DHCP Handing out IPs on Wrong Network

[Guest Kbalz]

We have one DHCP Server, which is also our Primary Domain Controller.

This is also our Primary DNS Server. It is running Windows 2003 x64 R2

SP2.

 

Our reserved range of IPs run from 192.168.1.1 - x.x.x.80. DHCP is

configured to hand out ranges from x.x.x.81 - x.x.x.200.

 

All of our clients are running Windows XP Pro, SP2 (some are on SP1

still, but very few). We have about 100 client machines.

 

Laptops are very prone (I'd say, 80% of the time) to this: The laptop

will leave our network (salesman takes a business trip) for a week or

two, when he or she returns, the laptop is assigned a 192.168.2.1xx IP

address. We have a 192.168.2.xxx network, but it is physically on the

other side of our ISA Server. This only seems to happen when the

laptop uses a wireless connection. This is a basic wireless reciever,

nothing fancy.. We have workstations that connect to the network

through the receiver, and they always get on the x.x.1.xxx network.

We've only noticed this activity since this summer.

 

Our ISA 2006 Server Standard has four NICs. 192.168.1.xxx,

192.168.2.xxx, 192.168.3.xxx, 192.168.10.xxx. (we call them the 1-

network, 2-network.. etc). The 2 network is actually our DMZ, and

another firewall surrounds that before the internet modems.

 

Basically, I'm wondering WHY DHCP is handing out IPs on the 2-network,

to laptops that leave the building for a few days, and only when they

connect through our wireless router. Or how can I investigate this?

 

Thanks, Kb

[Guest James McIllece [MS]]

Re: DHCP Handing out IPs on Wrong Network

 

Hi Kurtas --

 

When DHCP responds to a client request for a lease, it chooses which

configured scope to use for the lease/IP based on the IP address of the

first router (the DHCP client's default gateway IP address) that forwarded

the DHCP Discover message from the client. To do this, the router must have

DHCP forwarding enabled.

 

I don't fully understand your network setup, but somehow the DHCP traffic

is being forwarded through a router with an IP address that is from the

same scope that DHCP uses to issue the IP lease to the client.

 

Kbalz <Kurtas.Balczak@gmail.com> wrote in news:16a9e469-a093-4b08-949b-

06a2718f2192@p69g2000hsa.googlegroups.com:

> We have one DHCP Server, which is also our Primary Domain Controller.

> This is also our Primary DNS Server. It is running Windows 2003 x64 R2

> SP2.

>

> Our reserved range of IPs run from 192.168.1.1 - x.x.x.80. DHCP is

> configured to hand out ranges from x.x.x.81 - x.x.x.200.

>

> All of our clients are running Windows XP Pro, SP2 (some are on SP1

> still, but very few). We have about 100 client machines.

>

> Laptops are very prone (I'd say, 80% of the time) to this: The laptop

> will leave our network (salesman takes a business trip) for a week or

> two, when he or she returns, the laptop is assigned a 192.168.2.1xx IP

> address. We have a 192.168.2.xxx network, but it is physically on the

> other side of our ISA Server. This only seems to happen when the

> laptop uses a wireless connection. This is a basic wireless reciever,

> nothing fancy.. We have workstations that connect to the network

> through the receiver, and they always get on the x.x.1.xxx network.

> We've only noticed this activity since this summer.

>

> Our ISA 2006 Server Standard has four NICs. 192.168.1.xxx,

> 192.168.2.xxx, 192.168.3.xxx, 192.168.10.xxx. (we call them the 1-

> network, 2-network.. etc). The 2 network is actually our DMZ, and

> another firewall surrounds that before the internet modems.

>

> Basically, I'm wondering WHY DHCP is handing out IPs on the 2-network,

> to laptops that leave the building for a few days, and only when they

> connect through our wireless router. Or how can I investigate this?

>

> Thanks, Kb

>

 

 

 

--

James McIllece, Microsoft

 

Please do not send email directly to this alias. This is my online account

name for newsgroup participation only.

 

This posting is provided "AS IS" with no warranties, and confers no rights.

[Guest Kbalz]

Re: DHCP Handing out IPs on Wrong Network

 

On Dec 17, 1:36 pm, "James McIllece [MS]"

<james...@online.microsoft.com> wrote:

> Hi Kurtas --

>

> When DHCP responds to a client request for a lease, it chooses which

> configured scope to use for the lease/IP based on the IP address of the

> first router (the DHCP client's default gateway IP address) that forwarded

> the DHCP Discover message from the client. To do this, the router must have

> DHCP forwarding enabled.

>

> I don't fully understand your network setup, but somehow the DHCP traffic

> is being forwarded through a router with an IP address that is from the

> same scope that DHCP uses to issue the IP lease to the client.

