My Astaro sometimes fails to forward some ACK packets coming in via a tunnel.
The affected communication between a local client and a remote server (in fact a printer) starts comletely normal with the client transmitting data, the server replying and ACKing and all ACKs forwarded to the client so that he continues. (The problem occurs also in aother contexts, e.g. drive mapping across the tunnel does not work well; but the printer thing was easiest to reproduce)
At some point, however, I observe that the client gets stuck and retransmits some packet again and again.
To troubleshoot, I did a tcpdump in parallel on interfaces ipsec0 and eth0.
I see the retransmits enter on eth0 and leave towards the remote via ipsec0.
I also see corresponding ACKs enter via ipsec0 (which implies that the tunnel itself is ok, so it's none of those nasty MTU problems).
However, these ACKs are not forwarded to eth0![:O]
What can be the cause? [:S]
I even temporarily enabled a rule "Any / Any /Any" but without success.
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