Discussion:
DHCP server -- "Reservation(active)" (repost)
(too old to reply)
david
2009-07-16 07:52:53 UTC
Permalink
Looking for a DHCP explanation....

(1) What does "Reservation(active)" mean when shown on an Address Lease?
(2) What does "Reservation(inactive)" mean? (1 client)
(3) How does a client without a reservation get to be listed as "infinite",
when the scope specifies 2 days?
(4) Can an infinite lease be broken?


Context:

Using SBS 2003 server, with a separate network for the VOIP phones.

The old network diagram claims the VOIP phones have a separate DHCP server,
and are on a separate switch/ BSD router.

But MOST of the phones are showing up as Address Leases in the SBS DHCP
management console snap-in,
But none of the phones are showing up in the DHCP log (enable DHCP audit
logging)

But most of those are shown as "Reservation(active)" under lease expiration.

One phone with a reservation is shown as "Reservation(inactive)"
Two phones without reservations are shown as "infinite"

At least one phone is not shown on this list, which seems to indicate that
this is not the DHCP server used for that network, but if that's the case,
why are the others 'active'?

I don't want to just delete all this stuff if 'active' means that the
information is somehow leaking through between the two networks.

(david)
Lanwench [MVP - Exchange]
2009-07-16 13:22:43 UTC
Permalink
Post by david
Looking for a DHCP explanation....
(1) What does "Reservation(active)" mean when shown on an Address Lease?
That someone created a DHCP reservation for an IP address based on a MAC
address, and that node is "live" and using the reservation.
Post by david
(2) What does "Reservation(inactive)" mean? (1 client)
That someone created a DHCP reservation for an IP address based on a MAC
address, and that node is not live (is not connected or using it).
Post by david
(3) How does a client without a reservation get to be listed as
"infinite", when the scope specifies 2 days?
'
No idea. How and where are you seeing this?
Post by david
(4) Can an infinite lease be broken?
What do you mean by broken?
Post by david
Using SBS 2003 server, with a separate network for the VOIP phones.
The old network diagram claims the VOIP phones have a separate DHCP
server, and are on a separate switch/ BSD router.
OK, and have you found that device/server? What IP range is it using? Would
be smart to have it use something other than the IP network used by the data
LAN.
Post by david
But MOST of the phones are showing up as Address Leases in the SBS
DHCP management console snap-in,
As active?
Post by david
But none of the phones are showing up in the DHCP log (enable DHCP
audit logging)
But most of those are shown as "Reservation(active)" under lease expiration.
Most of *which* ... ?
Post by david
One phone with a reservation is shown as "Reservation(inactive)"
Then it isn't actually there.
Post by david
Two phones without reservations are shown as "infinite"
Not sure what that means.
Post by david
At least one phone is not shown on this list, which seems to indicate
that this is not the DHCP server used for that network, but if that's
the case, why are the others 'active'?
I don't want to just delete all this stuff if 'active' means that the
information is somehow leaking through between the two networks.
(david)
What is the physical network topology here? Trace it out and test it. Are
you using a switch with VLANs or an entirely separate switch for the phones?
What did the phone vendor tell you is handling DHCP for the phones? Who is
responsible for the phones? I'd bring them in and have a talk. If the VOIP
phones are truly separate then they can't be showing up *anywhere* on the
SBS DHCP console at all.

