TCP Dropped Packets
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Hello All,
just wondering if its possible (and how) to monitor dropped packets on an interface. I've got an unreliable link connected to an interface on my PFSense box and I want to simply capture (somehow) the percentage of dropped packets, specifically thinking of the TCP retransmits for CRC errors and things of that nature. The link uses a Powerline AV system which is not very reliable, so I want to know what percentage of packets are dying in that link.
Thank you,
Lucas -
The simplest way is to use ping of some sort. I know the WAN side supports the quality graph. Actually seeing CRC errors should almost never happen. Most switches and bridges/transceivers use store-and-forward and will drop the frame before you ever see it.
Similar with TCP re-transmission, but not quite identical. You don't actually see a dropped packet, you infer it by receiving a sequence number to that is beyond what you've received. pfSense is technically stateful, so it should be able to tell when this event occurs, but I wouldn't think it normal to log that event in anyway, it typically just quickly gets fixed via an SACK. I assume pf leaves that up to the client.
I would still be interested to know if there are tools to simply do this.
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Powerline doesn't like certain things with it on the circuit.
Are you able to troubleshoot isolating it?
You don't happen to have a microwave or laser printer on the same circuit do you?