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Today's Topics:
1. Re: key conflict message for create host by Omapi (Graham Clinch)
2. Re: key conflict message for create host by Omapi (Simon Hobson)
3. Re: key conflict message for create host by Omapi (Graham Clinch)
4. Re: key conflict message for create host by Omapi (Simon Hobson)
5. Re: key conflict message for create host by Omapi
(Shraddha Pandhe)
6. Re: key conflict message for create host by Omapi (Glenn Satchell)
7. Re: key conflict message for create host by Omapi (Simon Hobson)
8. Re: key conflict message for create host by Omapi (Glenn Satchell)
----------------------------------------------------------------------
Message: 1
Date: Wed, 21 Oct 2015 13:43:12 +0100
From: Graham Clinch <[email protected]>
To: [email protected]
Subject: Re: key conflict message for create host by Omapi
Message-ID: <[email protected]>
Content-Type: text/plain; charset=windows-1252
On 21/10/2015 08:13, Simon Hobson wrote:
> Clodoaldo de Borba Lambiase <[email protected]> wrote:
>
>> I'm trying to enable duplicate MACs in different subnets for ISC DHCP- 4.3.3
>> with OMAPI host entries. I have two IPs with the same MAC address in
>> different subnets.
>
> It sounds like you are trying to do via OMAPI the equivalent of this in the
> config file
>
> host "blah1" { hardware ethernet aa:bb:cc:dd:ff ; ip address 192.168.1.123 ; }
> host "blah2" { hardware ethernet aa:bb:cc:dd:ff ; ip address 192.168.2.123 ; }
>
> IIRC this doesn't work.
Drifting gently away from the original request, just noting that
multiple host records (in different subnets) with the same hardware
address *does* work (at least in 4.2) when configured through the
configuration files. I've not tried it via OMAPI.
=-=-=
subnet 148.88.141.0 netmask 255.255.255.0 {
option routers 148.88.141.1;
}
# static_allocation_id=18460
host 148.88.141.167 {
fixed-address 148.88.141.167;
hardware ethernet 00:13:44:00:05:0c;
}
[...]
subnet 148.88.186.0 netmask 255.255.254.0 {
option routers 148.88.186.1;
}
# static_allocation_id=24416
host 148.88.186.71 {
fixed-address 148.88.186.71;
hardware ethernet 00:13:44:00:05:0c;
}
=-=-=
>From a cursory skim of server/omapi.c, it does appear that the omapi
server tries to find any lease with the same hardware address and
doesn't restrict it to being within the same subnet.
Graham
------------------------------
Message: 2
Date: Wed, 21 Oct 2015 13:58:17 +0100
From: Simon Hobson <[email protected]>
To: Users of ISC DHCP <[email protected]>
Subject: Re: key conflict message for create host by Omapi
Message-ID: <[email protected]>
Content-Type: text/plain; charset=us-ascii
Graham Clinch <[email protected]> wrote:
> Drifting gently away from the original request, just noting that
> multiple host records (in different subnets) with the same hardware
> address *does* work (at least in 4.2) when configured through the
> configuration files. I've not tried it via OMAPI.
>
> =-=-=
> subnet 148.88.141.0 netmask 255.255.255.0 {
> option routers 148.88.141.1;
> }
>
> # static_allocation_id=18460
> host 148.88.141.167 {
> fixed-address 148.88.141.167;
> hardware ethernet 00:13:44:00:05:0c;
> }
>
> [...]
>
> subnet 148.88.186.0 netmask 255.255.254.0 {
> option routers 148.88.186.1;
> }
>
> # static_allocation_id=24416
> host 148.88.186.71 {
> fixed-address 148.88.186.71;
> hardware ethernet 00:13:44:00:05:0c;
> }
Bear in mind that you *WILL* get strange effects if you put host statements
within a subnet declaration. When the client connects to a different subnet,
it'll still match the host declarations (so is still a "known host"), but while
it'll get a dynamic IP appropriate to the subnet it is in, it'll inherit
options like "router" from (one of) the subnet(s) where the host declaration(s)
have been put.
