ESP8266 TCP Source Port Uses Fixed Sequence

[brandond]

There is an issue with the esp8266 lwip library where the tcp_new() function uses a fixed sequence of source ports every time. This means that a node that is rebooting frequently and reconnecting to the same server may experience issues due to the host perceiving the packets as being retransmissions of old traffic - they have the exact same source, destination, and initial sequence number.

This has been reported and discussed in the Arduino core in esp8266/Arduino#632; their fix was to allow the user to call setLocalPortStart(), which sets an initial source port that is used (and incremented) to override local_port within the tcp_pcb returned by tcp_new().

Does ESPAsyncTCP have a work-around for this issue, and if not, could one be added? I believe I'm experiencing occasional dropped traffic caused by this oddity.

[mcspr]

@brandond just so you're aware, most recent Core version has a different approach for this. see esp8266/Arduino#5906

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[brandond]

So is this fixed, or just fixed in a different version of the lib?

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[mcspr]

Should be fixed upstream, Core >=2.5.2 with lwip2 selected will randomize ports by default

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[STALE_SET] This issue has been automatically marked as stale because it has not had recent activity. It will be closed in 14 days if no further activity occurs. Thank you for your contributions.

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[STALE_DEL] This stale issue has been automatically closed. Thank you for your contributions.