(usagi-users 01182) Re: ISATAP feedback

[Craig Dunk <CDunk@xxxxxxx>]

How does the implementation in scripts work in cases where the ipv4 address
changes either from (for example) reconnection of the link in another subnet
or dhcp lease expiry/reassignment? (I guess normally the same address will
be assigned in the dhcp case)

This also reminds me: 

In section 5.1 of the draft should their be a mechanism for re-determining
the router prefix? I appreciate the low overhead of the isatap mechanism
(doesn't require broadcast and doesn't require a static set up and doesn't
require state on the router side) and I realize this shouldn't become
"mobileip", but I am looking at this in the context of a mobile environment
so I see a need to rediscover a current local address. 

Thoughts?

Craig.


>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.
We have also mechanism to run setup things after network starts, see
"init.ipv6-global" parameter "start post". Perhaps a better hook. Or
using something similar like current 6to4 setup.


>     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
Sounds similar to 6to4 setup in "ifup-ipv6", have a look there. I can
add some isatap functions also in "network-functions-ipv6" - or you
contribute them.