Tracer Wireless-N Broadband Router 11N, Руководство пользователя

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Wireless-N Broadband Router 11N – User Guide
ALG Service Settings
ALG (Application Layer Gateway)
In the context of computer networking, an ALG or application layer
gateway consists of a security component that augments a
fi rewall
or NAT employed in a computer network. It allows customized
NAT traversal
fi lters to be plugged into the gateway to support
address and port translation for certain application layer „control/
data” protocols such as FTP, BitTorrent, SIP, RTSP,
fi le transfer
applications etc.
In order for these protocols to work through NAT or a fi rewall,
either the application has to know about an address/port number
combination that allows incoming packets, or the NAT has to monitor
the control traf
fi c and open up port mappings ( fi rewall pinhole)
dynamically as required. Legitimate application data can thus be
passed through the security checks of the
fi rewall or NAT that would
have otherwise restricted the traf fi c for not meeting its limited fi lter
criteria.
Usually allowing client applications to use dynamic ephemeral TCP/
UDP ports to communicate with the known ports used by the server
applications, even though a
fi rewall-con fi guration may allow only a
limited number of known ports. In the absence of an ALG, either the
ports would get blocked or the network administrator would need to
explicitly open up a large number of ports in the
fi rewall; rendering
the network vulnerable to attacks on those ports.
In the default ALG settings, the following protocols have enabled. It
is recommended to keep the settings unchanged.
1,FTP
2,TFTP
3,PPTP
4,IPSec
5,L2TP
DMZ Settings
The DMZ function is to allow one computer in LAN to be exposed
to the Internet for a special-purpose service as Internet gaming or
videoconferencing.
DMZ Host IP Address: The IP address of the computer you want
to expose.
Enable: Click the checkbox to enable the DMZ host.
IMPORTANT: When enabled the DMZ host, the fi rewall settings of
the DMZ host will not function.
UPnP Settings
It supports latest Universal Plug and Play. This function goes into
effect on Windows XP or Windows ME or this function would go
into effect if you have installed software that supports UPnP. With
the UPnP function, host in LAN can request the router to process
some special port switching so as to enable host outside to visit the
resources in the internal host.
Enable UPnP: Click the checkbox to enable the UPnP.