[Icecast] "Ghost" connections causing connection limit to be reached

[Rob Hailman]

Hello,

I've been having an issue periodically where our Icecast server (which is
set to a max 200 connections) will reach that limit and start rejecting all
connections, but most of the connections don't seem to be real active
listeners.

We are running icecast 2.4.4, installed via apt on Ubuntu 22.04.1 LTS.

We have four streams - two mp3 and two ogg. It seems like what is happening
is that connections to the ogg streams are never getting released - so the
number of clients will go up and up until all 200 connections are taken up.
An excerpt from error.log, showing the mp3 stream count fluctuating but the
.ogg count only increasing:

[2023-01-29  10:25:46] INFO source/source_main listener count on /hi-fi now
6
[2023-01-29  10:25:47] INFO source/source_main listener count on /hi-fi now
5
[2023-01-29  10:25:47] INFO source/source_main listener count on /hi-fi.ogg
now 124
[2023-01-29  10:25:51] INFO source/source_main listener count on /hi-fi now
4
[2023-01-29  10:26:17] INFO source/source_main listener count on /hi-fi.ogg
now 125
[2023-01-29  10:26:47] INFO source/source_main listener count on /hi-fi.ogg
now 126

When I restart icecast, the logs will show all 200 connections being
released - and in access.log, most of the .ogg connections will be for very
long durations with very small amounts of data transferred - for example:

77.88.9.3 - - [02/Feb/2023:21:40:29 +0000] "GET /hi-fi.ogg HTTP/1.1" 200
422 "-" "Mozilla/5.0 (compatible; YandexBot/3.0; +http://yandex.com/bots)"
2694965

If I'm reading that correctly, the connection was open for 31 days with 422
bytes transferred.

Many (but not all) of these connections seem to be bots.

Would be happy to provide the full log files but didn't want to send >1MB
files to the whole list.

Is this a possible configuration issue, an Icecast bug, or something else?
Any help or suggestions would be greatly appreciated!

Thanks,
Rob
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