Posted: Fri Mar 18, 2022 1:36 Post subject: Changing the IPv6 DUID
I'm trying to see if I can get my ISP to give me a /60 instead of a /64. Word on the street says that once you request a /64, your DUID is locked in their system and will not give you a /60. So what I'm trying to do is change my DUID so that maybe, just maybe, my ISP will give me a decent IPv6 block.
From my understanding of how DD-WRT works with IPv6, it is not possible... the DUID is generated and when you adjust any of those parameters that would affect the DUID generation, then IPv6 does not work..
You can change DUID's but it is not support on DD-WRT...
Since the DUID is a function of the MAC address, you should be able to change your MAC address and a new DUID will be generated/used (ie after cleaning out the dhcp6c files)
if you look at /tmp/var/ on DD-WRT you can see where the dhcp6c_duid file is there but since this is regenerated on network restart ... you cannot change it.
When I try changing my MAC address IPv6 never picks up an address because there is a mistmatch on interface mapping.
Remember DD-WRT is not raw linux... it is a highly customized linux built using things like busybox... and the full flexibility is reduced to fit on these small embedded routers.
I dig a little about this, and you can change duid on dd-wrt.
First, on r49492 dhcp6c send 2 different duid/ClientId when you use the GUI in Setup/WAN Setup if you select DHCP authentication and fill DHCP IPv6 Client ID. So it's bugged.
Then I find that dhcp6c take the client id from /tmp/var/dhcp6c_duid. And you can change the content of this file.