Can dhcpd4.1-p1 Communicate with dhcpd3.1.3?

[Glenn Satchell]

On 11/01/10 01:13, Martin McCormick wrote:
> 	We want to transition from Version 3.1.3 to 4.1 without
> loosing our lease data base.
>
> 	There are presently two servers in the usual failover
> pair and the idea is to switch out the secondary first. It
> appears to be happy with the dhcpd.leases file so what would
> happen if we brought down the existing 3.1.3 secondary and then
> replaced it with the new 4.1 secondary? Would they sync up?
> Would the new secondary at least honor the existing leases? That
> would be good enough since the public would not have the chaos
> that results when the lease data base is lost.
>
> 	The plan is to replace the primary when the new
> secondary is functioning so there is no loss of lease
> continuity.
>
> 	Thank you for any suggestion.
>
> Martin McCormick

It is strongly recommended to run the identical version of dhcpd on both 
failover peers all the time. There is no guarantee that the failover 
protocol is compatible between different versions, and there was a 
significant change about that time.

This is from the dhcpd.conf man page, please note the last sentence:

DHCP FAILOVER
      This version of the ISC DHCP server supports the DHCP  fail-
      over  protocol  as  documented  in  draft-ietf-dhc-failover-
      12.txt.   This is not a final protocol document, and we have
      not done interoperability testing with other vendors' imple-
      mentations of this protocol, so you  must  not  assume  that
      this  implementation  conforms to the standard.  If you wish
      to use the failover protocol, make sure that  both  failover
      peers are running the same version of the ISC DHCP server.

The lease file and dhcpd.conf should be completely compatible between 
versions, so the suggested process is to shutdown both instances of 
dhcpd, install the new software and start them up.

The only systems that should notice this are new systems booting up that 
have not got an existing IP address. Renewing clients will just try 
again a bit later, without losing their current IP address.

You can test the lease file and dhcpd.conf with the new version using 
dhcpd -t and dhcpd -T.

-- 
regards,
-glenn
--
Glenn Satchell                            |  Miss 9: What do you
Uniq Advances Pty Ltd, Sydney Australia   |  do at work Dad?
mailto:glenn.satchell at uniq.com.au         |  Miss 6: He just
http://www.uniq.com.au tel:0409-458-580   |  types random stuff.