On Thu, Sep 11, 2014 at 03:25:57PM +0200, Sean Durkin wrote:
> I can contact support, but they of course charge you for
> everything they do, and as long as I haven't ruled out that the
> reason is just some stupid configuration mistake on my part (or a
> routing/filtering issue at my hosting provider, or Amazon, or...),
> I don't want to start replacing hardware, obviously...
The Postfix configuration has no impact on the TCP layer, beyond
optionally specifying the TCP window size. Since it is the TCP
layer that fails, the problem is not related to the Postfix
configuration.
Your PCAP files should demonstrate repeated retransmission of data,
are the ACKs you're sending confirming receipt of packets that are
sent repeatedly? In that case your ACKs are getting lost? Is
there a sequence number gap in the data received from the server?
In that case the remote server's data is getting lost. Does the
capture confirm that window scaling is not in use? ...
--
Viktor.
