Maximum simultaneous connections set too high

[Guest]

As a developer of web-mapping sites, we have frequently running into the
problem of images appearing broken in Internet Explorer. The image url is
valid, and shows up correctly in other browsers. Also, not all computers with
internet explorer would suffer from it. There also appears to be little
relation to bandwidth. However, the problem has seriously affected our
ability to deploy websites with many objects in them, as is typically the
case with web-mapping.

Today I found out that the cause seems to be the amount of requests sent by
internet explorer (MaxConnectionsPerServer and MaxConnectionsPer1_0Server).
In this article (http://support.microsoft.com/?kbid=282402) it is said that
the default value for maximum connections to one server is 2. However, our
computers appear to have a value of 10,000. In some cases, it has even caused
serious instability on our server. After lowering this value of about 5, all
problems went away.

My question is, where did the value of 10,000 come from? Can anything be
done to prevent the value from being made this high by external applications?
I see no practical benefit to this value being higher than, say, 20. I have
seen *many* computers suffering from this problem, making me think that the
default value may not be 2 at all.

 

[Vanguard]

As a developer of web-mapping sites, we have frequently running into the
problem of images appearing broken in Internet Explorer. The image url is
valid, and shows up correctly in other browsers. Also, not all computers
with
internet explorer would suffer from it. There also appears to be little
relation to bandwidth. However, the problem has seriously affected our
ability to deploy websites with many objects in them, as is typically the
case with web-mapping.

Today I found out that the cause seems to be the amount of requests sent
by
internet explorer (MaxConnectionsPerServer and
MaxConnectionsPer1_0Server).
In this article (http://support.microsoft.com/?kbid=282402) it is said
that
the default value for maximum connections to one server is 2. However, our
computers appear to have a value of 10,000. In some cases, it has even
caused
serious instability on our server. After lowering this value of about 5,
all
problems went away.

My question is, where did the value of 10,000 come from? Can anything be
done to prevent the value from being made this high by external
applications?
I see no practical benefit to this value being higher than, say, 20. I
have
seen *many* computers suffering from this problem, making me think that
the
default value may not be 2 at all.

I have never had this value changed unless it was me that went into the
registry to edit it. There are probably 3rd party tweak apps, like X-Setup,
that can edit the key, too (i.e., instead of using regedit.exe, you use some
other program to do the registry editing). I suspect you had a user or
admin that tweaked the setting that got pushed out when multiple desktops
were prepped using the same image.

 

[Charlie Tame]

Phew, no wonder it went unstable

Do you think there is any possibility of malware or some trojan having done
this in the past? I do not know of anything that does but I am thinking of
something that could be used to download stuff (say porn) onto your servers
by some of these dubious professional sites. I guess you might consider
badly written "Download managers" too. You know, more threads but throttled
so nobody notices? Also I wonder if any Peer to peer sharing systems might
use this? Again, pure speculation, I cannot see why they would, but who
knows, there's lots of inventive people out there. Anyway, just to add that
the value has always been 2 on systems I have seen so I don't see it being a
bug inflicted by default or by an update... and I believe the RFC states two
maximum and MS would never do anything that wasn't in an RFC now, would
they?

Charlie

 

[Guest]

Thanks for the reply. I have noticed this is the default value in most
Windows XPs installations I have looked at; not just prepped/imaged versions.

 

[Vanguard]

Thanks for the reply. I have noticed this is the default value in most
Windows XPs installations I have looked at; not just prepped/imaged
versions.

And out of just over 50 setups done in our alpha test lab or on our
desktops, I've never found it to be different than the default. Maybe the
CD used for installation is a bastardized OEM version for some specific
vendor rather than the generic Microsoft version. Could be all those
installations also installed common software so it one of those that
"tweaked" the settings.

The KB article you mentioned specifies what is the Microsoft established
default that they use for Windows. Anything else is not the Microsoft
default but someone else's.

 

[Daniel Crichton]

I've checked all of my XP machines here at work, and my home XP machines,
and none of them have these settings. Could it be possible that your XP
machines have been setup from a slipstreamed install CD that someone has
added these settings to?

Dan

Nic wrote on Mon, 9 Jan 2006 00:19:03 -0800:

 

[Charlie Tame]

Do you get updates from MS or are they downloaded to your servers and then
distributed. Just wondering if something got in there that's faulty in some
way and maybe that would explain why it's spread?

Also I suppose there may be a way to adjust this in group policy... perhaps
you might post a question in the GP groups in case someone has seen this
before.

I honestly can't see any sensible reason even for hackers to do this so I
think it must be an error, perhaps intended for another registry key and
they simply typed the wrong one or the wrong value in the right key

Charlie