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    Dropped packets - how many is normal?
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    Dropped packets - how many is normal?

    So I recently started playing with netdata. Turns out one of my KVM servers is dropping a lot of incoming packets - consistently around 50-60 each second.

    The server is basically idle. I can see the dropped count increasing with watch ifconfig ens3 looking under RX/dropped.

    I did try exploring with tcpdump: it shows lots of ARP and "ICMP6 neighbor solicitation" packets. The server has IPv6 disabled at the kernel, so I guess I should expect a few dropped packets from that, but 60/second seemed surprising!

    Comments

    • deankdeank Member
      edited October 19

      Let your host know.
      Then cancel your plans with them OR chargeback.
      Then sue for mental damage.

      Thanked by 1notty

      If you can't make your point within 5 lines of words, you have an optimization issue.
      Amitz day is October 17th.

    • JordJord Moderator, Provider

      Das nicht gut

      BaseServ Ltd - UK Shared DirectAdmin Hosting | Litespeed + Cloudlinux + Free Backups. BaseServ Certified to ISO/IEC 27001: 2013

    • None, null, nill, zero. Packets must be delivered no matter what.

      Wordpress Hosting - Home made!

    • ClouviderClouvider Member, Provider

      If you can see them in your OS that means they are dropped by your kernel.

      Thanked by 2Janevski notty

      Clouvider Leading UK Cloud Hosting solution provider || UK Dedicated Servers Sale || Tasty KVM Slices || Latest LET Offer

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    • jarjar Provider
      edited October 19

      I hate this meme but it’s too perfect for the thread: https://cloud.donnell.online/index.php/s/YDJokepoiWJ8cmM

      (Yes I only based this on the thread title)

      Thanked by 1notty
    • rm_rm_ Member

      notty said: The server is basically idle. I can see the dropped count increasing with watch ifconfig ens3 looking under RX/dropped.

      This means nothing. Packets can be dropped for various reasons, including due to being not addressed to your host (or to any multicast group it's a member of, or as you noticed, if you have IPv6 disabled). Run a long ping or mtr to measure if you have any actual packet loss.

    • Do a tcp speed test.

      You won't be able to achieve the advertised high speeds if there's even a slight loss.

      You are dreaming. | And it's a nightmare. | THE SECRET THREAD | THE TRUTH | HAVES YOU SEEN THIS YURA?

    • nottynotty Member

      Thanks for the advice and Dr Who memes.

      So I ran a couple of long tests with ping 8.8.8.8 and actually there was a small amount of packet loss (around 1%) but I'm not sure if that's relevant.

      It looks like the 60 packets being dropped per second are all "ICMP6 neighbor solicitation". The tcpdump logs are full of this sort of thing:

      16:09:46.038688 IP6 fe80::xxxx:xxxx:xxxx:xxxx > xxxx:xxxx:xxxx:xxxx:xxxx: ICMP6, neighbor solicitation, who has xxxx:xxxx:xxxx:xxxx:dead:babe:f00d:cafe, length 32

      Yes, note the "fun" IPv6 address... not sure what to make of that too... perhaps someone is sending me encoded messages!

    • @notty said:
      Yes, note the "fun" IPv6 address... not sure what to make of that too... perhaps someone is sending me encoded messages!

      That's Hexspeak.

      Thanked by 1Janevski
    • notty said: not sure what to make of that too... perhaps someone is sending me encoded messages!

      Have you noticed how they put cabbages inside salads?
      Well, that's pretty much the same thing.

      You are dreaming. | And it's a nightmare. | THE SECRET THREAD | THE TRUTH | HAVES YOU SEEN THIS YURA?

    • nottynotty Member

      LOL what is this forum I have joined??

      So just to ensure I have understood correctly,

      • IPv4 = Lettuce
      • IPv6 = Cabbage
      • I went to the "dead babe f00d" cafe and ordered some salad
      • But instead of lettuce I ended up getting cabbage
      • In fact someone started firing 60 cabbages at me every second
      • But it's ok, because they are multicast cabbages and can be ignored
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