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Re: FTP connections

by jeffenstein (Monk)
on Feb 21, 2002 at 15:04 UTC ( #146768=note: print w/replies, xml ) Need Help??

in reply to (Kozz) Re: "canned" FTP
in thread "canned" FTP

Passive mode ftp still uses a second connection for data, just the direction of the connection differs.

In normal 'active' ftp, the client connect to remote port 21 for control, and data connections come back from the server with a source port of 20 and destination port > 1024. In 'passive' ftp, the client still connect to remote port 21 for control, however data connections originate _from_ the client on a port > 1024 to the remote server on a port > 1024, thus passing through firewalls that only allow outgoing connections.

Then, of course, is the issue of binary mode encoding, translating between formats, etc... Much easier to use Net::FTP, unless you have a week or so to kill on a 15 minute job. ;-)

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[marto]: X86_instruction_li stings
[marto]: Illegal_opcode
[zentara]: marto arn't those NSA secrets? :-)
[marto]: not if you keep telling people :P
[zentara]: I had to disable hyperthreading on my machine because of that.
[Discipulus]: thanks marto but... at the moment this seems a bit beyond my faculties.. ;=)
[zentara]: a thread goes into a wait state after emitting a wait to all other threads. It locks up a machine completely.
[marto]: if you mean the recent hyperthreading bug, I don't think that's NSA related?
[zentara]: s/thread/cpu/
[marto]: xkcd://538

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