are typically chosen from the range 1024 to 65535 by
the authors of the
application. Although the router already holds a list of many service port
numbers, you are not limited to these choices. You can often determine port number
information by contacting the publisher of the application, by asking user groups or
newsgroups, or by searching.
The Block Services screen lets you add and block specific I
nternet
services by computers on
your network. This is called service blocking or port filtering. To add a service to block, first
determine which port number or range of numbers are used by the application.
 To block services:
1. Select Advanced > Security > Block Servic
es to display the following screen:
2. Select either Per Schedule or Always to enable service blocking, and click Apply. If you
selected Per Schedule, specify a time period in the Schedule screen as described in
Schedule Blocking on p
age 63.