An xrhsimopoieite ena H/Y Linux me duo kartes diktuoy gia na dromologeite metaju duo (h perissoterwn)ypodiktuwn, xreiazetai na exete energopoihsei thn Prow8hsh IP (IP Forwarding) ston pyrhna sas. Kante ena
cat /proc/ksyms | grep ip_forward
8a prepei na sas epistrecei kati san...
00141364 ip_forward_Rf71ac834
An oxi, tote den exete energopoihsei thn Prow8hsh IP (IP-Forwarding) ston pyrhna sas kai xreiazetai na epanametaglwtissete kai na egkatasthsete enan neo.
Gia xarh toy paradeigmatos, as ypo8esoyme pws exete apofasisei na ypodiktywsete ton C klashs ari8mo diktuoy sas 192.168.1.0 se 4 ypodiktya (to ka8ena apo 62 xrhsimopoihsimoys interface/host ari8mous IP). Parola ayta, duo apo ayta ta diktya syndyazontai se ena megalutero eniaia diktyo, dinontas tria fysika diktya.
ayta einai :-
Network Broadcast Netmask Hosts 192.168.1.0 192.168.1.63 255.255.255.192 62 192.168.1.64 192.168.1.127 255.255.255.192 62 182.168.1.128 192.168.1.255 255.255.255.126 124 (des shmeiwsh)
Shmeiwsh: o logos poy to teleytaio diktyo exei mono 124 xrhsimopoihsimes diey8unseis diktuoy (oxi 126 opws 8a perimename apo th maska diktuoy) einai giati sthn pragmatikothta einai ena 'yper-diktyo' duo ypodiktuwn. Oi Host sta alla duo diktya 8a metafrazoyn to 192.168.1.192 san th diktyakh dieu8ynsh toy 'mh-yparktou' ypodiktuoy. Paromoia, 8a metafrazoyn to 192.168.1.191 san th dieu8ynsh ekpomphs/anakoinwshs toy 'mh-yparktou' ypodiktuoy.
Etsi, an xrhsimopoieite to 192.168.1.191 h to 192 san host diey8unseis toy tritoy diktuoy, tote oi mhxanes twn duo mikroterwn ypodiktuwn den 8a einai ikanes na epikoinwnoun mazi toys.
Ayto katadeiknuei ena shmantiko 8ema me ta ypodiktya - oi xrhsimopoihsimes diey8unseis ka8orizontai apo to MIKROTERO ypodiktyo ston xwro diey8unsewn sas.
As ypo8esoyme oti enas ypologisths poy trexei Linux dra san router gia ayto to diktyo. 8a exei tria interface diktuoy sta topika LANs kai pi8anon ena tetarto interface sto Internet (poy 8a apotelei kai thn proka8orismenh toy dromologhsh).
As ypo8esoyme oti to Linux xrhsimopoiei thn xamhloterh dia8esimh dieu8ynsh IP se ka8e ypodiktyo sto antistoixo interface gia to diktyo ayto. 8a ru8mize ta diktyaka toy interface ws:
Interface IP Address Netmask eth0 192.168.1.1 255.255.255.192 eth1 192.168.1.65 255.255.255.192 eth2 192.168.1.129 255.255.255.128
H dromologhsh poy 8a egka8idrye 8a htan:
Destination Gateway Genmask Interface 192.168.1.0 0.0.0.0 255.255.255.192 eth0 192.168.1.64 0.0.0.0 255.255.255.192 eth1 192.168.1.128 0.0.0.0 255.255.255.128 eth2
Se ka8'ena apo ta ypodiktya, oi host 8a ry8mizontan me to proswpiko toys ari8mo IP kai maska diktuoy (katallhlh gia to sygkekrimeno diktyo). Ka8e host 8a dhlwne to Linux PC ws th dikia toy pulh/dromologhth (gateway/router), 8etontas thn dieu8ynsh IP toy interface toy Linux gi'ayto to sygkekrimeno diktyo.
Gia sxolia, parathrhseis, dior8wseis, enhmerwseis peri ths Ellhnikhs metafrashs aytou toy HOWTO, steilte email sthn Boula Sanida : voulariba@hellug.gr h ston Eyripidh Papakwsta : evris@hellug.gr kai enallaktika : ep@rocketmail.com
Robert Hart Melbournh, Aystralia Martios 1997.