blog.crox.net (Entries tagged as ipv6)

IPv6 Neighbor discovery

nospam@example.com (crox) — Wed, 11 Jul 2018 06:12:00 +0000

Discover/list other hosts:

ping6 -I eth0 ff02::1
ip -6 neigh show

To connect to a host using the link-local address you need to specify which interface to use (see "zone index"):

ssh -6 fe80::a00:aaaa:bbbb:cccc%eth0

Grafana auto login

nospam@example.com (crox) — Tue, 26 Dec 2017 19:57:00 +0000

The solution described here works for me.

I did the following on the internal host where Grafana is installed:

Configured Apache (on port 80) as reverse proxy to Grafana (on port 3000)
Setup the virtualhost to add/set the required headers to login automatically as user admin

Relevant section from /etc/grafana/grafana.ini:

[auth.proxy]
enabled = true
;header_name = X-WEBAUTH-USER
;header_property = username
auto_sign_up = false

Apache config extract (you will need to enable mod_proxy, mod_proxy_http and mod_headers for this to work):

<VirtualHost *:80>
        ProxyPreserveHost On
        ProxyRequests Off
        ProxyPass / http://localhost:3000/
        ProxyPassReverse / http://localhost:3000/
        RequestHeader set "X-WEBAUTH-USER" "admin"
</VirtualHost>

On a separate Apache instance exposed to more networks I did the following:

Configured Apache as reverse proxy to the internal instance
Restricted access from specific IP addresses
Setup a rule to redirect requests to the root of the website (and only those) to a specific dashboard

This is how the Apache config looks like (requires mod_proxy, mod_proxy_http and mod_alias; IP addresses, host names etc. changed)

<VirtualHost *:80>
        ServerName sub.example.org
        ServerAlias www.sub.example.org
        <Location />
            Require ip 192.0.2.0/24
            Require ip 203.0.113.0/24
            Require ip 2001:0db8:85a4::/64
            Require ip 2001:0db8:85a5::/64
            RedirectMatch ^/$ /dashboard/db/mydashboard
        </Location>
        ProxyPreserveHost On
        ProxyRequests Off
        ProxyPass / http://[2001:0db8:85a3::aaaa:8a2e:0370:7334]/
        ProxyPassReverse / http://[2001:0db8:85a3::aaaa:8a2e:0370:7334]/
</VirtualHost>

Using a public IPv6 address on the internal host allows the whole thing to work with just a few firewall rules, without the need to mess with NAT or a VPN.

Enable IPv6 on OSMC (wired and wireless)

nospam@example.com (crox) — Sat, 01 Aug 2015 22:14:00 +0000

Despite having read the opposite, it looks like IPv6 is disabled by default on the latest OSMC release (2015.06-1). I've tried adding a sysctl.d file to set /proc/sys/net/ipv6/conf/eth0/disable_ipv6 to 0, but this did not help. It worked only when I ran the command manually. By going through numerous forum posts I eventually found out that you need to use the connmanctl CLI tool:

root@osmc:~# connmanctl
connmanctl> services
*AO Wired                ethernet_b827ebaabbcc_cable
connmanctl> config ethernet_b827ebaabbcc_cable --ipv6 auto preferred
connmanctl> quit
root@osmc:~#

This enables IPv6 with autoconfiguration, turns on Privacy Extensions and prefers these ephemeral addresses over the autoconfigured ones.

The same command works for wireless as well, you just need to select the appropriate interface (the service name will start with wifi_).

"help" will display basic usage info.

If for some reason you would like to disable IPv6, the command would be "config ... --ipv6 off".

now with IPv6

nospam@example.com (crox) — Mon, 30 Jan 2012 19:23:26 +0000

In anticipation of World IPv6 Launch Day (6 June 2012), this website is now fully reachable over IPv6.

IPv6 test websites

nospam@example.com (crox) — Sun, 22 Jan 2012 23:33:00 +0000

http://ipv6-test.com/ (also has a speed test, shows your MAC address when available)

http://test-ipv6.com/ (provides detailed technical info and "readiness score")

http://whatismyv6.com/ (IPv4 only, IPv6 only)

http://www.whatismyipv6.net/ (provides traceroute and ping, also suports IPv4)

Enabling IPv6 Privacy Extensions on all interfaces (Ubuntu Linux, may work for other distros too)

nospam@example.com (crox) — Sun, 22 Jan 2012 23:22:01 +0000

According to the Wikipedia IPv6 article, Privacy extensions are, except for the Windows platform and Mac OS X since 10.7 as well as iOS since version 4.3, not enabled by default.

In theory, one can enable the IPv6 Privacy Extensions on all interfaces at once using sysctl like this:

sudo sysctl net.ipv6.conf.all.use_tempaddr=2

However, this currently doesn't work as expected, so I'm using this one-liner in /etc/rc.local:

for IF in `/bin/ls /proc/sys/net/ipv6/conf/*/use_tempaddr` ; do echo 2 > $IF ; done

This also sets "use_tempaddr" for "default", which means it should also apply to interfaces added to the system afterwards.

A simple check to verify that the new configuration is working: ipv6-test.com will print your MAC address when available...

See also: Linux Kernel Bug 11655