DHCP multinet / superscope question

Hi everyone,

If I work in an office where two floors of PC's are connected via a
single switch and are using a windows 2003 DC with DHCP/DNS.

How can I allocate a class A range of IP addresses for the 1st floor
and a class B range of IP addresses for the second floor with a single
DHCP server and a single switch.

Thanks in advance!

Hi!
You can do this via "ipconfig /setclassid" on clients and Vendor/User Class
on your DHCP server. Or you can solve this problem with a layer 3 switch,
which has the routing capabilities and DCHP relay option. And finaly, you
can use a software router. In case of Microsoft solutions, it is the RRAS
server. Of course you can use a unix-like router. For example,
www.freesco.org.

Best regards,
Iuri

> Hi everyone,
>
> If I work in an office where two floors of PC's are connected via a
> single switch and are using a windows 2003 DC with DHCP/DNS.
>
> How can I allocate a class A range of IP addresses for the 1st floor
> and a class B range of IP addresses for the second floor with a single
> DHCP server and a single switch.
>
> Thanks in advance!

On Dec 7, 10:07 pm, "Iuri Cuznetov" <i...@hotbox.ru> wrote:
> Hi!
> You can do this via "ipconfig /setclassid" on clients and Vendor/User Class
> on your DHCP server. Or you can solve this problem with a layer 3 switch,
> which has the routing capabilities and DCHP relay option. And finaly, you
> can use a software router. In case of Microsoft solutions, it is the RRAS
> server. Of course you can use a unix-like router. For example,www.freesco.org.
>

Thanks for the tips! We only have 1 switch to service 2 floors. Would
it be best to setup seperate VLAN's one for each floor and do the
layer 3 routing in the procurve switch? Would the DHCP server then
require an additional NIC?

Thanks.

No extra NIC needed. But only if your switch has a DHCP relay feature.

> Thanks for the tips! We only have 1 switch to service 2 floors. Would
> it be best to setup seperate VLAN's one for each floor and do the
> layer 3 routing in the procurve switch? Would the DHCP server then
> require an additional NIC?
>
> Thanks.
>

I wanted to add a few things I never saw mentioned.

1. Class are meaningless (for the most part). They were relevant in the
1980's and early 1990's,....not anymore. The are one RFC Private Address
range for each Class,...it doesn't matter which you use,...but just use a
/24 bit mask with them (255.255.255.0)

2. Due to Ethernet efficientcy limitations, Subnets should not be allowed to
get larger than 250-300 Hosts because Broadcasts will climb too high. This
means a 24bit Mask and nothing less than that (255.255.255.0). You can make
the subnets smaller (/24+) but not bigger (-/24). So if there are less
than 254 Hosts per floor then you want a /24 bit subnet on each floor. If
there are more hosts than that then use two /24 subnets on each floor giving
you 508 Hosts per Floor. Your Layer3 Switch with VLANs can do 4 subnets
just as easy as it can do two. There would be very little cable changes if
any,...so there is really no additional work or cost involved between one
subnet per floor vs two subnets per floor.

3. Do not fall prey to the temptation of using Superscopes on the DHCP
Server. Use separate distinct independent Scopes for each subnet.
SuperScopes are for Multi-Netting,...you are not Multi-Netting here.

4. Enable DHCP Relaying (DHCP Helper Addresess) on the Router (Layer3
Switch) as I believe that has been mentioned.

--
Phillip Windell
www.wandtv.com

The views expressed, are my own and not those of my employer, or Microsoft,
or anyone else associated with me, including my cats.
-----------------------------------------------------


<(E-Mail Removed)> wrote in message
news:eea249e1-c3f5-408f-b42f-(E-Mail Removed)...
> Hi everyone,
>
> If I work in an office where two floors of PC's are connected via a
> single switch and are using a windows 2003 DC with DHCP/DNS.
>
> How can I allocate a class A range of IP addresses for the 1st floor
> and a class B range of IP addresses for the second floor with a single
> DHCP server and a single switch.
>
> Thanks in advance!