>

> Kbalz <Kurtas.Balc...@gmail.com> wrote in news:16a9e469-a093-4b08-949b-

> 06a2718f2...@p69g2000hsa.googlegroups.com:

>

>

>

>

>

> > We have one DHCP Server, which is also our Primary Domain Controller.

> > This is also our Primary DNS Server. It is running Windows 2003 x64 R2

> > SP2.

>

> > Our reserved range of IPs run from 192.168.1.1 - x.x.x.80. DHCP is

> > configured to hand out ranges from x.x.x.81 - x.x.x.200.

>

> > All of our clients are running Windows XP Pro, SP2 (some are on SP1

> > still, but very few). We have about 100 client machines.

>

> > Laptops are very prone (I'd say, 80% of the time) to this: The laptop

> > will leave our network (salesman takes a business trip) for a week or

> > two, when he or she returns, the laptop is assigned a 192.168.2.1xx IP

> > address. We have a 192.168.2.xxx network, but it is physically on the

> > other side of our ISA Server. This only seems to happen when the

> > laptop uses a wireless connection. This is a basic wireless reciever,

> > nothing fancy.. We have workstations that connect to the network

> > through the receiver, and they always get on the x.x.1.xxx network.

> > We've only noticed this activity since this summer.

>

> > Our ISA 2006 Server Standard has four NICs. 192.168.1.xxx,

> > 192.168.2.xxx, 192.168.3.xxx, 192.168.10.xxx. (we call them the 1-

> > network, 2-network.. etc). The 2 network is actually our DMZ, and

> > another firewall surrounds that before the internet modems.

>

> > Basically, I'm wondering WHY DHCP is handing out IPs on the 2-network,

> > to laptops that leave the building for a few days, and only when they

> > connect through our wireless router. Or how can I investigate this?

>

> > Thanks, Kb

>

> --

> James McIllece, Microsoft

>

> Please do not send email directly to this alias. This is my online account

> name for newsgroup participation only.

>

> This posting is provided "AS IS" with no warranties, and confers no rights.- Hide quoted text -

>

> - Show quoted text -

 

Mm - I can not seem to connect to the wireless switch.. perhaps it

jumped on the 2-Network and that is why clients are receiving such.

I'll investigate more and respond with what I find.

[Guest Kbalz]

Re: DHCP Handing out IPs on Wrong Network

 

On Dec 17, 1:46 pm, Kbalz <Kurtas.Balc...@gmail.com> wrote:

> On Dec 17, 1:36 pm, "James McIllece [MS]"

>

>

>

>

>

> <james...@online.microsoft.com> wrote:

> > Hi Kurtas --

>

> > When DHCP responds to a client request for a lease, it chooses which

> > configured scope to use for the lease/IP based on the IP address of the

> > first router (the DHCP client's default gateway IP address) that forwarded

> > the DHCP Discover message from the client. To do this, the router must have

> > DHCP forwarding enabled.

>

> > I don't fully understand your network setup, but somehow the DHCP traffic

> > is being forwarded through a router with an IP address that is from the

> > same scope that DHCP uses to issue the IP lease to the client.

>

> > Kbalz <Kurtas.Balc...@gmail.com> wrote in news:16a9e469-a093-4b08-949b-

> > 06a2718f2...@p69g2000hsa.googlegroups.com:

>

> > > We have one DHCP Server, which is also our Primary Domain Controller.

> > > This is also our Primary DNS Server. It is running Windows 2003 x64 R2

> > > SP2.

>

> > > Our reserved range of IPs run from 192.168.1.1 - x.x.x.80. DHCP is

> > > configured to hand out ranges from x.x.x.81 - x.x.x.200.

>

> > > All of our clients are running Windows XP Pro, SP2 (some are on SP1

> > > still, but very few). We have about 100 client machines.

>

> > > Laptops are very prone (I'd say, 80% of the time) to this: The laptop

> > > will leave our network (salesman takes a business trip) for a week or

> > > two, when he or she returns, the laptop is assigned a 192.168.2.1xx IP

> > > address. We have a 192.168.2.xxx network, but it is physically on the

> > > other side of our ISA Server. This only seems to happen when the

> > > laptop uses a wireless connection. This is a basic wireless reciever,

> > > nothing fancy.. We have workstations that connect to the network

> > > through the receiver, and they always get on the x.x.1.xxx network.

> > > We've only noticed this activity since this summer.

>

> > > Our ISA 2006 Server Standard has four NICs. 192.168.1.xxx,

> > > 192.168.2.xxx, 192.168.3.xxx, 192.168.10.xxx. (we call them the 1-

> > > network, 2-network.. etc). The 2 network is actually our DMZ, and

> > > another firewall surrounds that before the internet modems.

>

> > > Basically, I'm wondering WHY DHCP is handing out IPs on the 2-network,

> > > to laptops that leave the building for a few days, and only when they

> > > connect through our wireless router. Or how can I investigate this?