You can test this by disabling DHCP on the SBS box (turn off the service)
and try to connect one of your phones.
david
2009-07-17 01:15:18 UTC
Permalink
"Lanwench [MVP - Exchange]"
Post by Lanwench [MVP - Exchange]
Post by david
Looking for a DHCP explanation....
(1) What does "Reservation(active)" mean when shown on an Address Lease?
That someone created a DHCP reservation for an IP address based on a MAC
address, and that node is "live" and using the reservation.
Post by david
(2) What does "Reservation(inactive)" mean? (1 client)
That someone created a DHCP reservation for an IP address based on a MAC
address, and that node is not live (is not connected or using it).
Post by david
(3) How does a client without a reservation get to be listed as
"infinite", when the scope specifies 2 days?
'
No idea. How and where are you seeing this?
Post by david
(4) Can an infinite lease be broken?
What do you mean by broken?
Post by david
Using SBS 2003 server, with a separate network for the VOIP phones.
The old network diagram claims the VOIP phones have a separate DHCP
server, and are on a separate switch/ BSD router.
OK, and have you found that device/server? What IP range is it using?
Would be smart to have it use something other than the IP network used by
the data LAN.
Post by david
But MOST of the phones are showing up as Address Leases in the SBS
DHCP management console snap-in,
As active?
Post by david
But none of the phones are showing up in the DHCP log (enable DHCP
audit logging)
But most of those are shown as "Reservation(active)" under lease expiration.
Most of *which* ... ?
Post by david
One phone with a reservation is shown as "Reservation(inactive)"
Then it isn't actually there.
Post by david
Two phones without reservations are shown as "infinite"
Not sure what that means.
Post by david
At least one phone is not shown on this list, which seems to indicate
that this is not the DHCP server used for that network, but if that's
the case, why are the others 'active'?
I don't want to just delete all this stuff if 'active' means that the
information is somehow leaking through between the two networks.
(david)
What is the physical network topology here? Trace it out and test it. Are
you using a switch with VLANs or an entirely separate switch for the
phones? What did the phone vendor tell you is handling DHCP for the
phones? Who is responsible for the phones? I'd bring them in and have a
talk. If the VOIP phones are truly separate then they can't be showing up
*anywhere* on the SBS DHCP console at all.
You can test this by disabling DHCP on the SBS box (turn off the service)
and try to connect one of your phones.
That's a good idea: I can do that after hours without breaking anything.

The phones are on a separate subnet on a separate switch. I would believe
that it was all completely separate if not for these "active" reservations.
Everything is in 10.x.x.x, but all subnetted 255.255.255.0

It should be, and is, possible for these phones to phone across into the
SBS local subnet, to talk with a 'soft' phone on a workstation on the
local subnet. Either the phone directory service is on both subnets, or
there is routing between the subnets. Would routing between the subnets
be sufficient to make the reservations "active"?
"infinite" is the length of the lease shown for two phones without
reservations.


(david)
Lanwench [MVP - Exchange]
2009-07-17 02:06:55 UTC
Permalink
Post by david
"Lanwench [MVP - Exchange]"
Post by Lanwench [MVP - Exchange]
Post by david
Looking for a DHCP explanation....
(1) What does "Reservation(active)" mean when shown on an Address Lease?
That someone created a DHCP reservation for an IP address based on a
MAC address, and that node is "live" and using the reservation.
Post by david
(2) What does "Reservation(inactive)" mean? (1 client)
That someone created a DHCP reservation for an IP address based on a
MAC address, and that node is not live (is not connected or using
it).
Post by david
(3) How does a client without a reservation get to be listed as
"infinite", when the scope specifies 2 days?
'
No idea. How and where are you seeing this?
Post by david
(4) Can an infinite lease be broken?
What do you mean by broken?
Post by david
Using SBS 2003 server, with a separate network for the VOIP phones.
The old network diagram claims the VOIP phones have a separate DHCP
server, and are on a separate switch/ BSD router.
OK, and have you found that device/server? What IP range is it using?
Would be smart to have it use something other than the IP network
used by the data LAN.
Post by david
But MOST of the phones are showing up as Address Leases in the SBS
DHCP management console snap-in,
As active?
Post by david
But none of the phones are showing up in the DHCP log (enable DHCP
audit logging)
But most of those are shown as "Reservation(active)" under lease expiration.
Most of *which* ... ?
Post by david
One phone with a reservation is shown as "Reservation(inactive)"
Then it isn't actually there.
Post by david
Two phones without reservations are shown as "infinite"
Not sure what that means.
Post by david
At least one phone is not shown on this list, which seems to
indicate that this is not the DHCP server used for that network,
but if that's the case, why are the others 'active'?
I don't want to just delete all this stuff if 'active' means that
the information is somehow leaking through between the two networks.
(david)
What is the physical network topology here? Trace it out and test
it. Are you using a switch with VLANs or an entirely separate switch
for the phones? What did the phone vendor tell you is handling DHCP
for the phones? Who is responsible for the phones? I'd bring them in
and have a talk. If the VOIP phones are truly separate then they
can't be showing up *anywhere* on the SBS DHCP console at all.
You can test this by disabling DHCP on the SBS box (turn off the
service) and try to connect one of your phones.
That's a good idea: I can do that after hours without breaking
anything.
The phones are on a separate subnet on a separate switch. I would
believe that it was all completely separate if not for these "active"
reservations. Everything is in 10.x.x.x, but all subnetted
255.255.255.0
Change it. Put your data on 10.1.1.0/24 and your phones on 10.1.2.0/24.
Post by david
It should be, and is, possible for these phones to phone across into
the SBS local subnet, to talk with a 'soft' phone on a workstation on
the local subnet.
But is that desirable?
Post by david
Either the phone directory service is on both
subnets, or there is routing between the subnets. Would routing
between the subnets be sufficient to make the reservations "active"?
If you had iphelper, yes.
Post by david
"infinite" is the length of the lease shown for two phones without
reservations.
Honestly not sure. Sounds very odd to me.
Post by david
(david)
Miles Li [MSFT]
2009-07-17 08:20:52 UTC
Permalink
Hello,

