Zijici IP adresa

[uhlar na fantomas.sk]

Jan Marek <jmarek na jcu.cz> wrote:
-> traceroute IMHO pouziva pouze a jenom protokol ICMP a vytvari
-> paket tak, ze postupne zvysuje polozku TTL v paketu. Tim se mu
-> paket vraci postupne od vsech routeru na ceste se zpravou
-> "time-exceeded". Pokud ale tuhle zpravu na routeru zakazete, tak
-> se paket nevrati...

pokial viem, na icmp pakety sa reply nesmie posielat:

rfc792:

   The ICMP messages typically report errors in the processing of
   datagrams.  To avoid the infinite regress of messages about messages
   etc., no ICMP messages are sent about ICMP messages.  Also ICMP
   messages are only sent about errors in handling fragment zero of
   fragemented datagrams.  (Fragment zero has the fragment offeset equal
   zero).

Existuje sice RFC1939 (Traceroute Using an IP Option) ale je v stadiu
EXPERIMENTAL ... takze uprimne sa priznam neviem ako presne funguje
traceroute cez ICMP :(

Yo a keby ste si precitali doc k traceroute videli by ste ze sa pouziva UDP
(zrejme presne z tohoto dovodu).

-- 
 Matus "fantomas" Uhlar, sysadmin at NEXTRA, Slovakia; IRCNET admin of *.sk
 uhlar na fantomas.sk ; http://www.fantomas.sk/ ; http://www.nextra.sk/
 Fighting for peace is like fucking for virginity...

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