D-Link DWC-1000 User Manual - Page 183

Wireless Controller User Manual y o u r ISP h as as s ig n ed an IP ad d res s fo r each o f t h e co mp u t ers t h at y o u u s e, s elect Clas s ic Routing.  NA T is a t ech n iq u e wh ich allo ws s ev eral co mp u t ers o n a LA N t o s h are an In t ern et co n n ect io n . Th e co mp u t ers o n t h e LA N u s e a " p riv at e" IP ad d res s range while the Option port on the controller is configured with a s ingle " p u b lic" IP ad d ress. A lo n g wit h co n nect ion s haring , NA T als o h id es in t ern al IP ad d res ses fro m t h e co mp u t ers o n t h e In tern et . NA T is req u ired if y o u r ISP h as as s ig ned o n ly o ne IP ad d ress t o y ou . Th e co mp u t ers t h at co n n ect t h ro u g h t h e controller will need to be as s igned IP addres s es from a private s ubnet .  Tra nsp a rent ro ut i ng b et ween t h e LA N an d Op t io n d o es n o t p erfo rm NA T. Bro ad cas t an d mu lt icast p ackets t h at arriv e o n t h e LA N in t erface are s wit ch ed t o t h e Op t io n an d v ice v ers a, if t h ey d o n o t g et filt ered b y firewall o r VPN p o licies . To main t ain t h e LA N an d Op t io n in t h e s ame b ro adcast d o main s elect Tran s p aren t mo d e, wh ich allo ws b rid g in g o f t raffic fro m LA N t o Op t io n an d v ice v ers a, excep t fo r co n t ro ller -t ermin at ed t raffic an d o t h er man ag emen t t raffic . A ll DW C feat u res are s up port ed in t ran sparen t mo d e as sumin g t h e LAN an d Op t io n are co n fig u red t o b e in t h e s ame b ro ad cas t d o main .  NAT routing has a feature called "NAT Hair-pinning" that allows internal n et wo rk u s ers o n t h e LA N an d DM Z t o acces s in t ern al s erv ers (eg . an in t ern al FTP s erv er) u s in g t h eir ext ern ally -kn o wn d o main n ame. Th is is als o referred t o as "NA T lo o p b ack" s in ce LA N g en erat ed t raffi c is red irect ed t h ro u g h t h e firewall t o reach LA N s erv ers b y t h eir ext ern al n ame. 181