D-Link DWC-1000 User Manual - Page 209

Wireless Controller Figure 111 : Lis t of us e r de fine d s e rvice s . User Manual 7.5 ALG support Advanced > Firewall Settings > ALGs A p p licat io n Lev el Gat eway s (A LGs ) are s ecu rit y co mp o nent t hat en h ance t h e firewall an d NA T s u p p ort o f t h is co ntro ller t o s eamles sly s u ppo rt ap plicat ion lay er p ro t o co ls . In s o me cas es en ab lin g t h e A LG will allo w t h e firewall t o u s e d y n amic ep h emeral TCP/ UDP p o rt s t o co mmu n icat e wit h t h e kn o wn p ort s a p art icu lar clien t ap p licat i o n (s u ch as H.323 o r RTSP) req u ires , wit h o ut wh ich t he ad min wo u ld h av e t o o p en larg e n u mb er o f p o rt s t o accomp lis h t h e s ame s u p p o rt . Becau s e t h e A LG u n d ers t an d s t h e protocol us ed by the s pecific application that it s upports , it is a very s ecure and efficient way of introducing s upport for client applications through the controller‟s firewall. 207