Hi,
I am facing a problem that I can’t diagnose on my own. I’ve been trying things during a month now, witout any success.
This issue was called into our attention by a customer oversas. They had a big trouble to send email to our server, which worked perfectly ok in this side of the ocean. My first thought was to blame the customer itself: ther connection, their mail program, the antivirus… it made sense as we didn’t find anything wrong on our side. After a teamviewer session I verified that the issue was real. I did a bit of wireshark on the connection and found that their connections got stalled and died from time to time. Sending smail emails worked most times, but big ones with attachments raised the problem everytime.
I found that there were too many “fast retransmission” and lost segments (as reported from wireshark->Analize ->expert
This retransmissions and lost segments were not a big problem with low latency networks, but were a complete blocker for overseas connections. I routed customer queries through an IP not behind the mikrotik router and solved the problem temporarily.
Some days after, suspecting that the router was unable to manage all the load, i replaced it. It was a 1100 AHx2 router, and was substitured by a ccr1036. The number of fast retransmissions decreased radically, but still happen from time to time.
I’ve run out of ideas here. Any expert that can share a clue?
