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From: Lowell Gilbert <freebsd-questions-local@be-well.ilk.org>
To: Ihsan Junaidi Ibrahim <ihsan.junaidi@gmail.com>
References: <D50DA316-4951-4B46-94CD-809E66EBB20D@gmail.com>
Date: Wed, 19 Oct 2011 09:11:19 -0400
In-Reply-To: <D50DA316-4951-4B46-94CD-809E66EBB20D@gmail.com> (Ihsan Junaidi
	Ibrahim's message of "Tue, 18 Oct 2011 20:44:50 +0800")
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Cc: freebsd-questions@freebsd.org
Subject: Re: Maximum gif(4) interfaces
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Ihsan Junaidi Ibrahim <ihsan.junaidi@gmail.com> writes:

> I need to build a system that need to terminate a number of 6-in-4 and 4-in-4 tunnels.
>
> Can someone point me to a direction, with gif auto-cloning and on GENERIC, what is the maximum number of gif interfaces/tunnels that can be supported?
>
> I'm on 8.2.

The implementation is in src/sys/net/if_gif.c.

There is no absolute limit to the number of cloned interfaces.  They are
stored in a linked list (as are interfaces as a whole), so having large
numbers of them could be a performance issue in some cases.  I would
guess that such cases would mostly involve having high rates of tunnel
creation and destruction, but you would have to test to be sure.