Gajim causes my router to block port 5222 ?
I use Gajim - amongst other clients - to connect to my own self-hosted Prosody server and I'm having a peculiar issue that only occurs when using Gajim (as far as I can tell). What happens is that sometimes, logging into my account will result in the 5222 port getting closed from the outside for precisely ten minutes, meaning it's still accessible from LAN. It thus prevents any other user on any other client to connect to my server, but yet does not affect the users already logged in what so ever. Since the port is opened on LAN, my best guess is that my router is blocking the port for a fixed amount of time when gajim tries to log in for some reason (although, like I said, it does not occur on every try, but it only happens with Gajim).
Here's gajim's logs obtained while asking Gajim to connect to my server. As you can see it failed and nmapping my server taught me the port 5222 got closed.
Server side, this connection attempt doesn't generate any output in my prosody log file (set to DEBUG level)
I actually did an experiment using Pidgin (Destkop), Xabber (Android), Yaxim (Android), Conversations (Android) and Gajim (Desktop), with multiple user accounts. I spammed the ON/OFF switch for the accounts on all these clients except Gajim for a while. The router didn't seem to sweat. I then switched Gajim ON : log-in attempt failed with the same output as in the log file I'm joining and the port got closed again.
I imagine I wouldn't be having this problem if I bridged my ISP router to a proper one (I deactivated IP flooding protections and every other protection related services for testing purposes but with no success) but my I'm wondering why this is only happening with this specific client.
And that's my question really. Does any of you have a clue about why or how this is happening ?