For 2 and a half year, I've downloaded, on average, 2-3 GB of data per day from this FTP server (astronomy data from an observatory - nothing illegal). Since Saturday I've been experiencing a weird behaviour. I use FileZilla (but see the same in all other FTP clients I've tried: command line ftp, windows ftp, WS_FTP, total commander), after downloading 3-4 files (1-2 MB each) at a regular speed (1-2MB/s) the download speed drops to 10-20 KB/s. From time to time it'll download a file at 1-2MB/s again but mostly stays at 10-20KB/s

I was wondering would the cause of such behaviour could be and how I'd go about finding out what/where the issue it.

Some facts:

  1. The FTP server is in the US (I'm in Slovakia / EU on fibre optics)
  2. Several other users in the US and EU reported slow speeds on Saturday but all now say the speed is normal
  3. Some users never saw the issue


  1. Download from other FTP servers (in the US) is normal

Things I've tried:

  1. Reinstall the client - tried passive/active connection
  2. Different clients (cmd ftp, windows ftp, WS_FTP, total commander)
  3. Reset my router to default (and disconnect the wifi router and connected the computer directly to the ISP router)
  4. Disabled the firewall (windows)
  5. Defrag my HDD
  6. Used a laptop (diff computer) on my home network

Are there any tools that could help to find out whether the issue is with my computer, home network, the ISP or the FTP server? Any proxies I could use to try to download from a "different" ip/country etc?

thank you

closed as too localized by Nifle, Indrek, Gaff, James Mertz, user3463 Sep 6 '12 at 5:18

This question is unlikely to help any future visitors; it is only relevant to a small geographic area, a specific moment in time, or an extraordinarily narrow situation that is not generally applicable to the worldwide audience of the internet. For help making this question more broadly applicable, visit the help center. If this question can be reworded to fit the rules in the help center, please edit the question.

  • Who is your ISP? – Brian Adkins Aug 31 '12 at 0:31
  • UPC Slovensko (in Slovakia) - speedtest.net/result/2150401867.png – scibuff Aug 31 '12 at 0:33
  • This is an unusual corner case of a problem that's unlikely to be experienced with other users out there. I'm telling you this, as this question may be closed as too localized and thought you might like an explanation. – James Mertz Sep 2 '12 at 17:14
  • I voted to close for being too localised, but I might suggest you speak to the FTP provider, and ask if they've instituted any throttling. Then ask your ISP. It may be a transient issue too. – user3463 Sep 6 '12 at 5:19

You may find that your ISP is traffic-shaping or throttling. Many in the UK now do this - mostly on peer-2-peer file sharing, but also for users who download large files.

If this is the case, then none of your fixes are likely to work.

  • 1
    Agreed... You're being throttled... Most likely a clause in your ISP TOS stating that they can throttle you if you use "excessive bandwidth" – Brian Adkins Aug 31 '12 at 0:30
  • thanks, I forgot to mention that download from other FTP servers (in the US) is not affected (edited it in now) – scibuff Aug 31 '12 at 0:31
  • p.s. even if that was the case, are there any diagnostic tools I could run to confirm that the ISP is throttling the download (although I find that improbable since FTP download from other servers works at 1-2 MB/s - as per my edit) – scibuff Aug 31 '12 at 0:41
  • 1
    If your ISP isn't throttling you, the FTP server is. Nothing else would explain this behavior. – Dennis Aug 31 '12 at 2:55

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