Win XP SP2 will limit your maximum connections

[prathapml]

besides talk of bringing home new donkeys to test something.....

@gamehead-

See if ShareAza is able to connect to the Gnutella1 network (or atleast is able to contact peers to request a connect). If not, then you have some firewall at your end blocking it from connecting outwards - Windows Firewall works fine, ZoneAlarm not.

Using eMule or BitTorrent clients is just as well too! That would also serve the same purpose. Basically, we want to run an app which swiftly raises the number of requests for outward open TCP connections - and then see (through event viewer) if that has been blocked.

[Toonz]

What setting are you guys using for the Windows Firewall for eMule, etc? When I open up tcp 4662 and udp 4672 for use in emule i still get HEAPS of dropped connections.

???

Thanks guys,

[gamehead200]

Gnutella 1 and 2 connect fine, its just eDonkey that doesn't connect...

[prathapml]

Gnutella 1 and 2 connect fine, its just eDonkey that doesn't connect...

OK, that's fine - sufficient.

Now try downloading something (umm.... something popular which lots of people have shared - ah, why not download XP SP2 itself) for 5 minutes. By this time, the needed results have come. Stop the download and check for EventID 4226 (hopefully that hadn't appeared ).

[gamehead200]

Seems to be connected now... Got an updated server list and it connects... I guess that was the problem! Nothing in the event logs!

[prathapml]

OK, that's cool then!

I suppose we know what that means (unless your logs were lying or your eyes didn't search properly) - it was successful.

[gamehead200]

OK, that's cool then!

I suppose we know what that means (unless your logs were lying or your eyes didn't search properly) - it was successful.

My logs got corrupted somehow, so I saved a copy, and cleared it, so now I'm waiting to see what will happen in the next few days...

[gabriel_buc]

I read the entire thread, but I'm confused ....

Which is the link to the patched tcpip.sys file with UNLIMITED connections for SP2 FINAL RTM 2180 ?

EDIT: Nevermind I found the right file. I even verified if it's the correct one and if it's properly hexedited.

[BAM]

@prathapml:

Thnx for youre very nice answer!

It took so long before i got any answer.

I will test it tonight after the last few adjustments i want for my unattend sp2.

Thnx alot.

[dirtyepic]

Hey guys, i just wanted to point something out. SP2's TCPIP.SYS limits the maximum half-open connections made PER SECOND. So yes, you can have 400 connections open in EMule, and yes BT programs let you have 100 or more connections per torrent or 1000 globally by default. That's the number of concurrent (total) connections you can have and that is the number that is controlled by the registry key on the first page of the post. These numbers are not related in any way.

A half-open connection means a connection that is open on your end but doesn't nessessarily have to be connected by another peer, so like opening a listening port that has nothing coming in yet, or requesting a connection to another machine but not established yet. Anyways, you get 10 of these per second under SP2. That's admittedly pretty low for BT or any p2p sharing prog where you can connect to say 200 people within a couple seconds time. But, what happens when you manage to hit this limit for whatever reason is the TCP/IP stack goes into a flood control kind of mode, and queues pending connections and processes them at the rate set by Max Connects per Second (ie. 10, or 50 if you've patched).

Now, if you consider that for a second (or 10 connections), it's pretty rare that any application you're running needs to establish a huge amount of connections for any considerable length of time. Usually it's a burst of connection activity - when you start a torrent or download a whatever you crazy eMule people call it - and once they're established there's a pretty big dropoff. So, basically the only way this setting is even affecting you is it takes a few more seconds than usual to establish connections when there's a lot of TCP/IP activity.

That's it.

In fact, in Azureus there's a feature, "Slowly connect new peers", and it does the exact same thing as this TCP/IP stack change does, altho i'm not sure of the rate. This isn't unique to Azureus, it's a concept that's been around for a long time - look at mIRC flood control, it's the same thing. The point is, because mass-opening connections is an effective way to make an OS scream like a little girl, many programs that have the ability to do so already have built-in traffic control you've just never noticed.

Seriously, the only thing that will be hindered by this change is software that opens a very large amount of new connections in a very short amount of time, for a very long amount of time. i think that made sense. you get what i mean. other than port scanners and malware/worms, i can't think of anything else that would require more than 10 (or 50) connections per second for any reasonably large period of time. (there very well may be legit programs that do, i just can't think of any).

Sorry bout the long post. One of my biggest annoyances is misinformation. Thanks for your time and please try to spread the word.

[neophyte]

dirtyepic: I think they're all getting their p*****s in a knot because they don't like having what they can do with their computer dictated to them by Microsoft (which is fair enough).

Anyway, your thread is quite true and valid.

I personally would have preferred MS to have set it to something a little more reasonable, such as 50 (*cough* the hack *cough*), but meh.

Anyway, I won't be applying the patch, because I don't really care about it that much.

Edited August 12, 2004 by prathapml

[prathapml]

@dirtyepic

Thanx for clearing that up!

Nice of you to take the time to explain it properly - long informative posts never were a problem.

Though we already knew most of it by now, the level of detail in your post has been enlightening.

[Denney]

Thanks dirtyepic for the information but now I'm really confused.

Ever since I joined the beta test of SP2, Azureus and eMule have decreased significantly in the speed at which they download and the number of connections that actually make.

When I apply the registry tweak, nothing really changed, but once I started using this tcpip.sys file as well, speeds and connections have shot straight back up.

Now, if, as you say, this connection limiting should have no effect, what else could be causing the low speed and number of connections? I'm not calling you a liar or anything, I'm just curious as to what else could have been causing the problem.

The only 2 things I changed about my setup was that registry key and the tcpip.sys file. But the registry key alone doesn't make a difference.

Weird...

[dirtyepic]

no, to be honest i have also heard of improvements in Azureus after applying the patch to raise it to 50 connections, but people are very suseptible to the power of suggestion so you have to take things like this with a grain of salt (i still see ppl who swear by the QoS 20% "tweak" even though it's been disproven by just about everybody).

but there still may be a valid reasoning behind the claim. bittorrent has a choking/unchoking algorhythm that evaluates and switches peers every 10 seconds to keep speeds optimal, so it could be possible that when you take a situation with 10 or 20 torrents there may be an effect caused by this change. i don't know anything about the emule/donkey/overnet protocol so i won't say anything. i haven't noticed such an improvement myself but i haven't done any serious testing.

so i may have been too hasty to completely dismiss it. i do feel that MS set it a bit too low, and i support patching it to 50/s. changing it back to unlimited, however, i think is a bit overkill and a bit counter-productive because it is, in theory, really not a bad idea. i think they should have made it user-editable to begin with, but i have a feeling the reason they didn't is because they didn't want another reg entry that everyone just turns off anyways.

[fungun_007]

Thanks Zaheer, great job