Webswitch 1216H Support in English > Configuration, Webswitch 1216H

RC-1216H Webpage connection

<< < (3/5) > >>

Jan (Microbit):
Then what does not make sense is why the PC and its web browser cause the source port number to increase for every request made?

Jan (Microbit):
But the TCP/IP stack we are talking about is the one in the PC, meaning it isn't possible to inspect it on a source code level. The only thing which is under our control is how the Javascript, which runs in the PC's web browser, behave and that script merely sends periodically HTTP requests to the 1216.

This behaviour of incrementing port numbers is called "ephemeral port".
When the connection terminates, the ephemeral port is available for reuse, although most IP stacks won't reuse that port number until the entire pool of ephemeral ports have been used.  So, if the client program reconnects, it will be assigned a different ephemeral port number for its side of the new connection.
Look for the words "ephemeral port" on the internet and you will find the explanation.


Jan (Microbit):
Then I see interesting problems arising in many, if not all, AJAX web page scenarios where the browser issues periodically requests in order to achieve updates of only parts of the web page if the router/firewall consider that being DoS behavior.

This is a very interesting discussion. I had some issues with my webswitch operating as antenna rotator-interface with an old hygain-rotator. Sometimes you could start the rotator, the brake is open, but the rotator appeared to be blocked. Listening to the signals, I had the impression that the antenna is turning despite the static view of the display. Other users had the same issues. Switching off the SPI in the router solved this problem, now the display is working fine again!
Had this issue on a dlink-router.

73 de Mark, HB9AZT


[0] Message Index

[#] Next page

[*] Previous page

Go to full version