That is interesting.  However, I have never seen a server configuration that
didn't have a lease time specified in it - so in practice, it is probably
meaningless to request a given lease time.

Tom Veldhouse
veldy at veldy.net

----- Original Message -----
From: "Adam Maloney" <adamm at sihope.com>
To: <tclug-list at mn-linux.org>
Sent: Tuesday, October 03, 2000 10:45 AM
Subject: Re: [TCLUG:21970] Should DSL or Cable modem


> man dhcpcd...
>
>        -l leasetime
>               Specifies (in seconds) the recommended  lease  time
>               to  the  server. (Note that the server can override
>               this value if it sees fit). This value is  used  in
>               the  DHCP_DISCOVER message. The default is infinite
>               (0xffffffff).
>
> By default the client will request infinity, and the server will send it's
> configured default lease time back in the Offer.  You can't force it from
> the client side, the server always wins (just like Awk!)
>
> Adam Maloney
> Systems Administrator
> Sihope Communications
>
> On Tue, 3 Oct 2000, Thomas T. Veldhouse wrote:
>
> > He seemed to be talking about changing the lease time in the already
> > negotiated lease file.  I wasn't aware you could even configure DHCP
clients
> > to ask for a given release interval.  I never saw such an option when
> > setting up DHCP client.
> >
> > Tom Veldhouse
> > veldy at veldy.net
> >
> > ----- Original Message -----
> > From: "Adam Maloney" <adamm at sihope.com>
> > To: <tclug-list at mn-linux.org>
> > Sent: Tuesday, October 03, 2000 10:23 AM
> > Subject: Re: [TCLUG:21970] Should DSL or Cable modem
> >
> >
> > > No, if he tells the client to ask for a lease time of 3 weeks, the
client
> > > sends that during the negotiation. The server can reject that lease
time
> > > if it's too long with a NACK followed by another OFFER with a more
> > > plausible lease time.
> > >
> > > Maybe I mis-understood what he said though.  Did he just change the
lease
> > > time in the file that dhcpcd writes with the state information?
That's
> > > bad.  Really bad.  If he changes the lease time there then the server
> > > doesn't know about it.  Then you're right, if he sets that to 3 weeks
and
> > > the initial lease was for 2 weeks, then after 2 weeks the server will
be
> > > expecting a renew that it will never get.  It'll assume the client's
gone
> > > and put the IP back into the pool.  If a new subscriber came along
they
> > > could snag up "his" IP legitimately.  Then after a week his client
will
> > > try to renew the IP and the server will NACK it because it's already
been
> > > leased.  Not to mention all the problems he'd have with IP conflicts.
> > >
> > > Adam Maloney
> > > Systems Administrator
> > > Sihope Communications
> > >
> > > On Tue, 3 Oct 2000, Thomas T. Veldhouse wrote:
> > >
> > > > Right.  But if he changes the lease time to 3 weeks, but the server
is
> > > > configured for 2 weeks, there may be a 1 week period where two
different
> > > > computers share the same IP address, because somebody else has
received
> > the
> > > > IP address, and his computer will not ask to renew the old IP
address
> > for
> > > > another week yet.
> > > >
> > > > Tom Veldhouse
> > > > veldy at veldy.net
> > > >
> > > > ----- Original Message -----
> > > > From: "Adam Maloney" <adamm at sihope.com>
> > > > To: <tclug-list at mn-linux.org>
> > > > Sent: Tuesday, October 03, 2000 9:30 AM
> > > > Subject: Re: [TCLUG:21970] Should DSL or Cable modem
> > > >
> > > >
> > > > > Well if his dhcp client sends a Renew request to the server, the
> > server
> > > > > can reject it.  The dhcp client will then just ask for a new IP.
As
> > long
> > > > > as he doesn't muck with the client (or bypass it altogether and
just
> > > > > statically configure it) he can't cause any trouble.  The server
can
> > > > > always reject renew requests if the address has already bgeen
> > reassigned.
> > > > > I don't think there's anything he can do to the configuration of
the
> > > > > client that could screw anything up, I think he'd have to modify
the
> > > > > source.
> > > > >
> > > > > If the IP has already been leased to someone else, and his client
asks
> > for
> > > > > that IP (in a renew request) the server will send a NACK back,
then an
> > > > > OFFER with a new IP.
> > > > >
> > > > > In any case, by changing the lease time you're probably not
helping
> > > > > yourself at all.  As soon as the lease ends your client will send
a
> > renew
> > > > > request back to the server and you'll get your IP back anyways.
The
> > lease
> > > > > time just dictates how long before you have to renew again, but if
the
> > > > > server reboots you may be SOL.  I believe ISC's stores the lease
> > > > > information in /var somewhere so if the server restarts it'll know
who
> > has
> > > > > what leased...but I don't know about whatever DHCP server they're
> > using.
