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problem with the FTPS connection, Error code 421

Posted: 2021-01-27 01:44
by ad20201216
I am having a problem with the FTPS connection. Details are as follows:
server OS:Windows Server 2012 R2
server :Filezilla 0.9.43 beta
client OS:Windows 7
I use apache commons net 3.7.2 as base lib,and extend FTPSclient,my code as follow:
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and i get client error
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filezilla server's error log:
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error id is 004056
This error occur randomly, and may occur after a few connections or dozens of connections.

Re: problem with the FTPS connection, Error code 421

Posted: 2021-01-27 01:52
by boco
You are using an unsupported version of FileZilla Server. Please update to 0.9.60.2 as it's the only one supported.

Re: problem with the FTPS connection, Error code 421

Posted: 2021-01-28 01:54
by ad20201216
thanks for u reply,but I can't upgrade the version of filezilla in production environment.

Re: problem with the FTPS connection, Error code 421

Posted: 2021-01-28 10:32
by botg
Rant: I'm seriously considering to add a killswitch to all my products so that they _HAVE_ to be updated regularly...

Re: problem with the FTPS connection, Error code 421

Posted: 2021-01-29 03:23
by boco
ad20201216 wrote:
2021-01-28 01:54
thanks for u reply,but I can't upgrade the version of filezilla in production environment.
Your "production environment" is in grave danger. That ancient version contains multiple severe security vulnerabilities actively being exploited in the wild. Additionally, no one here really knows anymore how that version worked and behaved, as we moved on.
For your own good, you really need to come up with a concept for doing proper server maintenance. Most simply, run a backup server to keep production up while upgrading. Or, prepare a fully updated FTP server with identical configuration, test it on a spare machine, then, do an in-place switch. Easy to do with FileZilla Server and keeps downtime short.
botg wrote:Rant: I'm seriously considering to add a killswitch to all my products so that they _HAVE_ to be updated regularly...
Good idea. You can't keep users from running old versions, as it's Open Source Software, after all. But those forks will not get any support here, as the GPL license states.

Re: problem with the FTPS connection, Error code 421

Posted: 2021-03-23 10:07
by ad20201216
3q for ur advice! I'll try it.