Hi Phillip,

Im very interested in this process too. So, how do I specify which IP subnet
is issued to a DHCP request by using the IP address of the router which
forwarded the request? Is it a scope option? i.e. A router at 192.168.241.3
on its LAN side forwards a request to the DHCP server and any client from
that router needs to be in 192.168.241.0.

If you have a link to a good article about this specific topic, I'd love to
read it. Thanks!
"Phillip Windell" wrote:

> I wanted to add a few things I never saw mentioned.
>
> 1. Class are meaningless (for the most part). They were relevant in the
> 1980's and early 1990's,....not anymore. The are one RFC Private Address
> range for each Class,...it doesn't matter which you use,...but just use a
> /24 bit mask with them (255.255.255.0)
>
> 2. Due to Ethernet efficientcy limitations, Subnets should not be allowed to
> get larger than 250-300 Hosts because Broadcasts will climb too high. This
> means a 24bit Mask and nothing less than that (255.255.255.0). You can make
> the subnets smaller (/24+) but not bigger (-/24). So if there are less
> than 254 Hosts per floor then you want a /24 bit subnet on each floor. If
> there are more hosts than that then use two /24 subnets on each floor giving
> you 508 Hosts per Floor. Your Layer3 Switch with VLANs can do 4 subnets
> just as easy as it can do two. There would be very little cable changes if
> any,...so there is really no additional work or cost involved between one
> subnet per floor vs two subnets per floor.
>
> 3. Do not fall prey to the temptation of using Superscopes on the DHCP
> Server. Use separate distinct independent Scopes for each subnet.
> SuperScopes are for Multi-Netting,...you are not Multi-Netting here.
>
> 4. Enable DHCP Relaying (DHCP Helper Addresess) on the Router (Layer3
> Switch) as I believe that has been mentioned.
>
> --
> Phillip Windell
> www.wandtv.com
>
> The views expressed, are my own and not those of my employer, or Microsoft,
> or anyone else associated with me, including my cats.
> -----------------------------------------------------
>
>
> <(E-Mail Removed)> wrote in message
> news:eea249e1-c3f5-408f-b42f-(E-Mail Removed)...
> > Hi everyone,
> >
> > If I work in an office where two floors of PC's are connected via a
> > single switch and are using a windows 2003 DC with DHCP/DNS.
> >
> > How can I allocate a class A range of IP addresses for the 1st floor
> > and a class B range of IP addresses for the second floor with a single
> > DHCP server and a single switch.
> >
> > Thanks in advance!
>
>
>

"SeriousSam" <(E-Mail Removed)> wrote in message
news:4EEEC557-1518-43D5-9EE4-(E-Mail Removed)...
> Im very interested in this process too. So, how do I specify which IP
> subnet
> is issued to a DHCP request by using the IP address of the router which
> forwarded the request? Is it a scope option? i.e. A router at
> 192.168.241.3
> on its LAN side forwards a request to the DHCP server and any client from
> that router needs to be in 192.168.241.0.

You don't have to do anything. The DHCP Server knows what Scope to get the
address from based on information that the Router includes in the DHCP Relay
Packets. It is actually the LAN Router that does the work,...the DHCP only
needs to have a valid Scope to serve the particular subnet in question.

Sorry, I don't have any articles on it.

--
Phillip Windell
www.wandtv.com

The views expressed, are my own and not those of my employer, or Microsoft,
or anyone else associated with me, including my cats.
-----------------------------------------------------
Understanding the ISA 2004 Access Rule Processing
http://www.isaserver.org/articles/IS...cessRules.html

Troubleshooting Client Authentication on Access Rules in ISA Server 2004
http://download.microsoft.com/downlo...7/ts_rules.doc

Microsoft Internet Security & Acceleration Server: Partners
http://www.microsoft.com/isaserver/partners/default.asp

Microsoft ISA Server Partners: Partner Hardware Solutions
http://www.microsoft.com/forefront/e...epartners.mspx
-----------------------------------------------------

On Dec 8, 9:05 am, "Phillip Windell" <philwind...@hotmail.com> wrote:
> "SeriousSam" <Serious...@discussions.microsoft.com> wrote in message

