[squid-users] Native FTP relay: connection closes (?) after 'cannot assign requested address' error

[Alexander]

Just tried it out with REDIRECT rule. Still no luck, but now Filezilla client
reports ECONNREFUSED error. I do not see any critical errors in squid's
output, however the following thing is suspicious:

2017/01/20 19:10:11.604| 33,3| FtpServer.cc(1655) checkDataConnPost: missing
client data conn: 
2017/01/20 19:10:11.604| 33,7| FtpServer.cc(1190)
writeForwardedReplyAndCall: wait for the client to establish a data
connection

I have tcpdump'ed client's and vsftpd's interfaces and seen the following:
1. A client successfully connects to a server: squid forwards requests
properly.
2. When entering passive mode and executing the LIST command, squid opens a
data connection and receives data from vsftpd.
3. Squid opens a local port and sends it back to client via the "Entering
passive mode" reply. Seems to be ok, but a client sees a real server's IP
address, not a squid's one. So when a client tries to connect to a server,
it gets ECONNREFUSED because no-one is listening on a requested port.

Probably there means an issue with handlePasvReply(), but it's just a guess.

Taking 'wait for the client to establish a data connection' into account, it
seems that squid wants a client to connect, just to forward a data received
from a server. However a client attempts to make a direct connection and
things break down.



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