DHCPv6

General Discussion
1

Hello!
Since I am using the dietpi devices as servers I needed a static IP, but I failed miserably to configure it in /etc/network/interfaces or interfaces.d
Hence I tried my luck with dhcp6 and it seems to work fine:

dietpi@odroid:[~]$ ps auxw | grep dhcp
root       534  0.0  0.2   6236  2260 ?        Ss   Φεβ23   0:00 /sbin/dhclient -4 -v -i -pf /run/dhclient.eth0.pid -lf /var/lib/dhcp/dhclient.eth0.leases -I -df /var/lib/dhcp/dhclient6.eth0.leases eth0
root      1180  0.0  0.2   6236  2284 ?        Ss   Φεβ23   0:00 /sbin/dhclient -6 -v -i -pf /run/dhclient6.eth0.pid -lf /var/lib/dhcp/dhclient6.eth0.leases -I -df /var/lib/dhcp/dhclient6.eth0.leases eth0

Also notice that the dhcp client for ipv4 is using dhclient6.eth0.leases, not sure if this was accidental or intended.
The main question is how can I make this change permanent so it doesn’t get overwritten in some future upgrade?
Is it possible to include it in a future release as well as an option?
Thank you!

2

Hi,

I would recommend to use dietpi-config tool to make changes on your network interfaces. There you can set a STATIC IP.

3

It is not obvious how to input the IPv6 addresses/mask/gateway/nameservers.
Am I supposed to input the ipv6 address after the ipv4, separated with space or comma?

               ●─ DHCP/STATIC IP ──────────────────────● 
Change Mode    : [STATIC]                                
Copy           : Copy current address to "Static"        
Static Ip      : [10.0.2.2 fd00:bbbb::2]                 
Static Mask    : [255.255.255.0 64]                      
Static Gateway : [10.0.2.1 fd00:bbbb::1]                 
Static DNS     : [127.0.0.1 ::1]                         
               ●─ Additional Options ──────────────────●

Just to be clear. IPv6 is enabled and works fine with SLAAC. What I want is to have dhcp6 client or to be able to set static IP.

4

Than we misunderstood.

Within the dietpi-config, STATIC IP address configuration you could specify for IPv4 addresses only. IPv6, you just simply need to activate.

Using SLAAC, the IPv6 network listens for a Router Advertisement (RA) from the host and then assigns a 64-bit prefix. The last 64 bits of the address are derived in a process in which the host device essentially self-determines its address. so it’s nearly static as the host is creating it’s own address.

Is there a reason to use IPv6 on a local network? usually IPv4 should be fine for privat use.

5

The only thing that activates Dietpi is SLAAC and I mentioned that SLAAC is working fine. But this is not my question.
If there is no easy way to apply a static IPv6, I can live with DHCPv6. It works with the command I provided in the first post. I want to know if this can be enabled somehow in Dietpi or where to place it so it doesn’t get overwritten and to start when the interface goes down/up.

Because I am using IPv6 in all my devices and I have delegated prefix from my ISP.

6

Adding

iface eth0 inet6 dhcp

in

/etc/network/interfaces

does the work.
So I guess by adding a line

iface eth$ETH_DEV_INDEX inet6 $eth_dhcp_static_text

in position 2396 (and in 2404 for wifi “iface wlan$WIFI_DEV_INDEX inet $wifi_dhcp_static_text” ) in

/boot/dietpi/dietpi-config

under Network_ApplyChanges() function will make the change permanent for the future.

1 Like
7

Can it be added in the next version?
I don’t think it hurts to have DHCP6 as well and not just SLAAC.

8

Yes full IPv6 support, including DHCPv6, is planned: https://github.com/MichaIng/DietPi/projects/1
Will be the first thing I start working on after v6.29 release.

9

Splendid! Thank you Michal!

10

I know this is a very old topic, but just in case someone has the same problem, I found the solution on the debian website.

It states that you need to modify your /etc/network/interfaces file and add something like this:

    iface eth0 inet6 static
        address 2001:db8::c0ca:1eaf/64
        gateway 2001:db8::1ead:ed:beef
11

Thanks for the intervention. :slight_smile:
I remember I incorporated the changes here and it worked fine. I am not sure if in the meantime it became mainstream from @MichaIng .

12

nope, static IPv6 is not part of our standard implementation.

13

I btw recommend to add custom config blocks via dedicated config files, e.g.

cat << '_EOF_' > /etc/network/interfaces.d/eth0-ipv6.conf
iface eth0 inet6 static
address 2001:db8::c0ca:1eaf/64
gateway 2001:db8::1ead:ed:beef
_EOF_
ifup --force eth0
2 Likes
14

So… It’s still a issue like 2 years after ? Because i still don’t have dhcpv6 on my dietpi on the last upate so… Hum… .when ?

Because a simple raspbian have it, so what you do ? You said you just “put scripts” on it but at the end it just… .miss stuffs ?

Why remove DHCPv6 on default installation on a os that for… network stuffs ?

I don’t understand. Also : having a simple doc to just… activate DHCPv6 is possible, too ?

15

If you are a power user then DietPi is maybe not the right choice for you. DietPi tries to keep things simple, most of the useres probably don’t even use IPv6 and if they use, also only a small subset needs DHCPv6, most are fine with SLAAC and RA.

So if you know how to do it in Debian (or RPi OS) you can also do it the same way on DietPi. It’s not removed, the script just don’t care about. But feel free to edit /etc/network/interfaces to your likings and add a config for dhcp6.

If it’s so simple feel free to contribute on GitHub, even when you just extend the docs for the simple part of how to use IPv6 with DHCPv6 :slight_smile:

16

To get the address from DHCP6

cat << EOF > /etc/network/interfaces.d/ipv6.conf
iface eth0 inet6 dhcp
        autoconf 1
        accept_ra 2
EOF

Although I think that in 2024 we should not be discussing if IPv6 is used or not, if it is for advanced users etc.
It is a minor thing to add a config file.

17

Ping @MichaIng

18

Especially as power user, one should not have any issues adding a custom config file or edit one, which can be done on DietPi like on any other Debian or Debian-based system :wink:.

But yeah, better use a drop-in config like trendy suggested, so even when using dietpi-config to change network settings, it will survive.

DHCPv6 is a very rare think that is usually not required thanks to SLAAC. IPv6 is generally enabled via SLAAC OOTB on DietPi, as long as the local network supports it. The question is @tr1p0p whether you really need DHCPv6 to setup IPv6 addresses in you LAN. I can imagine use cases, but I can’t remember ever facing one.

Static IPv6 addresses generally cannot work, since they naturally need to have the public IPv6 prefix, which is given by your ISP and are hence not chosen.