Ask Ubuntu is a question and answer site for Ubuntu users and developers. It only takes a minute to sign up.
Sign up to join this community
I would like to assign a static IPv6 address to my machine running Ubuntu Server 15 using DHCPv6. To do so, I need to know the DUID used by the DHCP client so I can assign the static IP to it in my network's DHCP server.
How can I find out which DUID is being used?
Ubuntu server calls dhclient with a few flags, but mostly default options, and it therefore defaults to a type 1 DUID-LLT DUID. Ubuntu desktop uses Network Manager which then calls dhclient with a type 4 DUID-UUID DUID.
For servers, it puts it in /var/lib/dhcp/dhclient6.......lease
For desktop, it puts it in /var/lib/NetworkManager/dhclient6.......lease
It's a weird string that looks like:
default-duid "\000\001\000\001\037\305\371\341\001\002\003\004\005\006"
Here's a short script you can use to convert it to a normal hex format duid.
Just run the script like:
./script '\000\001\000\001\037\305\371\341\001\002\003\004\005\006'
The script:
#!/bin/bash
printf $1 | hexdump -e '14/1 "%02x " "\n"' | sed 's/ /:/g'
14/1 to 18/1 in the script to account for the longer length of type 4 duid's. I think the script originally came from some redhat documentation and only had type 1 and type 3 duid's in mind.
Feb 22, 2017 at 7:57
-s 2 to skip some of the pre-amble, e.g.: hexdump -s 2 -e '14/1 "%02x " "\n"' /var/lib/dhcpv6/dhcp6c_duid
Jul 9, 2017 at 7:49
If you are using DHCP with ISC dhcpd look in:
/etc/dhcp/dhclient6.conf
If you are using dibbler as dhcp client check for the DUID in:
/var/lib/dibbler/client-duid
It might also be worth checking in /etc/dibbler/client.conf if any other bits are there.
