Re: linux 5.17.1 disregarding ACK values resulting in stalled TCP connections

[Eric Dumazet]

On Sat, Apr 2, 2022 at 9:29 AM Neal Cardwell <ncardwell@xxxxxxxxxx> wrote:
>
> FWIW those log entries indicate netfilter on the mail client machine
> dropping consecutive outbound skbs with 2*MSS of payload. So that
> explains the large consecutive losses of client data packets to the
> e-mail server. That seems to confirm my earlier hunch that those drops
> of consecutive client data packets "do not look like normal congestive
> packet loss".


This also explains why we have all these tiny 2-MSS packets in the pcap.

Under normal conditions, autocorking should kick in, allowing TCP to
build bigger TSO packets.