How to disable ipv6

[Zarif2000]

Hello.
I faced with a problem, I can't disable ipv6 completely on Armbian 23.05.1. Orange Pi PC.
Tried to use armbian-config to disable ipv6 in Network menu, but no luck, apps can use it at the moment

netstat -tulpn | grep :::    gives me

udp6       0      0 :::53                   :::*                                1134/pihole-FTL
udp6       0      0 :::111                  :::*                                1/init

Thanks in advance.

[TRS-80]

I disable it at my router (which is running OpenWrt).

[Zarif2000]

8 часов назад, TRS-80 сказал:

I disable it at my router (which is running OpenWrt).

My ISP doesn't provide ipv6. And also I user ip6tables and configured default policies on Armbian:

ip6tables -P INPUT DROP
ip6tables -P OUTPUT DROP
ip6tables -P FORWARD DROP

But I can't find out how to disable it completely.

I tried to add these lines to sysctl
net.ipv6.conf.all.disable_ipv6=1
net.ipv6.conf.default.disable_ipv6=1
net.ipv6.conf.lo.disable_ipv6=1

not working!

Next idea is to disable ipv6 via grub. But there is no /etc/default/grub file on Armbian.

Edited August 31, 2023 by Zarif2000

[Werner]

Tried blacklisting ipv6 kernel module?

[hexdump]

i think "ipv6.disable=1" added to the kernel cmdline should work

[Zarif2000]

01.09.2023 в 19:38, hexdump сказал:

i think "ipv6.disable=1" added to the kernel cmdline should work

Can you provide step-by-step guide please? Should I edit /boot/armbianEnv.txt ?

Edited September 12, 2023 by Zarif2000

[MichaIng]

sudo sed -i '/^extraargs=/$/ ipv6.disable=1/' /boot/armbianEnv.txt

 

Respectively add ipv6.disable=1 to the end of the "extraargs" line, separated with a space from other possible values.

However, this disables IPv6 support completely kernel-wise, which some software has problems with. E.g. the default Apache2 config on Debian comes with a vhost which dynamically binds to IPv4 and/or IPv6 addresses based on whether it is active on the interface or not. This syntax requires the kernel to at least understand IPv6, otherwise the webserver fails to start. So it is generally safer to only disable IPv6 on all interfaces, but keeping the kernel module active:

 

echo -e 'net.ipv6.conf.all.disable_ipv6=1\nnet.ipv6.conf.default.disable_ipv6=1' | tee /etc/sysctl.d/disable_ipv6.conf
sudo sysctl -p /etc/sysctl.d/disable_ipv6.conf

 

EDIT: Ah, now I see you basically tried this already. As this is universally functional on all Linux distros, it must actually work. Not sure how exactly to tried it, which exact command or config file? E.g. using the sysctl command itself is not boot-persistent, hence the config file.

Edited September 12, 2023 by MichaIng

[Zarif2000]

31.08.2023 в 09:33, Zarif2000 сказал:

I tried to add these lines to sysctl

As I was telling earlier, I used sysctl file.

 

12.09.2023 в 19:37, MichaIng сказал:

E.g. the default Apache2 config on Debian comes with a vhost which dynamically binds to IPv4 and/or IPv6 addresses based on whether it is active on the interface or not.

Sounds logical. And as far as I don't want to face with strange errors in a future, I'll let ipv6 in normal state.