4.1.1 lease duplicate

Wim Vandersmissen Wim.Vandersmissen at icts.kuleuven.be
Wed May 19 15:03:36 UTC 2010


Hi,

Run a tcpdump on one of your servers, maybe you got clients where the 'secs' field of the DHCPDISCOVER header is greater than 3 (as specified by "load balance max seconds 3"). If that's the case, the load-balancing is disabled and both servers will offer an IP, which will cause a 'is duplicate' message.

Maybe same problem as I had (see https://lists.isc.org/pipermail/dhcp-users/2010-April/011298.html )

Kind regards,

--Wim


> -----Original Message-----
> 
> Hi !
> 
> 
> We are seeing lot's of duplicate in log files, and users also reports
> duplicate
> ip addresses. Here is some of our config and logs :
> 
> Internet Systems Consortium DHCP Server 4.1.1
> 
> authoritative;
> ddns-update-style none;
> ddns-updates off;
> server-identifier dhcp1.domain.com;
> option domain-name "domain.com";
> option domain-name-servers 10.0.0.3, 10.0.0.1;
> default-lease-time 7200;
> max-lease-time 21600;
> option netbios-node-type 2;
> always-broadcast on;
> one-lease-per-client true;
> deny duplicates;
> ignore declines;
> ignore client-updates;
> 
> failover peer "dhcp" {
>    primary;
>    address 10.0.0.3;
>    port 647;
>    peer address 10.0.0.1;
>    peer port 647;
>    max-response-delay 60;
>    max-unacked-updates 10;
>    load balance max seconds 3;
>    mclt 600;
>    split 128;
> }
> 
> subnet 10.8.32.0 netmask 255.255.255.0 {
>          option domain-name "domain.com";
>          option domain-name-servers 10.0.0.3, 10.0.0.1;
>          option broadcast-address 10.8.32.255;
>          option routers 10.8.32.1;
>          pool {
>                  failover peer "dhcp";
>                  deny dynamic bootp clients;
>                  range 10.8.32.12 10.8.32.249;
>          }
> }
> 
> 
> May 18 22:41:37 dhcp-1 dhcpd: DHCPDISCOVER from 00:23:12:02:e1:88 via
> 10.8.32.1
> May 18 22:41:38 dhcp-1 dhcpd: DHCPOFFER on 10.8.32.227 to
> 00:23:12:02:e1:88 via 10.8.32.1
> May 18 22:41:39 dhcp-1 dhcpd: DHCPDISCOVER from 00:23:12:02:e1:88 via
> 10.8.32.1
> May 18 22:41:39 dhcp-1 dhcpd: DHCPOFFER on 10.8.32.227 to
> 00:23:12:02:e1:88 via 10.8.32.1
> May 18 22:41:41 dhcp-1 dhcpd: DHCPDISCOVER from 00:23:12:02:e1:88 via
> 10.8.32.1
> May 18 22:41:41 dhcp-1 dhcpd: DHCPOFFER on 10.8.32.227 to
> 00:23:12:02:e1:88 via 10.8.32.1
> May 18 22:41:46 dhcp-1 dhcpd: DHCPDISCOVER from 00:23:12:02:e1:88 via
> 10.8.32.1
> May 18 22:41:46 dhcp-1 dhcpd: DHCPOFFER on 10.8.32.227 to
> 00:23:12:02:e1:88 via 10.8.32.1
> May 18 22:41:47 dhcp-1 dhcpd: DHCPREQUEST for 10.8.32.227 (10.0.0.3)
> from 00:23:12:02:e1:88 via 10.8.32.1
> May 18 22:41:47 dhcp-1 dhcpd: DHCPACK on 10.8.32.227 to
> 00:23:12:02:e1:88 via 10.8.32.1
> May 18 22:41:48 dhcp-1 dhcpd: DHCPREQUEST for 10.8.32.227 (10.0.0.3)
> from 00:23:12:02:e1:88 via 10.8.32.1
> May 18 22:41:48 dhcp-1 dhcpd: DHCPACK on 10.8.32.227 to
> 00:23:12:02:e1:88 via 10.8.32.1
> May 18 22:41:47 dhcp-1 dhcpd: DHCPREQUEST for 10.8.32.227 (10.0.0.3)
> from 00:23:12:02:e1:88 via 10.8.32.1: lease owned by peer
> May 18 22:41:48 dhcp-1 dhcpd: DHCPREQUEST for 10.8.32.227 (10.0.0.3)
> from 00:23:12:02:e1:88 via 10.8.32.1
> May 18 22:41:48 dhcp-1 dhcpd: DHCPACK on 10.8.32.227 to
> 00:23:12:02:e1:88 via 10.8.32.1
> 
> 
> authoritative;
> ddns-update-style none;
> ddns-updates off;
> server-identifier dhcp2.domain.com;
> option domain-name "domain.com";
> option domain-name-servers 10.0.0.3, 10.0.0.1;
> default-lease-time 7200;
> max-lease-time 21600;
> option netbios-node-type 2;
> always-broadcast on;
> one-lease-per-client true;
> deny duplicates;
> ignore declines;
> ignore client-updates;
> 
> failover peer "dhcp" {
>    secondary;
>    address 10.0.0.1;
>    port 647;
>    peer address 10.0.0.3;
>    peer port 647;
>    max-response-delay 60;
>    max-unacked-updates 10;
>    load balance max seconds 3;
> }
> 
> subnet 10.8.32.0 netmask 255.255.255.0 {
>          option domain-name "domain.com";
>          option domain-name-servers 10.0.0.3,10.0.0.1;
>          option broadcast-address 10.8.32.255;
>          option routers 10.8.32.1;
>          pool {
>                  failover peer "dhcp";
>                  deny dynamic bootp clients;
>                  range 10.8.32.12 10.8.32.249;
>          }
> }
> 
> 
> May 18 22:41:37 dhcp-2 dhcpd: DHCPDISCOVER from 00:23:12:02:e1:88 via
> 10.8.32.1: load balance to peer dhcp
> May 18 22:41:39 dhcp-2 dhcpd: DHCPDISCOVER from 00:23:12:02:e1:88 via
> 10.8.32.1
> May 18 22:41:40 dhcp-2 dhcpd: DHCPOFFER on 10.8.32.76 to
> 00:23:12:02:e1:88 via
> 10.8.32.1
> May 18 22:41:41 dhcp-2 dhcpd: DHCPDISCOVER from 00:23:12:02:e1:88 via
> 10.8.32.1
> May 18 22:41:41 dhcp-2 dhcpd: DHCPOFFER on 10.8.32.76 to
> 00:23:12:02:e1:88 via
> 10.8.32.1
> May 18 22:41:46 dhcp-2 dhcpd: DHCPDISCOVER from 00:23:12:02:e1:88 via
> 10.8.32.1
> May 18 22:41:46 dhcp-2 dhcpd: DHCPOFFER on 10.8.32.76 to
> 00:23:12:02:e1:88 via
> 10.8.32.1
> May 18 22:41:47 dhcp-2 dhcpd: uid lease 10.8.32.76 for client
> 00:23:12:02:e1:88
> is duplicate on 10.8.32.0/24
> 
> --
> Regards;
> 
>    Roar Pettersen
>    Universitetet i Bergen -  The University of Bergen
> _______________________________________________
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> dhcp-users at lists.isc.org
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