CODEWITHSUNDEEP
tcp
JVMX
JVMX

Reputation: 1078

Bad Checksum on TCP packets/ UDP traffic is just fine

I know only enough about packet traffic to make a lot of very bad assumptions. I am turning to the collective wisdom of Stackoverflow to help me out a little bit.

Unsurprisingly, I feel that my Internet provider (lets just call them 'big cable') is blowing a bunch of smoke up my butt when it comes to solving a technical issue.

I can only open simple web pages. Pages loaded down with a lot of includes, large javascript libraries, big Styles Sheets, google analytics etc simply stall out. I can see that the index.html file loads just fine using curl.

My cable prover hooks up speedtest.net and say "See it goes just as fast as it should".

When I open a packet sniffer however I can see that between 50% and 95% of the incoming TCP packets at any given time have a bad Checksum. ANd when i get too high a percentage of bad checksum, my browser will timeout loading the page. Streaming video and Voip are just fine however.

I am making a few assumptions here that I would like to have verified.

  1. Voip, streaming video and speedtest are usually UDP packets not TCP?
  2. The reason the video loads but the web page does not is that the Checksum is not applied to UDP packets.

I have come up with an analogy that I would like someone to confirm its accuracy: It is as if FedEx was delivering my packages on time, but smashed beyond usefulness.

Finally. As they are using the speediest.com result to keep me stuck to my contract. What can I do to either help them fix the mess or prove to them they in fact have a mess?

Upvotes: 0

Views: 2025

Answers (1)

user2366842
user2366842

Reputation: 1216

This belongs on ServerFault, not StackOverflow.

  1. not sure about speedtest, but Voip and video streaming are generally UDP.
  2. If your suspicion is correct, then yes, this is also correct.

If i were you, i'd call them up, and go up their ladder (ask to speak to the manager, ask to speak to their manager, etc all the way up the line) and talk to someone with real power that might be able to actually help you with the situation. If they are in fact interfering with your TCP traffic, they are likely in breach of contract, as they aren't delivering the service they have advertised.

Upvotes: 1

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