Help with server configuration dhcpd6.conf

John.Gibbins at John.Gibbins at
Mon Jan 17 23:41:14 UTC 2011

Try changing the subnet6 reference to remove the trailing "1".  Ie subnet6 2002:c706:01ef:0001::1/64 => subnet6 2002:c706:01ef:0001::/64.

The trailing one stops it being a valid /64 network address.  The interface address part should be all zeros.

John Gibbins
IT Security Operations (and IPv6 Evangelist)
CSIRO Information Management & Technology (IM&T)
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From: at [ at] On Behalf Of Dan Tran
Sent: Tuesday, 18 January 2011 10:21 AM
To: dhcp-users at
Cc: Dan Tran
Subject: Help with server configuration dhcpd6.conf

I'm using isc-dhcpd-4.1.1

My dhcpd6.conf is as following:

default-lease-time 600;
max-lease-time 7200;
subnet6 2002:c706:01ef:0001::1/64 {
     range6 2002:c706:01ef:0001:8000::/65; }

The interface config is as following:

ixint1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOW
    link/ether 00:00:02:70:78:bf brd ff:ff:ff:ff:ff:ff
    inet6 2002:c706:1ef:1::1/64 scope global
       valid_lft forever preferred_lft forever
    inet6 fe80::200:2ff:fe70:78bf/10 scope link
       valid_lft forever preferred_lft forever

When I tried running dhcpd server I have Add/mask length mismatch error as following:

# dhcpd -6 ixint1
Internet Systems Consortium DHCP Server 4.1.1
Copyright 2004-2010 Internet Systems Consortium.
All rights reserved.
For info, please visit
Wrote 0 leases to leases file.
subnet_number():inet.c:52: Addr/mask length mismatch.

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Please help with a working configuration for dhcpd6.conf


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