Hint: many "Requested crypt-nonce resync" log entries

[draxinusom]

Not a problem per se but just a little hint for other server operators who might see this issue. When I first encountered the problem, I did not find many hints with google searching for the log-line, so this here is just a FYI. May it be useful:

You have some users who have problem on Mumble, such as they lose the capability to speak or sometimes to hear (or both) after a random duration on being logged in and you see a lot of "Requested crypt-nonce resync" messages in the log (usually around 5 to 10 per minute).

The problem seems to be caused by the user's router/internet access device. Certain firmwares/devices of at least one "FritzBox" seem to have the problem. It appears that the problem is, that the router in question has a problem with both a TCP and a UDP data stream coming from the same IP/Port combination and is somehow either mixing them up or randomly dropping packets from one (or both). The result is that the security layer breaks and causes the log messages to appear, combined with the user unable to speak/hear. It might resolve itself over time or not.

Solution is to have these users switch to "TCP only" mode, which seems to work for the time being. They might still occasionally produce said log messages, but they don't feel service interruption.

Note that not all devices seem to exhibit this problem. Some users have the same box (and firmware) and don't have the problem at all.

[kruegerfreddy]

I once had a problem with a user who's IP-Router had trouble reconect to my mumble server. It turned out that he had checked in the router internal firewall settings a option that was called "Flood-Protection". It seamed that this option looked for mutiple IP streams coming into his local network coming from the same IP adress (my mumble server).

After he had truned that option of he was able to play flawless. So what Im suggesting is, that it might be worth to look into the router's internal firewall settings sometimes.

[kissaki]

Did you ask those users to update their FritzBox firmware?

That could very probably fix the issue for them.

If not, did you report it to AVM, the FritzBox manufacturer?