> > > > > If it's Microsoft's it'll probably explode or something...
> > > > >
> > > > > Adam Maloney
> > > > > Systems Administrator
> > > > > Sihope Communications
> > > > >
> > > > > On Tue, 3 Oct 2000, Thomas T. Veldhouse wrote:
> > > > >
> > > > > > Yeah, and that somebody is going to be pissed if they find out
that
> > > > somebdoy
> > > > > > is using their IP and causing them to have problems with there
cable
> > > > modem.
> > > > > > Most users are not going to know what the problem is and they
are
> > simply
> > > > > > going to call MediaOne and complain.  If MediaOne then finds
this,
> > one
> > > > had
> > > > > > better watch out, because suddenly the support costs are larger
than
> > the
> > > > > > profits that they are making off of the trouble causing
individual.
> > > > > >
> > > > > > Tom Veldhouse
> > > > > > veldy at veldy.net
> > > > > >
> > > > > > ----- Original Message -----
> > > > > > From: "Adam Maloney" <adamm at sihope.com>
> > > > > > To: <tclug-list at mn-linux.org>
> > > > > > Sent: Tuesday, October 03, 2000 9:17 AM
> > > > > > Subject: Re: [TCLUG:21970] Should DSL or Cable modem
> > > > > >
> > > > > >
> > > > > > > Well if they ran ISC's DHCPd they can set Max-Lease-Time,
which is
> > the
> > > > > > > maximum amount of time a given address will be leased for.
That's
> > not
> > > > to
> > > > > > > say that when the lease expires you won't renew and get it
again,
> > but
> > > > if
> > > > > > > you don't renew right away someone else will probably get it.
> > > > > > >
> > > > > > > Adam Maloney
> > > > > > > Systems Administrator
> > > > > > > Sihope Communications
> > > > > > >
> > > > > > > On Mon, 2 Oct 2000, Eric F Crist wrote:
> > > > > > >
> > > > > > > > Trust me, it works.  I've gotten calls from TW and MediaDumb
> > (aka
> > > > ATT)
> > > > > > and
> > > > > > > > they've not been able to stop it, short of pulling the
provision
> > for
> > > > > > your MAC
> > > > > > > > address.
> > > > > > > >
> > > > > > > > But, there are ways around that too.  =P
> > > > > > > >
> > > > > > > > On Mon, 02 Oct 2000, you wrote:
> > > > > > > > >
> > > > > > > > > Thats *only* if the other end accepts such bad things.
> > > > > > > > >
> > > > > > > > > AFAIK, you can setup ISC to ignore it.
> > > > > > > > >
> > > > > > > > > * Eric F Crist <ecrist at ardent-hacker.net> [001002 21:37]:
> > > > > > > > > > After a little more research (I had a brain-fart) the
file,
> > on a
> > > > > > freebsd =
> > > > > > > > > system
> > > > > > > > > > is /var/db/dhclient.leases
> > > > > > > > > >=20
> > > > > > > > > > This file is realatively simple and straightfoward.  For
> > > > information
> > > > > > on y=
> > > > > > > > > our
> > > > > > > > > > box, type man dhclient.leases
> > > > > > > > > >=20
> > > > > > > > > > If you have questions or comments, feel free to email
me.
> > > > > > > > > >=20
> > > > > > > > > >=20
> > > > > > > > > >=20
> > > > > > > > > > Au Contrair on the static IP.  If you're into the
computer
> > > > hacking
> > > > > > side of
> > > > > > > > > > things, you can simply change your lease on the IP to
never
> > > > expire.
> > > > > > Ther=
> > > > > > > > > e's a
> > > > > > > > > > file located on your hard drive that actually sets your
> > lease.
> > > > This
> > > > > > is
> > > > > > > > > > overwritten at the time of renewal by the DHCP server.
I
> > have
> > > > done
> > > > > > this =
> > > > > > > > > myself
> > > > > > > > > > and know others who do it successfully.  Maybe not a
legit
> > > > static
> > > > > > IP, but=
> > > > > > > > >  until
> > > > > > > > > > they find out, who cares?=20
> > > > > > > > > >=20
> > > > > > > > > > On Mon, 02 Oct 2000, you wrote:
> > > > > > > > > > > Disadvantages to cable modem (from my point of view)
> > > > > > > > > > > - no static IPs, may be coming soon though
> > > > > > > > > > > - no services on your machine, or you get booted
> > > > > > > > > > >=20
> > > > > > > > > > > Advantages to cable modem
> > > > > > > > > > > - much faster
> > > > > > > > > > >=20
> > > > > > > > > > > I got this information from the Time Warner sales rep
and
> > the
> > > > tech
> > > > > > rep =
> > > > > > > > > that
> > > > > > > > > > > showed up at my apartment complex trying to get
> > subscribers.
