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Date:      Wed, 19 Feb 2020 08:32:33 -0600
From:      Valeri Galtsev <galtsev@kicp.uchicago.edu>
To:        Doug Hardie <bc979@lafn.org>
Cc:        FreeBSD <freebsd-questions@freebsd.org>
Subject:   Re: Switching to backup Network
Message-ID:  <FE259796-0D7E-478A-862A-EF9D6B913425@kicp.uchicago.edu>
In-Reply-To: <F81D7D30-444B-4982-85BB-B2E3AED5C6BE@mail.sermon-archive.info>
References:  <64F39D12-E061-4726-B58E-943D61963944@mail.sermon-archive.info> <50d6c0e2-8e70-0743-1e9c-f4c36847a015@kicp.uchicago.edu> <F81D7D30-444B-4982-85BB-B2E3AED5C6BE@mail.sermon-archive.info>

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> On Feb 18, 2020, at 7:29 PM, Doug Hardie <bc979@lafn.org> wrote:
>=20
>> On 18 February 2020, at 12:25, Valeri Galtsev =
<galtsev@kicp.uchicago.edu> wrote:
>>=20
>>=20
>>=20
>> On 2020-02-18 14:19, Doug Hardie wrote:
>>> One of my clients has a machine running 12.1 that is connected via =
two different NICs to two different WANs.  He has drops from 2 different =
ISPs to provide redundancy. I have configured each of the DNS names with =
both IP addresses so that web access will switch over to the backup when =
the primary is down.  Setfib and pf are used to make that work.  That =
works fine (although there is a DNS timeout involved).  The problem is =
that all the servers on the machine talk out via the primary IP address. =
 While web access continues, the server initiated functions fail because =
the next hop is down.  Is there a way to switch everything over to the =
backup network in this case?  I don't find anything that enables =
automatic changes to the default network.
>>> Also, when the backup network goes down, the default network entry =
for setfib 1 route is deleted.  I have to manually enter that when it =
comes backup.  I am initially setting that in /etc/rc.local.  Is there a =
way to make it either remain, or be restored?
>>>=20
>>=20
>> I would look into link aggregation (lagg):
>>=20
>> =
https://www.freebsd.org/doc/en/books/handbook/network-aggregation.html
>>=20
>> I used that to make my FreeBSD laptop switch over from WiFi to =
ethernet interface when the last link is available. Worked neat for me.
>>=20
>> Valeri
>>=20
>=20
> Lagg looks neat, but my first setup didn't work.  I suspect the issue =
is the IP addresses.  Each of the two networks have quite different IPs. =
 Both are fixed IP addresses but from different allocations.  It appears =
that lagg requires the use of one IP for both networks.  All the =
examples use just one IP address for both networks.
>=20

I did not look into setting lagg for two ethernet interfaces, mine was =
for ethernet + WiFi. But they were definitely on different networks. =
Additional simplicity of my case was: both interfaces were DHCP clients =
(that took care of routing auto-magically). There was one =E2=80=9Chack=E2=
=80=9D I did in my case: I have a vague recollection I made both =
adapters under lagg have the same MAC address (by changing one of them), =
but that likely was due to my insufficient knowledge or laziness when I =
was setting it up. Expert probably will do it without that hack. I still =
have a feeling, one can do it for static IPs (my laptop configuration =
does work for interfaces on different networks), that=E2=80=99s why I =
suggested to look into that.

Hopefully, some lagg expert will offer you help. It may make sense to =
ask on freebsd-net list.

Valeri

> -- Doug
>=20
>=20
> _______________________________________________
> freebsd-questions@freebsd.org mailing list
> https://lists.freebsd.org/mailman/listinfo/freebsd-questions
> To unsubscribe, send any mail to =
"freebsd-questions-unsubscribe@freebsd.org"

++++++++++++++++++++++++++++++++++++++++
Valeri Galtsev
Sr System Administrator
Department of Astronomy and Astrophysics
Kavli Institute for Cosmological Physics
University of Chicago
Phone: 773-702-4247
++++++++++++++++++++++++++++++++++++++++




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