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Today's Topics:
1. Adding and Removing interfaces dynamically (Shweta Jogi)
2. dhclient and custom Linux routing tables (VRF) (Mateusz Viste)
3. Re: dhclient and custom Linux routing tables (VRF)
(Thomas Markwalder)
4. Re: dhclient and custom Linux routing tables (VRF) (Tony Finch)
----------------------------------------------------------------------
Message: 1
Date: Thu, 6 Jun 2019 12:40:35 +0000
From: Shweta Jogi <shweta.j...@sophos.com>
To: "dhcp-users@lists.isc.org" <dhcp-users@lists.isc.org>
Subject: Adding and Removing interfaces dynamically
Message-ID: <72203d49-61a1-41bf-afe7-2aed9ea7c...@sophos.com>
Content-Type: text/plain; charset="utf-8"
Hi All,
I am dynamically adding and removing interfaces in DHCPv4 using same logic
written in discover_interfaces.
Everything works fine, but as soon as I move my logic of adding and removing
interfaces into a thread, those interfaces are not listening for broadcast
packets, but they are able to process unicast packets.
Anyone have any idea what can be the reason ? And clue will be really
appreciated.
Regards,
Shweta Jogi
________________________________
Sophos Technologies Private Limited Regd. Office: Sophos House, Saigulshan
Complex, Beside White House, Panchvati Cross Road, Ahmedabad - 380006, Gujarat,
India CIN: U72200GJ2006PTC047857
Sophos Ltd, a company registered in England and Wales number 2096520, The
Pentagon, Abingdon Science Park, Abingdon, OX14 3YP, United Kingdom.
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Message: 2
Date: Fri, 7 Jun 2019 13:23:29 +0200
From: Mateusz Viste <mate...@viste.fr>
To: dhcp-users@lists.isc.org
Subject: dhclient and custom Linux routing tables (VRF)
Message-ID: <e0339f19-b426-d25c-824e-bf4bd12ec...@viste.fr>
Content-Type: text/plain; charset=utf-8; format=flowed
Hello all,
I am trying to use the ISC dhclient with Linux VRFs, where each VRF is
assigned a custom Linux routing table. Typically, like this:
# ip link add vrf1 type vrf table 10
# ip link set eth0 master vrf1
# ip link set vrf1 up
# dhclient eth0
Unfortunately, dhclient populates the default Linux routing table with
the default gateway it receives, instead of adding it to the VRF's
routing table:
# ip route show
default via 10.0.2.2 dev eth0
# ip route show table 10
10.0.2.0/24 dev eth0 proto kernel scope link src 10.0.2.15
local 10.0.2.15 dev eth0 proto kernel scope host src 10.0.2.15
I have read dhclient's documentation, and did not find any mention of
either VRFs or custom routing tables... Have I missed some obvious trick
here?
Mateusz
------------------------------
Message: 3
Date: Fri, 7 Jun 2019 07:41:30 -0400
From: Thomas Markwalder <tm...@isc.org>
To: dhcp-users@lists.isc.org
Subject: Re: dhclient and custom Linux routing tables (VRF)
Message-ID: <a3819f1a-58e6-80bc-7832-6fbda77d6...@isc.org>
Content-Type: text/plain; charset=utf-8; format=flowed
Configuring interfaces and routing tables and what not are extremely OS
implementation dependent and as such dhclient itself has never directly
changed any of these things.? Operations like this are actually carried
out by a helper shell script which dhclient invokes at various stages of
operation and through out the life cycle of asking for, obtaining, and
releases leases. Prior to each invocation it sets numerous environment
variables with pertinent values like the old ip address, new ip address
etc.? The script is expected to configure interfaces and other OS/site
specific operations, but is generally free to do whatever it wishes, so
long as it returns the appropriate exit statuses.
Refer to? man 8 dhclient-script for details.? You can specify a
customized script via command line, or more properly, you can supply
enter and exit "hook" scripts as described in the man-page.
On 6/7/19 7:23 AM, Mateusz Viste wrote:
> Hello all,
>
> I am trying to use the ISC dhclient with Linux VRFs, where each VRF is
> assigned a custom Linux routing table. Typically, like this:
>
> # ip link add vrf1 type vrf table 10
> # ip link set eth0 master vrf1
> # ip link set vrf1 up
> # dhclient eth0
>
> Unfortunately, dhclient populates the default Linux routing table with
> the default gateway it receives, instead of adding it to the VRF's
> routing table:
>
> # ip route show
> default via 10.0.2.2 dev eth0
>
> # ip route show table 10
> 10.0.2.0/24 dev eth0 proto kernel scope link src 10.0.2.15
> local 10.0.2.15 dev eth0 proto kernel scope host src 10.0.2.15
>
> I have read dhclient's documentation, and did not find any mention of
> either VRFs or custom routing tables... Have I missed some obvious
> trick here?
>
> Mateusz
> _______________________________________________
> dhcp-users mailing list
> dhcp-users@lists.isc.org
> https://lists.isc.org/mailman/listinfo/dhcp-users
------------------------------
Message: 4
Date: Fri, 7 Jun 2019 12:48:42 +0100
From: Tony Finch <d...@dotat.at>
To: Users of ISC DHCP <dhcp-users@lists.isc.org>
Subject: Re: dhclient and custom Linux routing tables (VRF)
Message-ID: <alpine.deb.2.20.1906071238030.16...@grey.csi.cam.ac.uk>
Content-Type: text/plain; charset=US-ASCII
Mateusz Viste <mate...@viste.fr> wrote:
>
> I have read dhclient's documentation, and did not find any mention of either
> VRFs or custom routing tables... Have I missed some obvious trick here?
Network configuration changes from DHCP are handled by the
dhclient-script, which is probably supplied by your Linux distribution.
You might find you have to re-do most of the dhclient-script logic to
support VRFs, so you might be better off providing a complete replacement
script rather than using the hooks.
[ One awkward thing I have noticed is that Debian's dhclient-script always
continues after running the enter hooks, whereas the ISC versions exit
early if the enter hooks exit with a non-zero ststus, so the enter hooks
might or might not allow you to completely override parts of the
dhclient-script. ]
Tony.
--
f.anthony.n.finch <d...@dotat.at> http://dotat.at/
Whitby to Gibraltar Point: East or southeast 4 or 5, increasing 6 or 7 for a
time, veering southwest later. Slight becoming moderate. Rain for a time then
showers. Good, occasionally poor later.
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