urllib/ftpwrapper

Kent Polk kent at tiamat.goathill.org
Mon May 22 21:59:41 CEST 2000


On Sat, 20 May 2000 03:10:50 GMT, Guido van Rossum wrote:
>Oleg Broytmann <phd at phd.russ.ru> writes:
>
[...] 
>>    and it hangs :( Almost all FTP URLs will hang, but there are some that
>> not: ftp://sun.med.ru/ worked (at least for me), there is pretty standard
>> wu-ftpd running there.

Speaking of ftp hangs... I have a question regarding Python servers.
Medusa/ZServer ftp server to be precise...

The problem is that since there is no seteuid in Python (presumably
because there appears to be no Posix seteuid), an ftp server
responding to an Active mode ftp client currently would have to
run as root in order to correctly service the request, as the server
has to open an outbound port 20 socket to the client.  Medusa
currently just answers the Active request using a high port number.
This appears to be incorrect and breaks most (all?) firewalled
Active Mode clients since the firewall doesn't know how to watch
for incoming ftp data port connections if they don't originate from
port 20.

What would be a suggested method to allow outgoing port 20 connections
from a Python setuid'd server such as Medusa?

Thanks



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