Intermittent Delay Before Download of Attachment Starts

[archiebald]

I'm running SMF 2.07 on a dedicated Windows 2003 Server.  We use this forum to share documents within our company including various MSOffice files, video, photo etc. ranging from 1-2MB up to 200MB.

In the last week or two (with no recent updates or mods from my side) I noticed that when clicking on an attachment link, there is sometimes a delay of anything up to several minutes before the browser dialog box pops up.  I say sometimes, because on other occasions, the pop-up is almost instant (as it used to be). 

When there is a time delay it seems to be dependent on file size and most interestingly when there is a long delay, and after I eventually click "Save As..." the download completes almost instantly meaning that it must have been sitting there downloading in the background but not letting the browser dialog box pop up.

I am not running compression on the server and there is plenty of space on the hard disk.  Also, I am not doing any caching or acceleration.

Tried it in Firefox, Chrome and IE with similar results in all three.

I have been running this forum on the same server for several years with gradual updates, but this is the first time to see this issue.  Any suggestions would be gratefully received.

[Ninja ZX-10RR]

Well first things first. Try to upgrade to SMF 2.0.8 that contains some memory-related bug fixes

[archiebald]

Thanks for the heads up on this update, installed and tested but it makes no difference whatsoever to the problem.

[Ninja ZX-10RR]

Have you tried Admin-->Maintenance-->Forum Maintenance-->Routine-->Find and repair any errors?
It's really weird to me I never heard anything similar before..

[archiebald]

Just tried that, no errors reported.

[archiebald]

Just a small piece of additional information.  While the delay is occurring, the "Connecting" message and time counting dial is displayed on the browser tab, and in Firefox at least, there is a message in the bottom left of the window, "waiting for xxxxxx.com" as if the browser is waiting for something from the forum.

[Ninja ZX-10RR]

Sounds more like an issue with your host but hmm... I don't know if I can be of any help with this as I have never read anything about such an issue.. But is your error log clear? And your php error log on the database as well?

[archiebald]

Thanks for your ideas.

This is on a dedicated server, it is running PHP 5, but I can't remember the version right now without checking as it has been so long since there have been any issues.  I will need to check the logs.

One other point that may or may not be related, I often access this server using Windows RDP and recently came across this issue for the first time.
http://social.technet.microsoft.com/Forums/en-US/31b681c5-3658-45a5-8158-a0a0f967c4a2/rdp-screen-goes-black-after-successful-remote-login

I have now overcome the RDP issue, but this is also the first time to see this as well and I don't like coincidences.

I am connecting from my office now, so I will attempt to make the same tests from my home over the weekend just in case it our company network security throwing a spanner in the works.

[Ninja ZX-10RR]

Ok here I step aside and follow, I am pretty sure that someone with more experience in this field will help because I have never treated this before and I don't want to tell you or suggest something I don't know myself. Wait a bit and sorry if I can't assist you better with this issue.
*follows the topic in silence, extremely curious and hurt in his proud*

[Dragooon]

How big are the attachments which cause the delay?

[archiebald]

How big are the attachments which cause the delay?

The attachments vary in size from a few KB up to a maximum of 300MB.  The delay issue has two variations;
1. In some cases there is NO DELAY and the dialog box comes up instantaneously (as it always used to).  These cases might be a very large file or a very small file, it seems to be totally random.
2. In other cases the dialog box appearance is delayed proportionally to the size of the file so the delay can be anything from a few seconds to several minutes.  In every case where a delay occurs in the dialog box appearing, when I click the "Save" button, the download happens almost instantly, so it is obvious that during this delay period, the data is actually downloading to my browser cache.  Problem is that users will obviously think the browser is frozen during the delay periods.

The proportion of case 1 and case 2 occurrences seems to be around 50:50 as far as I can tell.

What I can't fathom out is why the delay is suddenly occurring, and why it is random.

[Dragooon]

Go to Server Settings, is compressed output enabled? Can you try disabling it?

[Kindred]

is it a specific TYPE of file that is causing the delay (e.g. only word DOCs)?
Is it only happening on one specific browser>
Have you tried on a different browser?


What I suspect changed was the browser...

You get a browser update (maybe even unknown, depending on your IT protocols), and now it tries to parse/load the file that it is downloading. before generating the dialogue box...

[Ninja ZX-10RR]

is it a specific TYPE of file that is causing the delay (e.g. only word DOCs)?
Is it only happening on one specific browser>
Have you tried on a different browser?


What I suspect changed was the browser...

You get a browser update (maybe even unknown, depending on your IT protocols), and now it tries to parse/load the file that it is downloading. before generating the dialogue box...

Tried it in Firefox, Chrome and IE with similar results in all three.

That's why I didn't say that and claimed I have no idea on how to solve this.

[archiebald]

is it a specific TYPE of file that is causing the delay (e.g. only word DOCs)?
Is it only happening on one specific browser>
Have you tried on a different browser?


What I suspect changed was the browser...

You get a browser update (maybe even unknown, depending on your IT protocols), and now it tries to parse/load the file that it is downloading. before generating the dialogue box...

No, not a specific file type or size.
It is happening exactly the same in Chrome, Firefox and IE

Browser has not changed.

However, I managed to do some more testing and found as follows.  Using my home network, there is no issue, and I also set my notebook to tether to a wireless hot spot set up on my smartphone.  Using the phone carrier's network the problem has seemingly disappeared.  Switching back to my company LAN or WIFI makes the problem very repeatable.

So, I would judge for now that it is NOT an SMF problem, more likely some security protocol that our useless IT department has invoked.

I will mark this topic as solved for now but if some significant find is made, I will report it back here in case it might help someone else.

[archiebald]

I finally got a report from our IT department that the problem was due to a firewall setting on our company network.  Changes have been made and the problem seems to have gone away.  No details yet but I will try to push for more info.

[Ninja ZX-10RR]

If that IT stands for Italian I feel ashamed for being Italian
Tell us anyway if you can provide further details, they could be useful even if this case is mosre unique than strange.

[margarett]

No, it's IT like "Information Technology"

[archiebald]

Actually in our company (and I suspect many others), it is more like "Irritating Tossers".

I am actually in Japan and one thing I have learned over the years is that Japanese software is some of the most clunky and user unfriendly in the world and that attitude filters into their IT people.  I have now requested "exact details" twice but so far their best effort was "something in the firewall was changed", I have stepped up the pressure to the next level so I will wait for them to try another answer.

[Ninja ZX-10RR]

Good to read both of your answers XD