User Manual

42D-Link DSL-520B ADSL2+ Modem User Manual
Section 7 - Device Info
Additionally,portforwardingenablesyoutoredirecttractoadierentportinsteadoftheonetowhichitwasdesignated.
Forexample,ifyouhaveaWebserverrunningonyourPConport8080andyouwanttograntaccesstothisservertoanyone
whoaccessesDSLrouterviaHTTP.Toaccomplishthis,doasfollows:
Step 1
DeneaportforwardingrulefortheHTTPservice,withthePCIPorhostname.
Step 2
Specify 8080 in the Forward to Port eld.
AllincomingHTTPtracisforwardedtothePCrunningtheWebserveronport8080.Whensettingaportforwardingservice,
ensurethattheportisnotusedbyanotherapplication,whichmaystopfunctioning.AcommonexampleiswhenusingSIP
signalinginVoiceoverIP,theportusedbythegatewayVoIPapplication(5060)isthesameport,onwhichportforwardingis
set for LAN SIP agents.
Note: Some applications, such as FTP, TFTP, PPTP and H323, require the support of special specic application level gateway (ALG)
modules in order to work inside the home network. Data packets associated with these applications contain information that allows
them to be routed correctly. An ALG is needed to handle these packets and ensure that they reach their intended destinations. DSL
routerisequippedwitharobustlistofALGmodulesinordertoenablemaximumfunctionalityinthehomenetwork.TheALGis
automatically assigned based on the destination port.
Virtual servers are congured for this purpose.