I have an ADSL router (model Pirelli DR A226G) that seems to cause dropped tcp/ip connections (not ADSL connection per se). I have tracked it using Wireshark and captured a few cases and they always are like this:
first a few out of order tcp retransmissions happen (or at least they're interpreted as such by wireshark)
then a RST packet is issued by the adsl modem to a local address. Often wireshark says "this is an ack to segment in frame" and it leads to the last packet outgoing from local machine to the remote machine (behind ADSL modem) and that packet is seemingly innocent PSH, ACK packet.
The result is ssh client saying "write failed: broken pipe". This happens really frequently (interval is random, from dozens of seconds to dozens of minutes). Similarly RDP connections are being broken as well.
I managed to capture "reset cause" in wireshark a few times, but cannot decode it at all, it looks like:
Reset cause: \3224\230\205\214...
Questions:
what's the reason for those frequent RSTs?
is there a way to decode the "reset cause" msg content? It's OpenSSH server and client and Linux on both ends, so in theory it should be possible? Or is the ADSL modem that is resetting this and it's not possible?