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Is there a way to use Wireshark to prove my ISP is throttling my internet?

asked 2018-11-01 01:31:03 +0000

BACKSTABUU gravatar image

updated 2018-11-01 01:35:11 +0000

Hey guys/gals,

As a hobby, I stream on I have been encountering issues recently (over the past month or so), where my up stream is solid at 3 mb/sec, and then hits a wall where the upload speed drops and jumps.

OBS shows the connection is faultering. I have trouble shot as much as I could on my own, as someone who is relatively tech-illiterate.

I have updated drivers, I have swapped out cables, modems, computers. All have shown the same issue. I am wondering if I can use wireshark to show that my ISP is dropping packets.

I apologize if this is not an appropriate question for this site, thank you for your help!

ETA: I know I am not hitting my max upload speed. I pay for 5 mb/s up. But I get this same issue even at 1.5 mb/s upload or below.

ETA2: I also have changed ingest servers when this happens to other servers that offer good connections, and the issue remains.

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answered 2018-11-01 15:22:52 +0000

updated 2018-11-01 15:28:59 +0000

The answer is the usual "it depends" :)

If you capture traffic on your PC while you have the issue you MAY see some errors or issues relating to TCP like retransmissions or window size of zero.

If your TCP traffic does not show "errors" or if your traffic is UDP then there is little you can check for to see if your ISP is throttling your connection.

Throttling happens on the ISP's network after the packets leave your PC.

You also need to keep in mind the issue may be on another part of the Internet and not just on your ISP's network. If your path TO or FROM Twitch has issues then your ISP can't possibly fix something outside their network. They can ask nicely if they have any sort of account with the affected party.

Big enough ISP probably peer with Twitch so they have a direct connection to them. If that link is not "big enough" during peak hours than it may fell like you are being throttled although you should experience packet loss that translate in lag or lost frames in your video.

Hope this helps.



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It does help, thank you. I have Wireshark recordings of when this occurs, and there are a ton of TCP Dup ACKs, TCP Fast Retransmissions, TCP Retransmissions, and some TCP Out-of-Orders, etc.

I don't see Window Size of Zero.

Should I post the log?

Twitch has a third-party program called Twitch Test that tests your connection to their servers over a given amount of time, like 30 seconds or more, and the servers that I connect to are all > 3 mb/s. I don't know if that shows that the connection to Twitch is stable or not.

So maybe its intentional Packet-Reordering by my ISP? I don't know. Its difficult to find a way to prove that this is done intentionally on their end or if there's some genuine problem.

BACKSTABUU gravatar imageBACKSTABUU ( 2018-11-01 16:13:49 +0000 )edit


TCP Retransmission and duplicate ACKs are signs of packet drops. If you are dropping packets then this is impacting your performance on the network for sure.

Statistics -> TCP Stream Graphs can help you visualize your trace.

You do need to make sure the retransmission and duplicate ACKs are for addresses used for Twitch.

You may use Geo IP in Wireshark to see who owns the IP. (

Geo IP will add data in the IP layer for the Autonomous System and its owner if available. Twitch uses at least AS 46489.

You may manually check the ARIN WHOIS ( to check who own the IP.

I like to use WinMTR ( to check for packet loss along a path. You may be able to "see" where you are dropping packets. The only thing is that any traceroute utility shows ...(more)

Spooky gravatar imageSpooky ( 2018-11-06 01:49:56 +0000 )edit

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Asked: 2018-11-01 01:31:03 +0000

Seen: 4,031 times

Last updated: Nov 01 '18