> > > > > > > > > > >=20
> > > > > > > > > > > --=20
> > > > > > > > > > > Jon Schewe | http://eggplant.mtu.net/~jpschewe
> > > > > > > > > > > For I am convinced that neither death nor life,
neither
> > > > angels=20
> > > > > > > > > > > nor demons, neither the present nor the future, nor
any=20
> > > > > > > > > > > powers, neither height nor depth, nor anything else in
> > all=20
> > > > > > > > > > > creation, will be able to separate us from the love of
God
> > > > that=20
> > > > > > > > > > > is in Christ Jesus our Lord. - Romans 8:38-39
> > > > > > > > > > >=20
> > > > > > > > > > >=20
> > > > > > > > > >
> > > > > >
> > > ---------------------------------------------------------------------
> > > > > > > > > > > To unsubscribe, e-mail:
> > tclug-list-unsubscribe at mn-linux.org
> > > > > > > > > > > For additional commands, e-mail:
> > tclug-list-help at mn-linux.org
> > > > > > > > > > --=20
> > > > > > > > > > Eric F Crist
> > > > > > > > > > System Administrator
> > > > > > > > > > Ardent-Hacker.net
> > > > > > > > > >=20
> > > > > > > > >
> > > > > >
> > > ---------------------------------------------------------------------
> > > > > > > > > > To unsubscribe, e-mail:
tclug-list-unsubscribe at mn-linux.org
> > > > > > > > > > For additional commands, e-mail:
> > tclug-list-help at mn-linux.org
> > > > > > > > > >=20
> > > > > > > > >
> > > > > > > > > --=20
> > > > > > > > > Scott Dier <dieman at ringworld.org> #nicnac at efnet=20
> > > > > > > > > http://www.ringworld.org/
finger:dieman at destiny.ringworld.org
> > > > > > > > >
> > > > > > > >
> > > > > > > > ----------------------------------------
> > > > > > > > Content-Type: application/pgp-signature; name="unnamed"
> > > > > > > > Content-Transfer-Encoding: 7bit
> > > > > > > > Content-Description:
> > > > > > > > ----------------------------------------
> > > > > > > >
> > > > > > > > ----------------------------------------
> > > > > > > > Content-Type: text/plain; name="unnamed"
> > > > > > > > Content-Transfer-Encoding: 7bit
> > > > > > > > Content-Description:
> > > > > > > > ----------------------------------------
> > > > > > > >
> > > > > > > > --
> > > > > > > > Eric F Crist
> > > > > > > > System Administrator
> > > > > > > > Ardent-Hacker.net
> > > > > > > >
> > > > > > >
> > > >
> ---------------------------------------------------------------------
> > > > > > > > To unsubscribe, e-mail: tclug-list-unsubscribe at mn-linux.org
> > > > > > > > For additional commands, e-mail:
tclug-list-help at mn-linux.org
> > > > > > > >
> > > > > > > >
> > > > > > >
> > > > > > >
> > > > > >
> > > ---------------------------------------------------------------------
> > > > > > > To unsubscribe, e-mail: tclug-list-unsubscribe at mn-linux.org
> > > > > > > For additional commands, e-mail: tclug-list-help at mn-linux.org
> > > > > > >
> > > > > > >
> > > > > >
> > > > > >
> > > > >
> > > ---------------------------------------------------------------------
> > > > > > To unsubscribe, e-mail: tclug-list-unsubscribe at mn-linux.org
> > > > > > For additional commands, e-mail: tclug-list-help at mn-linux.org
> > > > > >
> > > > > >
> > > > >
> > > > >
> > > >
> ---------------------------------------------------------------------
> > > > > To unsubscribe, e-mail: tclug-list-unsubscribe at mn-linux.org
> > > > > For additional commands, e-mail: tclug-list-help at mn-linux.org
> > > > >
> > > > >
> > > >
> > > >
> > >
> ---------------------------------------------------------------------
> > > > To unsubscribe, e-mail: tclug-list-unsubscribe at mn-linux.org
> > > > For additional commands, e-mail: tclug-list-help at mn-linux.org
> > > >
> > > >
> > >
> > >
> > > ---------------------------------------------------------------------
> > > To unsubscribe, e-mail: tclug-list-unsubscribe at mn-linux.org
> > > For additional commands, e-mail: tclug-list-help at mn-linux.org
> > >
> > >
> >
> >
> > ---------------------------------------------------------------------
> > To unsubscribe, e-mail: tclug-list-unsubscribe at mn-linux.org
> > For additional commands, e-mail: tclug-list-help at mn-linux.org
> >
> >
>
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: tclug-list-unsubscribe at mn-linux.org
> For additional commands, e-mail: tclug-list-help at mn-linux.org
>
>


---------------------------------------------------------------------
To unsubscribe, e-mail: tclug-list-unsubscribe at mn-linux.org
For additional commands, e-mail: tclug-list-help at mn-linux.org