At Sat, 15 Nov 2025 08:12:17 +0700, Robert Elz <[email protected]> wrote: Subject: Re: Is it possible to completely disable ipv6 in NetBSD 10 > > | should work, shouldn't it ? > > No, it shouldn't - the two IFS related lines (first & last) > were a last minute addition, and a complete brain fade. > > Ignore those.
I mostly did ignore them -- I only tested the loop inside the command
substitution because I knew the outer loop worked from my previous tests
with the awk hack.
I wondered what they were for, and I didn't even copy them into my edits
and thought I'd look at them later, but your followup message arrived
before I had the chance.
Below is what I have now, and include some style adjustments to try to
match the rest of the script.
--
Greg A. Woods <[email protected]>
Kelowna, BC +1 250 762-7675 RoboHack <[email protected]>
Planix, Inc. <[email protected]> Avoncote Farms <[email protected]>
--- etc/rc.d/network.~1.85.~ 2021-03-07 15:43:39.000000000 -0800
+++ etc/rc.d/network 2025-11-15 21:14:54.774400241 -0800
@@ -30,7 +30,7 @@
have_inet6()
{
- /sbin/ifconfig lo0 inet6 >/dev/null 2>&1
+ [ $ip6mode != "off" ] && /sbin/ifconfig lo0 inet6 >/dev/null 2>&1
}
network_start()
@@ -43,14 +43,14 @@
network_start_domainname
network_start_loopback
have_inet6 &&
- network_start_ipv6_route
+ network_start_ipv6_route
[ "$net_interfaces" != NO ] &&
- network_start_interfaces
+ network_start_interfaces
network_start_aliases
network_start_defaultroute
network_start_defaultroute6
have_inet6 &&
- network_wait_dad
+ network_wait_dad
network_start_resolv
network_start_local
}
@@ -345,6 +345,35 @@
;;
esac
done
+ if [ $ip6mode = "off" ]; then
+ # disable IPv6 and remove the automatically added inet6
+ # addresses (specifically the automatically added
+ # "link-local" address.
+ #
+ # Note dhcpcd, if used, should only be used with "-4" in
+ # this mode in case the server answers with IPv6
+ # addresses.
+ #
+ # This is necessary to prevent the likes of X11 clients
+ # from trying to use IPv6 to connect to a neighbouring
+ # server, e.g. when mDNS answers have link-local
+ # addresses.
+ #
+ /usr/sbin/ndp -i $int disabled >/dev/null
+ for ip6addr in $(/sbin/ifconfig $int |
+ while read word arg stuff
+ do
+ case $word in
+ inet6)
+ printf '%s\n' "${arg}"
+ ;;
+ esac
+ done
+ )
+ do
+ /sbin/ifconfig $int inet6 delete "$ip6addr"
+ done
+ fi
configured_interfaces="$configured_interfaces $int"
done
echo "."
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