[SOLVED] Changed MTU value, and now none of torrents work.

Mariusglock

Commendable
Jun 13, 2020
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Hi forum,

I was curious if it would actually increase or decrease my bandwitdh speed. I've changed my MTU value fallowing this tutorial:
View: https://www.youtube.com/watch?v=RK2PHpKI9M4&list=LL&index=17&t=312s&ab_channel=LironSegev

After changing it, to no surprise speed did not change, and stayd the same.

However, while everything worked as normal, my torrents just stopped working.
I've changed the MTU value back to what it was, but that made no difference.

No torrents can be downloaded anymore, are all in a "stalled" state. Tried diferent torrent clients, uninstalling and reinstalling them a few times, tried most popular torrents with plenty of seeds, even the ACE stream stopped working for streaming movies directly from torrents.

The change was made only on my PC and not on modem.

Its weird that only torrents doesnt work, while everything else, youtube, hbo, netflix, any website, online games, works as normal.


PC specs: https://nl.pcpartpicker.com/list/sCQj8J
Internet connected via internal motherboards LAN connection.
Can't give you my modem info, since its being used by several households, and is out of reach. (But no one has access info, apart from landlord, so no one could have changed anything there)

Any idea how to fix this?
 
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Have you tried reinstalling windows. It seems you were using magic tools to change stuff rather than making setting changes by hand one at a time. It is pretty easy to undo a change when you only make 1 but when you use tools you do not fully understand you can make a mess.

Anyone who say you can adjust the MTU on the internet is a fool. First part of the session initiation that takes place will determine the largest mtu that can be used. It can be slightly different if you for example run a vpn that adds overhead to packets.
You can not increase the mtu over the common default value of 1500....and even then it most times uses stuff like 1460. You must in full control of every hop in the path to be able to increase the MTU. It is something that is done in data centers for disk networks it is not something you do over the internet. You also tend to need very specialized equipment because most consumer router and switches do not support larger MTU.

People really should stop listening to people on youtube. It would be very rare you find someone qualified. Almost everyone is some kind of entertainer or journalist first. Nobody with actual network/computer skills is going to waste their time on youtube when you make more money actually doing the job. It is almost always people that do not have the skills to get a real job in IT that you find on youtube.
 

Mariusglock

Commendable
Jun 13, 2020
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Where is the router? Who has control of the router? Landlord?

If so, the landlord is the only person who can help.
I've got the cable runing straight from the modem, to my PC. However nothing was changed on the modem it self( since no one has log-in info for the modem), I only changed the settings on my PC's OS(win10) itself.
 

Ralston18

Titan
Moderator
Then you will certainly need the landlord's assistance.

For most small networks the connectivity is:

ISP ----> Modem ----->Router -----> Ethernet cable to wired devices (such as the cable to your PC) and ~~~~> Wireless to wireless devices.

Depending on the make and model modem (more likely a combined modem/router if there is only one physical device) there may or may not be logs available.

Therefore the landlord will need to check the modem/router's logs (again, if available and enabled) for any related errors.

Have you discussed the problem with the landlord?
 
Have you tried reinstalling windows. It seems you were using magic tools to change stuff rather than making setting changes by hand one at a time. It is pretty easy to undo a change when you only make 1 but when you use tools you do not fully understand you can make a mess.

Anyone who say you can adjust the MTU on the internet is a fool. First part of the session initiation that takes place will determine the largest mtu that can be used. It can be slightly different if you for example run a vpn that adds overhead to packets.
You can not increase the mtu over the common default value of 1500....and even then it most times uses stuff like 1460. You must in full control of every hop in the path to be able to increase the MTU. It is something that is done in data centers for disk networks it is not something you do over the internet. You also tend to need very specialized equipment because most consumer router and switches do not support larger MTU.

People really should stop listening to people on youtube. It would be very rare you find someone qualified. Almost everyone is some kind of entertainer or journalist first. Nobody with actual network/computer skills is going to waste their time on youtube when you make more money actually doing the job. It is almost always people that do not have the skills to get a real job in IT that you find on youtube.
 

Mariusglock

Commendable
Jun 13, 2020
162
27
1,640
9
""" Lots of text"""
Good advice, not to take guides from youtube seriously, since they make those only for revenue mostly.
I tried various fixes, and even thou i reverted to default values what i changed, even that did not solve the problem.
After some time, saving my projects, and files, I reinstalled windows since all other fixes did not help. Now it works as before.
View: https://imgur.com/a/zbYEN4s
 
At least windows is easier to reinstall than it used to be. It is unfortunate that you had to do it. Even though it takes more work in the future make the changes by hand and 1 at a time. Many places have the list of command you need to type in or the registry setting you need to change.

Torrent speeds are hard to predict since most times you are being limited by the upload speed of the other users. Speedtest and even steam use the same trick of sending the data over multiple parallel session except they all go to the same site. In theory in perfect condition torrents should get the same speed.

Pretty much if you get good numbers from speedtest your network setting are optimal. The only thing really different is speedtest is using HTTPS and torrent is using random ports.
 
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Mariusglock

Commendable
Jun 13, 2020
162
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At least windows is easier to reinstall than it used to be.
On my first machines 15 years ago, i used to spend days trying to reinstall OS (given i was still quite a noob back then, and CDs where quite unreliable :) with all the faulty CD drives, and scrached discs :) )

It is unfortunate that you had to do it.
No worries, these days systems take about 15 minutes to make a fresh install, compared to 15- 10 years ago, when it were hours with no end in sight.
I've saved all my projects on alternative drives, they're still intact :)

Even though it takes more work in the future make the changes by hand and 1 at a time. Many places have the list of command you need to type in or the registry setting you need to change.
I did make the changes 1 at the time ( be all i was doing only, was only pinging MTU values to see if they still caried without fragmenting packages, and then applying the biggest 'unfragmented' value), i even marked all the changes that i did (I did not use any 3rd party software) but upon reverting all the the changes it still did not work. So I had to revert to reinstalling the OS :)

Torrent speeds are hard to predict since most times you are being limited by the upload speed of the other users. Speedtest and even steam use the same trick of sending the data over multiple parallel session except they all go to the same site. In theory in perfect condition torrents should get the same speed.
)
That is out of my range of understanding, but could it be, that after changing the maximum packet size to send, i disturbed the data flow of pararel sessions (since they send the same ammount of data, but with different packet size?) * wild guess, since im not familiar with these concepts.

Pretty much if you get good numbers from speedtest your network setting are optimal. The only thing really different is speedtest is using HTTPS and torrent is using random ports.
Yeah, basically, my bandiwth is already optimall, only diference is that depending on the coutry where the 'server' is of your download, that what limits my bandwith speed.
 
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The reason for parallel streams is related to a concept called tcp window size. Years ago this was a huge issue when you had even moderate latency. The window is a number that represent the amount to data that can be instransit between 2 machines. This is actually many packets but at some point the sender will stop and wait until it gets confirmation that the data was received. When the latency is very large this can cap the transfer rate. So they send multiple streams each with its own window. Although the window size can be set fairly large now days there are considerations related to data loss and data retransmission that make it better to not use the absolute maximum window size. I am not sure windows lets you set this value and the sender can choose to ignore is and use a smaller window.
 
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