> The scope of what the daemon controls seems to be dependent on
 > implementation artifact rather than anything inherent about the
 > operation of the protocol, so that doesn't sound like the right answer
 > to me.

It is intended to be inherent -- the only thing that's supposed to be
configured is IP address (and its prefix length).  The route thing is a
mistake.  (I suppose there could be cases where one didn't want the IP
address, but that seems a bit strange -- DHCPINFORM seems a better fit
there.)

 > There's an argument (albeit a weak one, I think) to be made that the
 > IP address is "special" because it's associated with a lease, unlike
 > all the other parameters, and thus touching that value has "special"
 > consequences.  Maybe.

Yes, that's basically my argument.

 > > My concern is that after the renew fails, the client will obtain a new
 > > lease and clobber the statically configured address.  Given that the lease
 > > might be days or even weeks long, that's a long time between cause and
 > > effect -- and likely to be seriously inconvenient when it does occur.
 > 
 > A similar thing doesn't happen with ~IFF_UP change?  Wouldn't the
 > acquisition of a new lease possibly change the address in that case,
 > and probably also cause IFF_UP to be reinstated?

In order to acquire the new lease, at least one address on the interface
would have to be IFF_UP (which wouldn't happen in the if_mpadm(1M) case,
but could happen in the more general case).  Also, in the IFF_UP case, at
worst the machine will end up another IFF_UP IP address -- no existing
IFF_UP IP address will get clobbered.

 > Anyway, yes, I agree that'd be a bit annoying.  The documentation
 > should be clear:
 > 
 >      If you change a DHCP-configured parameter manually, your
 >      change will remain in effect as long as the DHCP server
 >      doesn't provide a different value for that parameter.
 >      However, if the server changes the parameter on a subsequent
 >      lease renewal -- which may well be days or weeks after you
 >      last modified the value.
 > 
 >      If you want your manually-configured values to remain in
 >      force, you should use an infinite lease time, change the
 >      server to provide the desired values, or terminate DHCP
 >      service for that interface.
 > 
 >      [This is where NWAM could insert an alternative based on
 >      setting the desired override parameter as part of some
 >      profile.]

Yes, we could document it -- or we could leave the current behavior.
Personally, I find the IFF_UP change easier to justify.

-- 
meem

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