Hence the standard advice - do *NOT* put host statements anywhere but the
global scope.
------------------------------
Message: 3
Date: Wed, 21 Oct 2015 14:35:18 +0100
From: Graham Clinch <[email protected]>
To: [email protected]
Subject: Re: key conflict message for create host by Omapi
Message-ID: <[email protected]>
Content-Type: text/plain; charset=windows-1252
On 21/10/2015 13:58, Simon Hobson wrote:
>> =-=-=
>> subnet 148.88.141.0 netmask 255.255.255.0 {
>> option routers 148.88.141.1;
>> }
>>
>> # static_allocation_id=18460
>> host 148.88.141.167 {
>> fixed-address 148.88.141.167;
>> hardware ethernet 00:13:44:00:05:0c;
>> }
>>
>> [...]
>>
>> subnet 148.88.186.0 netmask 255.255.254.0 {
>> option routers 148.88.186.1;
>> }
>>
>> # static_allocation_id=24416
>> host 148.88.186.71 {
>> fixed-address 148.88.186.71;
>> hardware ethernet 00:13:44:00:05:0c;
>> }
>
> Bear in mind that you *WILL* get strange effects if you put host statements
> within a subnet declaration. When the client connects to a different subnet,
> it'll still match the host declarations (so is still a "known host"), but
> while it'll get a dynamic IP appropriate to the subnet it is in, it'll
> inherit options like "router" from (one of) the subnet(s) where the host
> declaration(s) have been put.
>
> Hence the standard advice - do *NOT* put host statements anywhere but the
> global scope.
Hm? Am I missing something, or was that just a general warning? The
hosts are defined in the same 'global' scope as the subnets. Given the
configuration above (though 1000x longer..), we don't see hosts being
given the wrong router addresses when they visit other subnets.
Graham
------------------------------
Message: 4
Date: Wed, 21 Oct 2015 18:58:01 +0100
From: Simon Hobson <[email protected]>
To: Users of ISC DHCP <[email protected]>
Subject: Re: key conflict message for create host by Omapi
Message-ID: <[email protected]>
Content-Type: text/plain; charset=us-ascii
Graham Clinch <[email protected]> wrote:
> ? Am I missing something, or was that just a general warning?
Sorry, my mistake - I'd misread your post as having put the host declarations
inside the subnet declarations.
------------------------------
Message: 5
Date: Wed, 21 Oct 2015 11:20:36 -0700
From: Shraddha Pandhe <[email protected]>
To: Users of ISC DHCP <[email protected]>
Subject: Re: key conflict message for create host by Omapi
Message-ID:
<cagwnvr5uuc4h4++jyigjjq3bwljtq-ta-23i_7f9y7xta2q...@mail.gmail.com>
Content-Type: text/plain; charset="utf-8"
Hi Graham,
<< multiple host records (in different subnets) with the same hardware
<< address *does* work (at least in 4.2)
Just wondering, how will dhcp request/response work in this case? Based on
my understanding, host config lookup happens solely on the basis of mac
address. But if two hosts have same mac address, how will the server decide?
Am I missing something?
On Wed, Oct 21, 2015 at 10:58 AM, Simon Hobson <[email protected]>
wrote:
> Graham Clinch <[email protected]> wrote:
>
> > ? Am I missing something, or was that just a general warning?
>
> Sorry, my mistake - I'd misread your post as having put the host
> declarations inside the subnet declarations.
