Merikes dieukriniseis parakalo!

[Filippos Slavik]

On Thursday 24 February 2005 21:28, Richard Anderson wrote:
> Den einai akrivos linux erotiseis alla i have to ask them so to
> understand:
>
> 1) Episis DEN exo vgalei akri genikos! An den orisoume sto configuration
> utility tou adsl modem/router poia mac address tha parei poia specific ip
> address tote einai san na leme tou adsl modem/router oti kathe fora pou
> einai na apodosei ip addresses na apodidei opoia ip address thelei se
> opoia NIC thelei ,diladi opoia ip address thelei se opoio pc goustarei
> apo auta pou einai connected pano tou! Auto omos DEN mou fainetai kai
> toso kalo. Den tha eprepe to kathe pc sto lan na exei mia sygekrimeni
> static ip address i opoia tha ginentai kathe fora applied stin Nic tou?

Kai to ena alla kai to allo boleuei. Se kapoies periptwseis 8eleis na dineis 
IPs apo kapoio pool se hosts xwris na eksetazeis poia h MAC tous, allwte 
8eleis na dineis sygkekrimenes IPs se sygkekrimenes MAC, allwte 8eleis na 
dineis IP mono se hosts pou gnwrizeis ths MAC tous, klp, klp. 

>
> 2) Sto Cleint Ip Pool Starting Address giati xekinate oloi vazontas
> 192.168.1.x kai oxi kapoia alla tyxeia noumera. Starting address legetai
> giati auto pairnetai os vasi gia na
> arxisei kai na synexistei i onomatodosia ton ip address?

Yparxoun merikes IP oi opoies legontai reserved kai xrhshmopoiountai gia 
internal dyktia ta opoia den einai routable apek'sw. To C class network (des 
http://www.webopedia.com/TERM/C/Class_C_network.html) 192.168.1.0 einai ena 
apo ta poio xarakthristika pou xrhshmopoiountai gia tetoious logous (yparxoun 
kai alla bebaia).

8a mporouses na baleis esy sto eswteriko sou dyktio opoio "starting address" 
8eleis, alla einai pi8anon na exeis problhma. Px mporeis na baleis to 
194.63.247.0, alla kapoio mhxanhma sto eswteriko sou dyktio einai pi8ano na 
parei apo ton router (apo to DHCP daemon basika) thn 194.63.247.208 
(www.in.gr). Auto katalabaineis thn problhma dhmiourgei profanws sto 
eswteriko sou dyktio -> den mporeis na bgeis pros to dyktio 194.63.247.0 (to 
opoio einai kapou sto real internet) .. kai gia na sto poio praktika, kapoios 
sto eswteriko sou dyktio 8a prospa8hsei na anoiksei thn selida tou www.in.gr 
kai 8a epikoinwnhsei telika me kapoio allo mhxanhma sto eswteriko sou diktuo.

>
> 3) Akoma den katalava ti paizei me to NAT, se ti akrivos xreiazetai
> akthos kai gia to Port Forwarding.....

NAT -> http://www.webopedia.com/TERM/N/NAT.html kai sigoura polla alla 
resources sto dyktio gia na katalabeis ti einai auto. Praktika auto shmainei 
gia sena: Exeis ena local dyktio (pisw to apo to adsl routeraki sou gia 
paradeigma) me IPs apo to 192.168.1.0/24. To adsl routeraki sou otan 
syndeetai sto dyktio apokta mia IP (h opoia einai pragmatiki) kai einai 
routable pros kai apo ton kosmo (to internet). Auto pou kanei twra to NAT 
einai oti ka8e paketo pou er8ei apo kapoio host apo to eswteriko sou kai 
8elei na bgei pros ta eksw, "allazei" ligo kai bgainei pros ta eksw me thn IP 
tou router/adsl (opote einai valid gia na ginei route). To routeraki 
"8ymatai" poianou host apo to eswteriko dyktio htan to paketo pou molis ekane 
forward ston eksw kosmo kai otan er8ei h apanthsh apo ton eksw kosmo (px h 
html selida pou zhthses [xarhn aplwthtas twra]) tote to paketo auto ginetai 
forwared sto host tou eswterikou sou dyktiou. Auto legetai kai SNAT (Source 
NAT). To port forwarding einai na exeis thn dynatotha na kaneis mapping kai 
na les kati sto styl "otan erxetai ena paketo apo ton eksw kosmo sthn IP tou 
adsl/router kai se kapoio port tote auto to paketo na ginetai forwarded sto 
host x kai port y tou eswterikou sou diktiou. Auto praktika shmanei pws 
mporeis na exeis ena host sto eswteriko sou diktio pou na trexei enan apache 
kai na einai "visible" pros ton eksw kosmo (kati pou den 8a htan efikto an 
den eixes NAT & Port forwarding).

>
> Sorry again pou oi erotisiseis den einai linux oriented alla tha prepei
> kapoia stigmi na ta ksekathariso auta.....

Yparxoun pantws polla resources & howtos pou mporeis na diabazeis gia ta 
pramata pou rwtas se poly kalyterh diatypwmenh morfh apo'ti sta lew egw 
(allwste egw sou apantaw praktika) kai se non-formal yfos.

Slavikos

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Filippos Slavik, FORTHnet R&D, Heraklion, Greece
e-mail : fsla at forthnet.gr, phone : (+30) 2811 391230

"The software said 'runs on Win95 or better,' so I installed it
on Linux..."

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