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Today's Topics:
1. agent.remote-id matching (Andre Mamitzsch)
2. Re: Recommendation for redundancy (Tiago SR)
----------------------------------------------------------------------
Message: 1
Date: Tue, 6 Mar 2018 22:32:36 +0100
From: Andre Mamitzsch <an...@mamitzsch.de>
To: Users of ISC DHCP <dhcp-users@lists.isc.org>
Subject: agent.remote-id matching
Message-ID: <32fb3d8e-5a47-4129-a545-d0124d394...@mamitzsch.de>
Content-Type: text/plain; charset="utf-8"
Hi
We are experiencing a problem with matching the agent.remote-id in a DOCSIS
environment. The CMTS inserts the CM MAC in the agent.remote-id, this id is
then used in subclasses on the server. I was debugging an issue where the class
matching did not work - when inspecting the lease file, I found that the
agent.remote-id is stored as string ("DNm+SP?) and not as a MAC address as
expected.
I analyzed the MAC address and all values are in the range between 0 and 127:
44 -> 68 -> D
4e -> 78 -> N
6d -> 109 -> m
2b -> 43 -> +
53 -> 83 -> S
50 -> 80 -> P
As a proof, I added a new subclass entry using the string and got a match when
I restarted the device.
MAC addresses seem to be converted to their ascii representation if they
contain only printable ascii values. I suspect that it has something to do the
the ?isascii? and ?isdigit? checks in common/options.c, beginning in line 1828.
I have tested agains 4.3.4 and 4.3.6P1 - both show the same behavior. I believe
that we had a similar issue with "hardware ethernet <MAC>?, but this was years
ago and I? m not sure. I was searching the bug reports and the mailing list
but were not able to find anything similar - so any hints or advises are
welcome !
Thanks
Andre
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Message: 2
Date: Tue, 06 Mar 2018 19:34:51 -0300
From: Tiago SR <lis...@tiagosr.com>
To: "Users of ISC DHCP" <dhcp-users@lists.isc.org>
Subject: Re: Recommendation for redundancy
Message-ID:
<161fd73f75a.d62707bc74234.7028210951061623...@tiagosr.com>
Content-Type: text/plain; charset="UTF-8"
My suggestion may also work if you have a centralized leases database, which
both servers query (directly or via Radius) to assign addresses.
---- On Tue, 06 Mar 2018 16:08:25 -0300 Simon Hobson <dh...@thehobsons.co.uk>
wrote ----
> Tiago SR <lis...@tiagosr.com> wrote:
>
> > If you make use of DHCP Relay or can implement it, you could get the
> > servers failover by VRRP, IP SLA, OSPF, etc.
> > The DHCP Relay would query a DHCP Server IP address that would
> > automatically point to secondary server in case of primary going down.
>
> The problem with that is that unless you use the failover protocol then you
> cannot easily have a seamless handover - this is NOT a stateless server like
> a web server serving static pages. The standby server must AT ALL TIMES have
> a completer and up to date copy of what the master server has - that is not
> easy to do without using failover. If the backup server does not have a
> complete and accurate copy of the primary server's lease database then you
> will suffer from one or more potentially serious problems.
>
> Once you use failover to manage syncing the leases to the backup, then you
> might as well just use failover to manage availability.
>
> _______________________________________________
> dhcp-users mailing list
> dhcp-users@lists.isc.org
> https://lists.isc.org/mailman/listinfo/dhcp-users
>
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