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I am trying to go from my web address to a virtual machine.

I have Ubuntu 16.04 as a guest in Virtual Box.

I have set up port forwarding on my router so that traffic on ports 1935 and 5080 get directed to this virtual machine.

I have also tried setting up port forwarding from the router to the host and configuring port forwarding in Virtual Box so that my guest virtual machine sees the traffic on 1935 and 5080.

I receive the Frame Check Sequence Incorrect error in my capture on the host computer.

But what does it mean and what causes it ?

Wireshark from Windows Host

asked 27 Sep '16, 06:54

kam2700's gravatar image

accept rate: 100%

edited 27 Sep '16, 06:56

It turns out the problem was when port forwarding from the router I had to enable TCP/UDP then it worked.

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answered 29 Sep '16, 03:15

kam2700's gravatar image

accept rate: 100%

I think this is a capture problem - I've seen packets like this when capturing VMs on the host, and they're not really being sent to the network. No idea what causes those.

What I would recommend is to capture the traffic with a device that isn't involved in the communication (dedicated capture laptop/PC) via TAP or SPAN port. Otherwise your readings are incorrect.

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answered 27 Sep '16, 07:07

Jasper's gravatar image

Jasper ♦♦
accept rate: 18%

Big chance the capture engine gets confused by real vs virtualised network interface capabilities, and likely assumes the FCS is there while it's not. Try modifying the Ethernet dissector preferences (disable: Assume packets has FCS and Validate the Ethernet checksum if possible).

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answered 27 Sep '16, 07:17

Jaap's gravatar image

Jaap ♦
accept rate: 14%

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question asked: 27 Sep '16, 06:54

question was seen: 1,483 times

last updated: 29 Sep '16, 03:15

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