>
> _______________________________________________
> dhcp-users mailing list
> [email protected]
> https://lists.isc.org/mailman/listinfo/dhcp-users
>
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------------------------------
Message: 6
Date: Thu, 22 Oct 2015 14:57:35 +1100
From: "Glenn Satchell" <[email protected]>
To: "Users of ISC DHCP" <[email protected]>
Subject: Re: key conflict message for create host by Omapi
Message-ID:
<[email protected]>
Content-Type: text/plain;charset=iso-8859-1
The address has to match the subnet where the request came from. So
consider a laptop that can be connected to many subnets. If there is a
valid host statement it will use that address, otherwise it uses the
dynamic range, and classes etc.
regards,
-glenn
On Thu, October 22, 2015 5:20 am, Shraddha Pandhe wrote:
> Hi Graham,
>
> << multiple host records (in different subnets) with the same hardware
> << address *does* work (at least in 4.2)
>
>
> Just wondering, how will dhcp request/response work in this case? Based on
> my understanding, host config lookup happens solely on the basis of mac
> address. But if two hosts have same mac address, how will the server
> decide?
>
> Am I missing something?
>
>
> On Wed, Oct 21, 2015 at 10:58 AM, Simon Hobson <[email protected]>
> wrote:
>
>> Graham Clinch <[email protected]> wrote:
>>
>> > ? Am I missing something, or was that just a general warning?
>>
>> Sorry, my mistake - I'd misread your post as having put the host
>> declarations inside the subnet declarations.
>>
>> _______________________________________________
>> dhcp-users mailing list
>> [email protected]
>> https://lists.isc.org/mailman/listinfo/dhcp-users
>>
> _______________________________________________
> dhcp-users mailing list
> [email protected]
> https://lists.isc.org/mailman/listinfo/dhcp-users
------------------------------
Message: 7
Date: Thu, 22 Oct 2015 11:19:25 +0100
From: Simon Hobson <[email protected]>
To: Users of ISC DHCP <[email protected]>
Subject: Re: key conflict message for create host by Omapi
Message-ID: <[email protected]>
Content-Type: text/plain; charset=us-ascii
Glenn Satchell <[email protected]> wrote:
> The address has to match the subnet where the request came from. So
> consider a laptop that can be connected to many subnets. If there is a
> valid host statement it will use that address, otherwise it uses the
> dynamic range, and classes etc.
I was wondering about a more subtle issue, but consultation of the man page
resolved that :
> When dhcpd tries to find a host declaration for a client, it first looks for
> a host declaration which has a fixed-address declaration that lists an IP
> address that is valid for the subnet or shared network on which the client is
> booting. If it doesn't find any such entry, it tries to find an entry which
> has no fixed-address declaration.
So it would appear that if the host is in a subnet where none of the
fixed-address options match, then those host statements themselves don't match.
Thus there is no issue over which options get applied (should you apply other
options within the host declaration).
------------------------------
Message: 8
Date: Thu, 22 Oct 2015 21:24:49 +1100
From: "Glenn Satchell" <[email protected]>
To: "Users of ISC DHCP" <[email protected]>
Subject: Re: key conflict message for create host by Omapi
Message-ID:
<[email protected]>
Content-Type: text/plain;charset=iso-8859-1
On Thu, October 22, 2015 9:19 pm, Simon Hobson wrote:
> Glenn Satchell <[email protected]> wrote:
>
>> The address has to match the subnet where the request came from. So
>> consider a laptop that can be connected to many subnets. If there is a
>> valid host statement it will use that address, otherwise it uses the
>> dynamic range, and classes etc.
>
> I was wondering about a more subtle issue, but consultation of the man
> page resolved that :
>> When dhcpd tries to find a host declaration for a client, it first looks
>> for a host declaration which has a fixed-address declaration that lists
>> an IP address that is valid for the subnet or shared network on which
>> the client is booting. If it doesn't find any such entry, it tries to
>> find an entry which has no fixed-address declaration.
>
> So it would appear that if the host is in a subnet where none of the
> fixed-address options match, then those host statements themselves don't
> match. Thus there is no issue over which options get applied (should you
> apply other options within the host declaration).
The host statement *does* match, for example the host is still a "known"
host. It's a match based on "hardware ethernet". It's just that the
fixed-address does not match the subnet.
regards,
-glenn
------------------------------
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