DHCPv6 query

Mon Apr 9 12:59:48 UTC 2012

In the test-case that you setup, the client is going to accept whichever packet gets there first. It could have just as easily got a packet from server 2 if that packet had arrived first. If you shut of server 1 long enough that the client's lease runs out, it will get an address from server 2. 

There is no failover support yet in DHCPv6 (although there is a draft for it that is currently worming its way through the IETF). If you have a relay agent in the middle, you can set priorities on which server should have preference etc... 

----- Original Message -----

> From: "ameen shajahan" <ameen.shajahan at wipro.com>
> To: dhcp-users at lists.isc.org
> Sent: Monday, April 9, 2012 5:59:37 AM
> Subject: DHCPv6 query

> Hi all,
> I need clarification for a below output.
> Consider the scenario, I have run two dhcpv6 servers in two different
> eservers.
> Server1 subnet is 3ffe:501:ffff:105::15
> Server2 subnet is 3ffe:501:ffff:116::15
> These two servers connected to 1 switch , from that switch its
> connected to Windows7PC(client)

> 
> 
> 

> Cisco switch
> 
> 

> Client(Windows7PC)
> 

> DHCPV6 server1
> DHCPv6 server 2

> Ran the two servers at a sametime , Client got the IPv6 address in
> the subnet range 3ffe:501:ffff:105::15 not in 3ffe:501:ffff:116::15
> Then I stopped both the server , restarted both the servers again.
> Again Client getting the IPv6 address in the range
> 3ffe:501:ffff:105::14 not in 3ffe:501:ffff:116::15
> Conceptuall it could be correct , because client get a single IP
> address at a time.
> I would like to know , why its not assigning to this
> range(3ffe:501:ffff:116::15) eventhough I restarted both the servers
> 4 to 5 times.
> Is there any priority following for assigning IPv6 address.
> What could be the reason .
> Please let me know.

> Output 1(IP assigned output)

> Jan 13 03:22:30 ameen daemon.info dhcpd: Solicit message from
> fe80::c8b0:62f6:fd72:7074 port 546, transaction ID 0xDCE659
> Jan 13 03:22:30 ameen daemon.debug dhcpd: Picking pool address
> 3ffe:501:ffff:105::15
> Jan 13 03:22:30 ameen daemon.info dhcpd: Sending Advertise to
> fe80::c8b0:62f6:fd72:7074 port 546
> Jan 13 03:22:31 ameen daemon.info dhcpd: Request message from
> fe80::c8b0:62f6:fd72:7074 port 546, transaction ID 0xDCE659
> Jan 13 03:22:31 ameen daemon.info dhcpd: Sending Reply to
> fe80::c8b0:62f6:fd72:7074 port 546

> Jan 13 03:23:25 ameen daemon.info dhcpd: Release message from
> fe80::c8b0:62f6:fd72:7074 port 546, transaction ID 0x74B40B
> Jan 13 03:23:25 ameen daemon.info dhcpd: Client
> 00:01:00:01:14:d3:bd:62:90:fb:a6:ec:74:35 releases address
> 3ffe:501:ffff:105::15, which is not leased to it.
> Jan 13 03:23:25 ameen daemon.info dhcpd: Sending Reply to
> fe80::c8b0:62f6:fd72:7074 port 546

> Output2(unassigned IP output)

> feb 20 03:56:05 ameen daemon.info dhcpd: Solicit message from
> fe80::c8b0:62f6:fd72:7074 port 546, transaction ID 0xDCE659
> Feb 20 03:56:05 ameen daemon.debug dhcpd: Picking pool address
> 3ffe:501:ffff:116::15
> Feb 20 03:56:05 ameen daemon.info dhcpd: Sending Advertise to
> fe80::c8b0:62f6:fd72:7074 port 546
> Feb 20 03:56:06 ameen daemon.notice dhcpd: SFR: Init = 1C71 UP = 9C95
> LOW = 9C4C
> Feb 20 03:56:06 ameen daemon.info dhcpd: Request message from
> fe80::c8b0:62f6:fd72:7074 port 546, transaction ID 0xDCE659
> Feb 20 03:56:06 ameen daemon.debug dhcpd: Discarding Request from
> fe80::c8b0:62f6:fd72:7074; not our server identifier (CLIENTID
> 00:01:00:01:14:d3:bd:62:90:fb:a6:ec:74:35, SERVERID
> 00:01:00:01:16:a2:5f:70:00:60:43:60:ca:99, server DUID
> 00:01:00:01:16:d4:80:52:00:60:43:
> Feb 20 03:56:17 ameen daemon.notice dhcpd: SFR: Init = 1C71 UP = 9C95
> LOW = 9C4C

> Feb 20 03:57:01 ameen daemon.info dhcpd: Release message from
> fe80::c8b0:62f6:fd72:7074 port 546, transaction ID 0x74B40B
> Feb 20 03:57:01 ameen daemon.debug dhcpd: Discarding Release from
> fe80::c8b0:62f6:fd72:7074; not our server identifier (CLIENTID
> 00:01:00:01:14:d3:bd:62:90:fb:a6:ec:74:35, SERVERID
> 00:01:00:01:16:a2:5f:70:00:60:43:60:ca:99, server DUID
> 00:01:00:01:16:d4:80:52:00:60:43:
> Feb 20 03:57:12 ameen daemon.notice dhcpd: SFR: Init = 1C71 UP = 9C95
> LOW = 9C4C

> Regards,
> Ameen S

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