Friday, June 15, 2007

Active FTP vs Passive FTP

wooooow ... yup ...spend almost a day testing active FTP and passive FTP through a firewall , what was interesting is not the firewall but the "active and passive FTP"

tools :
Fedora core 6 - FTP server
Fedora core 4 - FTP client

I actually tried to use Windows client but could not find the command to disable "passive mode FTP " ...but I found one artical about how to disable passve FTP in internet explorer
suprizingling I found a bug in Fedora Core 4 - when the FTP client send "PORT" command or "Passive" comand etc the pkt sent has a check sum error - in the TCP section !!!

the first problem I faced - how can I initiate an Active FTP session because all FTP clients use passive FTP by default !!! .... after lot of search I figuredout that its not that difficult ,

open linux shell , tupe "ftp" and then type "passive" - then u will see the message "passive mode is off"
shell> ftp
ftp> passive
Passive mode off

then just use get command to download some file !!! u have ur self an ACTIVE FTP connetion !!!
ftp> get test.txt

and use "etheral to capture pkts " ... then u can see for sure that it was an Active FTP session !!!

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