constant 421 errors after upgrade to 3.38.1

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ixaxi
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constant 421 errors after upgrade to 3.38.1

#1 Post by ixaxi » 2018-11-14 01:32

Since upgrading to 3.38.1 I suddenly get 421 errors (too many connections (40) on all account and all servers I connect to. When uploading a few hundred files go fine, then suddenly connections seem to jam. I've set a maximum number of connections (never did that before!), 10, then 8, then 7, same thing happens regardless. Tried switching to plain unsecured ftp, same thing happens. I did contact the hosting firm, they suggest connections aren't closed properly which racks up the number of connections, even when limited in the settings (they say they allow 8).

Before the upgrade I could easily upload 10s of thousands of files, uninterrupted, never had 421 before. All help greatly appreciated!

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Re: constant 421 errors after upgrade to 3.38.1

#2 Post by botg » 2018-11-14 09:12

Stale connections like this are always the result of a faulty firewall or NAT router silently dropping connections without informing both peers of this evil deed.

ixaxi
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Re: constant 421 errors after upgrade to 3.38.1

#3 Post by ixaxi » 2018-11-15 14:58

Thanks for your answer.. but.. I don't have a firewall.. I'm on a MacBook Pro, and have used the same router for a few years now.

It seems significant to me that these stale connections never happened before.. So same equipment, same set-up, the only change is that I upgraded to Filezilla 3.38.1 and then all of a sudden this 421 problem appeared? So does 3.38.1 maybe 'talk' to my router in a slightly different way, causing this lack of peer-informing?

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Re: constant 421 errors after upgrade to 3.38.1

#4 Post by botg » 2018-11-15 19:27

The networking code hasn't changed in 3.38.1

Could your server provider run a firewall? Could your ISP run a firewall? Could the server provider's ISP run a firewall?

ixaxi
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Re: constant 421 errors after upgrade to 3.38.1

#5 Post by ixaxi » 2018-11-19 11:36

Tim, many thanks again for your suggestions..

Before I wrote here I did contact my hosting people, they told me there are no restrictions (they allow 8 simultaneous connections, but said this usually doesn't have to be set in the FTP agent). They may well have a firewall in place, but they didn't make any changes any time recent. They looked into their logs and told me the agent doing the FTP (i.e. FileZilla) is not closing the connections properly and suggested I contact you..

Whether my ISP has a firewall I wouldn't know, how can I find out?

Sorry to keep banging on about it, but my (working) life depends on this quite a bit, I regularly transfer entire sites (around 30 to 40.000 thousand files at a pop), and suddenly this takes me hours, especially as I can't switch it on and walk off, I now have to watch it, after each 500-1000 files it suddenly freezes, I need to stop transfer, wait several minutes (or close each open connection in panel on the server one by one) and then resume..

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Re: constant 421 errors after upgrade to 3.38.1

#6 Post by klobber » 2018-11-19 17:08

I'm sorry for borrowing your thread, but I have a simple question regarding this problem, possibly a bit stupid one.

When downloading or uploading large amounts of files I constantly get disconnected and reconnected, like so:
filezilla-421-too-many-connections-from-this-ip.png
filezilla-421-too-many-connections-from-this-ip.png (5.87 KiB) Viewed 163 times
Is there any possibility that this could cause some files not getting downloaded / uploaded? I don't mind this issue if the files still get transferred 100%.

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Re: constant 421 errors after upgrade to 3.38.1

#7 Post by botg » 2018-11-20 08:28

If it happens several times in a row on the same file that file transfer can fail, upon which the file is added to the failed transfers queue tab.

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