Thank you for posting here. Also thanks for Lanwench's great input.

According to your description, I understand that:

Your VOIP phones that are in a different subnet get the IP address leased
by the DHCP service in local subnet.

If I have misunderstood the problem, please don't hesitate to let me know.

By default, a router separates the broadcast domain while DHCP negotiation
is based on the broadcast. In the other word, your VOIP phones DHCP
requests will never arrive the local subnet unless when you have the DHCP
relay enabled on the router.

If you have any questions or concerns, please do not hesitate to let me
know.




Best regards,

Miles Li

Microsoft Online Newsgroup Support

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david
2009-07-20 03:14:29 UTC
Permalink
Post by Miles Li [MSFT]
If you have any questions or concerns, please do not hesitate to let
me know.
1) What does "Reservation(active)" mean when shown on an Address Lease?
(2) What does "Reservation(inactive)" mean? (1 client)
(3) How does a client without a reservation get to be listed as "infinite",
when the scope specifies 2 days?

(david)
Miles Li [MSFT]
2009-07-20 10:10:57 UTC
Permalink
Hello David,

Thanks for the update.

1. A Reservation lease becomes active when the device with specified MAC
address gets the IP lease.

2. A Reservation lease becomes inactive when it expires or is not used by a
client. A Reservation with a wrong MAC address specified will always be
inactive.

3. From the description that you have 2 days specified for the scope, a
client without a Reservation still has a lease as "infinite". From my
experience, this entry may be the bad one that results from the failure
when attempt to retrieve the lease duration value. The "infinite" works out
to something around 50,000 days. If you cannot wait for the lease time to
expire, you may manually delete this entry and renew the lease on the
client to check how it works.

If you have any questions or concerns, please do not hesitate to let me
know.


Best regards,

Miles Li

Microsoft Online Newsgroup Support

==================================================================
Please post your SBS 2008 related questions to the SBS newsgroup on Connect
website:
https://connect.microsoft.com/sbs08/community/discussion/richui/default.aspx


Please post your EBS related questions to the EBS newsgroup on Connect
website:
https://connect.microsoft.com/ebs08/community/discussion/richui/default.aspx


If you want to use a newsreader other than a web forum to access these
newsgroups,
please refer to the following blog to apply NNTP password and configure a
newsreader:
http://msmvps.com/blogs/bradley/archive/2008/11/02/signing-up-for-the-sbs-20
08-newsgroups.aspx
==================================================================
When responding to posts, please "Reply to Group" via your newsreader so
that others may learn and benefit from your issue.
==================================================================
This posting is provided "AS IS" with no warranties, and confers no rights.
==================================================================
Les Connor [SBS MVP]
2009-07-27 21:49:30 UTC
Permalink
And - if a reservation is created, and the mac address is on the reserved
IP, the reservation will show "inactive" until the device renews it's IP. At
which time it becomes "active" ;-).
--
-----------------------------------------------
Les Connor [SBS MVP]

