Date: Mon, 08 Apr 2024 09:23:21 +0100 From: Roy Marples <roy@marples.name> To: "Anton Yudin" <contact@antonyudin.com> Cc: "freebsd-net" <freebsd-net@freebsd.org> Subject: Re: How to ignore a default route for one of the dhclient-ed interface? Message-ID: <18ebcce010c.c4bc5178125082.198975928787124826@marples.name> In-Reply-To: <CAAokbZ0t%2BYdU1bjfd%2ByhnTjUw82puWBJHs3rBxwS-%2BkTkERz%2Bg@mail.gmail.com> References: <CAAokbZ0t%2BYdU1bjfd%2ByhnTjUw82puWBJHs3rBxwS-%2BkTkERz%2Bg@mail.gmail.com>
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---- On Mon, 08 Apr 2024 04:16:47 +0100 Anton Yudin wrote ---=20
> =C2=A0 I'm running a FreeBSD 14 with two interfaces that use DHCP.=C2=A0=
I would like to make one of the interfaces to never set the default route.=
=C2=A0 Right now the first interface to be fully up sets the default route.
>=20
> =C2=A0 I tried to set the following in /etc/dhclient.conf
> ---------------8=C2=A0 interface "wan1" {=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 =
ignore routers;=C2=A0 }---------------8=C2=A0 but the default route still g=
ets set.
> =C2=A0 I ended up creating a /etc/dhclient-enter-hooks with a very hacky=
code that overrides the "route" command:---------------8<-----------------=
-------
> route() {
> =C2=A0 =C2=A0 =C2=A0 =C2=A0 if [ "X$interface" =3D "Xwan1" -a "X$2" =3D =
"Xdefault" =C2=A0]; then
> =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 echo "ignore rou=
te $1 $2 $3 $4" | logger -t "enter-hooks"
> =C2=A0 =C2=A0 =C2=A0 =C2=A0 else
> =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 /sbin/route $1 $=
2 $3 $4
> =C2=A0 =C2=A0 =C2=A0 =C2=A0 fi
> }---------------8
> Is there a better way of doing this?
Yes there is.
You can use dhcpcd (available in ports) instead where you can prefer an int=
erface by metric.
When both interfaces have a DHCP lease, dhcpcd will prefer the lowest metri=
c and adjust routing and everything else accordingly.
Assuming you have wan0 and wan1 and are ignoring wan1 the chances are that =
dhcpcd will just work for you out of the box.
Otherwise you can tell dhcpcd your preference like so:
interface eth0
metric 1
Here, eth0 will take preference other any other interface.
OR
You can also remove the option from the DHCP packet before processing
interface wan1
nooption routers
Hope this helps
Roy
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