failover compatibility

Wed Sep 5 06:26:58 UTC 2012

Hi,

Again, thanks. My method will have to be a little different since oldx
and newx are the same box but I get the idea. The IP addresses will be
the same as we're allocating through a WAN so using ip-helpers.

One last, probably dumb question, if I may. What does a client do if no
DHCP servers are available? Does it keep its address or drop it and go
off the air?

Colin
--
Colin Campbell
Security Specialist
Public Safety Network Management Centre
p: (07) 3008 4851
f: (07) 3008 4799
e: campbell.colind at police.qld.gov.au

> -----Original Message-----
> From:
dhcp-users-bounces+campbell.colind=police.qld.gov.au at lists.isc.org
>
[mailto:dhcp-users-bounces+campbell.colind=police.qld.gov.au at lists.isc.o
rg]
> On Behalf Of Glenn Satchell
> Sent: Wednesday, 5 September 2012 4:20 PM
> To: Users of ISC DHCP
> Subject: RE: failover compatibility
> 
> (b) copy the leases file is preferable. Do this after shutting down
dhcpd.
> 
> The clients hold the lease information too, so they need to match up.
> 
> It's been a while since I've done this, but essentially you need to
copy
> each one.
> 
> 1. Shut down old1
> 2. Copy dhcpd.conf and dhcpd.leases to new1.
> 3. Start new1
> 4. Shut down old2
> 5. Copy dhcpd.conf and dhcpd.leases to new2
> 6. Start new 2
> 
> May need to swap steps 3 and 4.
> 
> Are you using new dhcp servers? Will they have the same or new IPs? If
the
> new servers are running on new ip addresses then all clients will need
to
> wait for their lease to expire, then they will go back to discover the
new
> dhcp servers. On the other hand if the new servers have the same IP
> addresses as the old servers then the clients will contact them
directly
> to renew existing leases. Either works ok as long as the leases file
is
> copied to the new server so that it can issue the same IP address the
> client had before.
> 
> regards,
> -glenn
> 
> On Wed, September 5, 2012 2:30 pm, Campbell.ColinD at police.qld.gov.au
wrote:
> > Hi,
> >
> > Thanks for that. That brings a new quandary.
> >
> > I can't upgrade both servers simultaneously. I have to do one at a
time.
> > In doing so, I plan on shutting one down, upgrading it, restoring
the
> > configs, shutting down the other old server and doing something with
the
> > leases on the new server. That something could be:
> >
> > a) let the new server create a new leases file, or
> > b) copy the leases file from the still-active old server
> >
> > Is (a) or (b) preferable? If neither, what is the correct procedure?
> >
> > Colin
> > --
> > Colin Campbell
> > Security Specialist
> > Public Safety Network Management Centre
> > p: (07) 3008 4851
> > f: (07) 3008 4799
> > e: campbell.colind at police.qld.gov.au
> >
> >
> >> -----Original Message-----
> >> From:
> > dhcp-users-bounces+campbell.colind=police.qld.gov.au at lists.isc.org
> >>
> >
[mailto:dhcp-users-bounces+campbell.colind=police.qld.gov.au at lists.isc.o
> > rg]
> >> On Behalf Of Glenn Satchell
> >> Sent: Wednesday, 5 September 2012 2:11 PM
> >> To: Users of ISC DHCP
> >> Subject: Re: failover compatibility
> >>
> >> No. The failover protocol changed somewhere in the 3.1 to 4.x
range.
> >> Details would be in the RELNOTES file distributed with the source.
> >>
> >> Essentially you need to shutdown and upgrade both failover hosts at
> > the
> >> same time. You can pre-check the format of dhcpd.conf and
dhcpd.leases
> >> using dhcpd -t and dhcpd -T to see if there are any issues wit the
new
> >> version. In general, the files *should* be compatible with all
newer
> >> versions.
> >>
> >> regards,
> >> -glenn
> >>
> >> On Wed, September 5, 2012 8:24 am,
Campbell.ColinD at police.qld.gov.au
> > wrote:
> >> > Hi,
> >> >
> >> > Will a 3.0.5 server form a failover pair with a 4.x server? This
> > would
> >> > be a temporary arrangement during a server pair upgrade.
> >> >
> >> > Colin
> >> > --
> >> > Colin Campbell
> >> > Security Specialist
> >> > Public Safety Network Management Centre
> >> > p: (07) 3008 4851
> >> > f: (07) 3008 4799
> >> > e: campbell.colind at police.qld.gov.au
> >> >
> >> >
> >> >
> >
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