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Date:      Tue, 15 May 2012 15:41:25 +0200
From:      Chris Knipe <>
To:        Brett Glass <>
Subject:   Re: Maximum number of "tun" pseudo-devices
Message-ID:  <>
In-Reply-To: <>
References:  <>

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On Mon, May 14, 2012 at 3:09 AM, Brett Glass <> wrote:
> I'm running a busy FreeBSD-based that may handle large numbers of
> simultaneous connections. I'm currently using software that creates a "tun"
> device for each connection. However, after it hits tun127 (128
> pseudo-devices), it doesn't seem to want to create any more. What sets the
> limit on the number of "tun" devices that can exist in the system, and how
> can the limit be adjusted? Is there a similar limit on, say, "ng" devices?

You don't say which version of FreeBSD you're using, but older
versions of FreeBSD had the option to specify a maximum number of
pseudo-device to allow.  For example

pseudo-device   tun        1   # Tunnel driver(user process ppp)

In your kernel would only allow for 1 tun device to be created.

If you're using an older (5.x / 4.x) version of FreeBSD, I'd say check
your kernel config.  Nut sure whether this is still relevant in newer
versions of FreeBSD, but documentation suggest that it is no longer
the case with newer versions.


Chris Knipe

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