(usagi-users 01173) Re: ISATAP feedback (was: version verification for ISATAP)

[Nathan Lutchansky <lutchann@xxxxxxxxxx>]

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On Thu, 17 Jan 2002, Craig Dunk wrote:

> I have ISATAP configured in a test deployment and have done nothing too
> strenuous with it yet, but here is some initial feedback based on first
> experiences. Please let me know if there is better list than USAGI for this.

I know of no better list, particularly since you're discussing the ISATAP
implementation that is integrated into the USAGI project.

> docs/ease of use:
> -Peter Bieringers work seems to be the authoritative reference for
> configuration of ipv6, I had a little trouble locating
> http://v6web.litech.org/isatap/. Merging the instructions with the (new) LDP
> site http://linuxdoc.org/HOWTO/Linux+IPv6-HOWTO/ would make it more
> accessible and increase awareness.

This is a good idea.  I wouldn't mind contributing the ISATAP HOWTO to
the Linux IPv6 HOWTO, and this seems like an appropriate place for it.

Peter?  How does this sound?

> -Extending the scripts (in Redhat) such that isatap can be controlled just
> by .conf files would be nice, but I realize this is very early and most
> people working with it so far won't care about this kind of thing.

I thought about distributing an init script to do this, but decided not
to, due to your next point.

> functionality:
> -If the ISATAP clients use dynamic addresses then the dependency on the
> local address when setting up the client is awkward for real deployments.

Yes, that is a bit of a problem.  I envision that ISATAP will be primarily
used in dynamic-IP environments, likely with DHCP clients on a corporate
network.

I think it is clear that the IPv4 address the client should use would be
the one assigned to the interface through which rtsol messages are routed.
There are two places this could be determined and set:

 a) the ISATAP kernel code
 b) init scripts that set up the is0 interface

Either way, the is0 interface can't be brought up until all IPv4
configuration is done.  Thus, since special care will be needed to
configure ISATAP anyway, I would say (b) is more appropriate.

The script for (b) would need something about as complex as:

    RADDR=192.168.1.1     (or whatever the ISATAP router is)
    LADDR=`ip route get $RADDR | head -1 | awk '{ print $(NF) }'`
    ip tunnel add is0 mode isatap local $LADDR v4any $RADDR ttl 64
    ip link set is0 up

Does anybody have any other suggestions?  -Nathan

- -- 
+-------------------+---------------------+------------------------+
| Nathan Lutchansky | lutchann@xxxxxxxxxx |  Lithium Technologies  |
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|  I dread success.  To have succeeded is to have finished one's   |
|  business on earth...  I like a state of continual becoming,     |
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