traceroute pakety

[akela_at_terminal.cz at no.spam]

 Radek> Cau, potrebuju zjistit na jakych potrech vysila a prijima unix
 Radek> udp traceroute.  Nainstaloval jsem sniffit a loguju udp pakety
 Radek> ze sveho pc sniffit -F xl0 -s 10.0.0.51 -P UDP. Pak pustim
 Radek> traceroute na jakoukoliv adresu a nic neloguju. Vlastne vubec
 Radek> sniffitem nechytam vlastni pakety. Co delam spatne?  Potrebuju
 Radek> v dusledku zpruchodnit M$ ISA server pro traceroute a cvs
 Radek> pakety. Nemate negdo zkusenost???  dik Radek

AFAIK , tak se standartne v unixovych implementacich
vysle udp paket na port 33434 a dale se zvysuje cislo portu o jednicku.
 Pokud jsou porty volne nebo neblokovane tak Vam zpet prijde icmp
paket ``port unreachable'' , proto take neni dobre blokovat vsechen
icmp provoz .

U MS windows implementace traceroute je snad  delana cela pres ICMP .

PS: Stevens traceroutu venoval osmou kapitolu v TCP/IP Ilustrated 
svazek 1.


viz man traceroute 
       -p     Protocol specific. For UDP and TCP, sets  the  base
              port  number  used  in  probes  (default is 33434).
              Traceroute hopes that nothing is listening  on  UDP
              ports  base  to base + nhops - 1 at the destination
              host (so an ICMP PORT_UNREACHABLE message  will  be
              returned to terminate the route tracing).  If some-
              thing is listening on a port in the default  range,
              this  option  can  be  used  to pick an unused port
              range.

-- 
Honza Dusak
email: akela at terminal.cz