>
> You don't have to do anything. The DHCP Server knows what Scope to get the
> address from based on information that the Router includes in the DHCP Relay
> Packets. It is actually the LAN Router that does the work,...the DHCP only
> needs to have a valid Scope to serve the particular subnet in question.
>

Thanks for the info. Would the following config work for the design I
require:

1st floor 172.16.1.x subnet (VLAN 1, default_vlan)
DC with DHCP resides on this subnet. IP addr of DC / DHCP Server is
172.16.1.10
DC is in port 2 of switch (untagged)
Ports 3-24 are on default_vlan and only assigned to default_vlans
(no untagged 3-24)

2nd floor 192.168.1.x subnet (VLAN 10, new staff area)
Is the new subnet for new staff
As Port 2 on the switch is the DC I assign to both vlans (untagged
vlan1 and then tagged for vlan10)
Ports 25-48 are on this vlan only (no untagged 25-48)
ip helper-address on this vlan points to DC 172.16.1.10 on
default_vlan

Outcome:
vlan 1 has IP address of 172.16.1.x therefore clients in this VLAN
will receive 172.16.1.x scope
vlan 10 has IP address of 192.168.1.10 / ip helper-address 172.16.1.10
therefore clients in this vlan will recieve 192.168.1.x scope

Let me know if I've messed things up!!!

Procurve 2650 switch config:

ip routing
snmp-server community "public" Unrestricted
vlan 1
name "DEFAULT_VLAN"
untagged 2
ip address 172.16.1.10 255.255.255.0
no untagged 3-24

exit
vlan 10
name "2nd floor"
ip helper-address 172.16.1.10
ip address 192.168.0.1 255.255.255.0
tagged 2
no untagged 25-48
exit

<(E-Mail Removed)> wrote:
>
> Let me know if I've messed things up!!!
>
> Procurve 2650 switch config:

In fact, every network equipment producer has its own point of view on VLAN
configuration. I.e. in Allied Telesyn switches, there are no truncs between
VLANs, it has the default VLAN as service VLAN instead. So it will be
better, if you'll contact your HP support in this situation.

Haha! Thanks Phillip, that was just way too easy. I was spending time reading
articles and digging through the scope options trying to figure out how to do
that, when it was automatic all along. Incidentally if it helps anyone else
on this thread I did find some good reading here:
http://www.microsoft.com/technet/pro....mspx?mfr=true

SS



"Phillip Windell" wrote:

> "SeriousSam" <(E-Mail Removed)> wrote in message
> news:4EEEC557-1518-43D5-9EE4-(E-Mail Removed)...
> > Im very interested in this process too. So, how do I specify which IP
> > subnet
> > is issued to a DHCP request by using the IP address of the router which
> > forwarded the request? Is it a scope option? i.e. A router at
> > 192.168.241.3
> > on its LAN side forwards a request to the DHCP server and any client from
> > that router needs to be in 192.168.241.0.
>
> You don't have to do anything. The DHCP Server knows what Scope to get the
> address from based on information that the Router includes in the DHCP Relay
> Packets. It is actually the LAN Router that does the work,...the DHCP only
> needs to have a valid Scope to serve the particular subnet in question.
>
> Sorry, I don't have any articles on it.
>
> --
> Phillip Windell
> www.wandtv.com
>
> The views expressed, are my own and not those of my employer, or Microsoft,
> or anyone else associated with me, including my cats.
> -----------------------------------------------------
> Understanding the ISA 2004 Access Rule Processing
> http://www.isaserver.org/articles/IS...cessRules.html
>
> Troubleshooting Client Authentication on Access Rules in ISA Server 2004
> http://download.microsoft.com/downlo...7/ts_rules.doc
>
> Microsoft Internet Security & Acceleration Server: Partners
> http://www.microsoft.com/isaserver/partners/default.asp
>
> Microsoft ISA Server Partners: Partner Hardware Solutions
> http://www.microsoft.com/forefront/e...epartners.mspx
> -----------------------------------------------------
>
>
>