[Icecast-dev] multiple connection (be careful with carrier-grade NAT)

Marcin Lewandowski marcin at saepia.net
Tue Jul 5 13:31:24 UTC 2016

As I have written before, I’ve seen that if broken html5 <audio> players
were used but then amount of connections was gradually increasing.


On 5 lipca 2016 at 12:39:54, Yaniv Sharon (yaniv.sharon at gmail.com) wrote:


Yes I aware to the NAT possibility,
But let's assume that this is the issue, there is no reason that 30
>From the same country will connect and disconnect at the same time range...

I'm pretty sure that its individual listener/IP.
I deleted the Access log files, but in the next time that I will catch
similar situation again,
I will complete the investigation.

Nobody from you folks get into situation like mine before?

-----Original Message-----
From: Icecast-dev [mailto:icecast-dev-bounces at xiph.org] On Behalf Of
Christoph Zimmermann
Sent: Saturday, July 02, 2016 12:32 AM
To: icecast-dev at xiph.org
Subject: Re: [Icecast-dev] multiple connection (be careful with
carrier-grade NAT)

Hi all

> I didn't pick up the data from the access file, just from the error
> file...

I would have a look at them. My guess is (I explain below why) that you
will see different agents for your multiple connections.

> The situation that I'm describing is very different, 20-30 (and once
> even almost 40) "listeners" from the same IP, for a long time. Each
> "listener" using true bandwidth.
> The IP source is from Vietnam, Korea...i really think that abusing its
> what I'm talking about.
> ( What a mobile device will handle 30 instances for 20 minutes? )

The short answer is: Carrier-grade NAT

Longer story:
Back in 2011 the available IPv4 addresses ran out. All of them.
As you know, you need a public IP address to be able to receive Data from a
server. But in the meantime several hundred million mobile phones got
connected to the Internet.

An ugly way to handle this bad situation is to use Carrier-grade NAT, means
that thousands of mobile phones share the same public IP address.
The clean solution would be to use IPv6. Icecast is IPv6 ready.

I'm quite sure that it explains your situation, especially because you get
this connections from Korea and Vietnam. The Asian region has much fewer
IPv4 addresses to use compared to earlier connected regions (USA, EU), so
Carrier-grade NAT is way more common in Asian mobile networks.

I was searching for a good explanation and a list or so of networks known
to use Carrier-grade NAT. But I didn't found a list. This presentation is
somewhat OK for what I explained:

> Any idea to handle situation like that one?

Be happy and celebrate that you have so many listeners from this countries.

All the best,
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