"Lanwench [MVP - Exchange]"
Post by Lanwench [MVP - Exchange]
Post by david
Looking for a DHCP explanation....
(1) What does "Reservation(active)" mean when shown on an Address Lease?
That someone created a DHCP reservation for an IP address based on a MAC
address, and that node is "live" and using the reservation.
Post by david
(2) What does "Reservation(inactive)" mean? (1 client)
That someone created a DHCP reservation for an IP address based on a MAC
address, and that node is not live (is not connected or using it).
Post by david
(3) How does a client without a reservation get to be listed as
"infinite", when the scope specifies 2 days?
'
No idea. How and where are you seeing this?
Post by david
(4) Can an infinite lease be broken?
What do you mean by broken?
Post by david
Using SBS 2003 server, with a separate network for the VOIP phones.
The old network diagram claims the VOIP phones have a separate DHCP
server, and are on a separate switch/ BSD router.
OK, and have you found that device/server? What IP range is it using?
Would be smart to have it use something other than the IP network used by
the data LAN.
Post by david
But MOST of the phones are showing up as Address Leases in the SBS
DHCP management console snap-in,
As active?
Post by david
But none of the phones are showing up in the DHCP log (enable DHCP
audit logging)
But most of those are shown as "Reservation(active)" under lease expiration.
Most of *which* ... ?
Post by david
One phone with a reservation is shown as "Reservation(inactive)"
Then it isn't actually there.
Post by david
Two phones without reservations are shown as "infinite"
Not sure what that means.
Post by david
At least one phone is not shown on this list, which seems to indicate
that this is not the DHCP server used for that network, but if that's
the case, why are the others 'active'?
I don't want to just delete all this stuff if 'active' means that the
information is somehow leaking through between the two networks.
(david)
What is the physical network topology here? Trace it out and test it. Are
you using a switch with VLANs or an entirely separate switch for the
phones? What did the phone vendor tell you is handling DHCP for the
phones? Who is responsible for the phones? I'd bring them in and have a
talk. If the VOIP phones are truly separate then they can't be showing up
*anywhere* on the SBS DHCP console at all.
You can test this by disabling DHCP on the SBS box (turn off the service)
and try to connect one of your phones.
david
2009-07-28 02:24:30 UTC
Permalink
Thanks. That perhaps makes sense: If these things were some how
getting "infinite" leases, then they would remain active forever.

(david)
Post by Les Connor [SBS MVP]
And - if a reservation is created, and the mac address is on the reserved
IP, the reservation will show "inactive" until the device renews it's IP.
At which time it becomes "active" ;-).
--
-----------------------------------------------
Les Connor [SBS MVP]
"Lanwench [MVP - Exchange]"
Post by Lanwench [MVP - Exchange]
Post by david
Looking for a DHCP explanation....
(1) What does "Reservation(active)" mean when shown on an Address Lease?
That someone created a DHCP reservation for an IP address based on a MAC
address, and that node is "live" and using the reservation.
Post by david
(2) What does "Reservation(inactive)" mean? (1 client)
That someone created a DHCP reservation for an IP address based on a MAC
address, and that node is not live (is not connected or using it).
Post by david
(3) How does a client without a reservation get to be listed as
"infinite", when the scope specifies 2 days?
'
No idea. How and where are you seeing this?
Post by david
(4) Can an infinite lease be broken?
What do you mean by broken?
Post by david
Using SBS 2003 server, with a separate network for the VOIP phones.
The old network diagram claims the VOIP phones have a separate DHCP
server, and are on a separate switch/ BSD router.
OK, and have you found that device/server? What IP range is it using?
Would be smart to have it use something other than the IP network used by
the data LAN.
Post by david
But MOST of the phones are showing up as Address Leases in the SBS
DHCP management console snap-in,
As active?
Post by david
But none of the phones are showing up in the DHCP log (enable DHCP
audit logging)
But most of those are shown as "Reservation(active)" under lease expiration.
Most of *which* ... ?
Post by david
One phone with a reservation is shown as "Reservation(inactive)"
Then it isn't actually there.
Post by david
Two phones without reservations are shown as "infinite"
Not sure what that means.
Post by david
At least one phone is not shown on this list, which seems to indicate
that this is not the DHCP server used for that network, but if that's
the case, why are the others 'active'?
I don't want to just delete all this stuff if 'active' means that the
information is somehow leaking through between the two networks.
(david)
What is the physical network topology here? Trace it out and test it. Are
you using a switch with VLANs or an entirely separate switch for the
phones? What did the phone vendor tell you is handling DHCP for the
phones? Who is responsible for the phones? I'd bring them in and have a
talk. If the VOIP phones are truly separate then they can't be showing
up *anywhere* on the SBS DHCP console at all.
You can test this by disabling DHCP on the SBS box (turn off the service)
and try to connect one of your phones.
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