>

> > > Thanks, Kb

>

> > --

> > James McIllece, Microsoft

>

> > Please do not send email directly to this alias. This is my online account

> > name for newsgroup participation only.

>

> > This posting is provided "AS IS" with no warranties, and confers no rights.- Hide quoted text -

>

> > - Show quoted text -

>

> Mm - I can not seem to connect to the wireless switch.. perhaps it

> jumped on the 2-Network and that is why clients are receiving such.

> I'll investigate more and respond with what I find.- Hide quoted text -

>

> - Show quoted text -

 

I've connected to the wireless device (it was ignoring IE7 requests,

probably need new firmware or something) with Firefox. The device is

just a Wireless Access Point, it plugs directly into the main switch

along with the rest of the wire'd workstations. DHCP on the WAP is

disabled. The ISA Server and DHCP server also plug into the switch.

The ISA Server is the default gateway for the client machines (and the

WAP), 192.168.1.1. Within ISA, traffic filters through the rules and

spits out of 192.168.2.1, then traffic travels to the next firewall.

 

Does that give enough information to figure out why clients are

requesting IPs for the 2-network.

[Guest Kbalz]

Re: DHCP Handing out IPs on Wrong Network

 

On Dec 17, 1:59 pm, Kbalz <Kurtas.Balc...@gmail.com> wrote:

> On Dec 17, 1:46 pm, Kbalz <Kurtas.Balc...@gmail.com> wrote:

>

>

>

>

>

> > On Dec 17, 1:36 pm, "James McIllece [MS]"

>

> > <james...@online.microsoft.com> wrote:

> > > Hi Kurtas --

>

> > > When DHCP responds to a client request for a lease, it chooses which

> > > configured scope to use for the lease/IP based on the IP address of the

> > > first router (the DHCP client's default gateway IP address) that forwarded

> > > the DHCP Discover message from the client. To do this, the router must have

> > > DHCP forwarding enabled.

>

> > > I don't fully understand your network setup, but somehow the DHCP traffic

> > > is being forwarded through a router with an IP address that is from the

> > > same scope that DHCP uses to issue the IP lease to the client.

>

> > > Kbalz <Kurtas.Balc...@gmail.com> wrote in news:16a9e469-a093-4b08-949b-

> > > 06a2718f2...@p69g2000hsa.googlegroups.com:

>

> > > > We have one DHCP Server, which is also our Primary Domain Controller..

> > > > This is also our Primary DNS Server. It is running Windows 2003 x64 R2

> > > > SP2.

>

> > > > Our reserved range of IPs run from 192.168.1.1 - x.x.x.80.  DHCP is

> > > > configured to hand out ranges from x.x.x.81 - x.x.x.200.

>

> > > > All of our clients are running Windows XP Pro, SP2 (some are on SP1

> > > > still, but very few). We have about 100 client machines.

>

> > > > Laptops are very prone (I'd say, 80% of the time) to this:  The laptop

> > > > will leave our network (salesman takes a business trip) for a week or

> > > > two, when he or she returns, the laptop is assigned a 192.168.2.1xx IP

> > > > address.  We have a 192.168.2.xxx network, but it is physically on the

> > > > other side of our ISA Server. This only seems to happen when the

> > > > laptop uses a wireless connection. This is a basic wireless reciever,

> > > > nothing fancy.. We have workstations that connect to the network

> > > > through the receiver, and they always get on the x.x.1.xxx network.

> > > > We've only noticed this activity since this summer.

>

> > > > Our ISA 2006 Server Standard has four NICs. 192.168.1.xxx,

> > > > 192.168.2.xxx, 192.168.3.xxx, 192.168.10.xxx. (we call them the 1-

> > > > network, 2-network.. etc). The 2 network is actually our DMZ, and

> > > > another firewall surrounds that before the internet modems.

>

> > > > Basically, I'm wondering WHY DHCP is handing out IPs on the 2-network,

> > > > to laptops that leave the building for a few days, and only when they

> > > > connect through our wireless router. Or how can I investigate this?

>

> > > > Thanks, Kb

>

> > > --

> > > James McIllece, Microsoft

>

> > > Please do not send email directly to this alias.  This is my online account

> > > name for newsgroup participation only.

>

> > > This posting is provided "AS IS" with no warranties, and confers no rights.- Hide quoted text -

>

> > > - Show quoted text -

>

> > Mm - I can not seem to connect to the wireless switch.. perhaps it

> > jumped on the 2-Network and that is why clients are receiving such.

> > I'll investigate more and respond with what I find.- Hide quoted text -

>

> > - Show quoted text -

>

> I've connected to the wireless device (it was ignoring IE7 requests,

> probably need new firmware or something) with Firefox.  The device is

> just a Wireless Access Point, it plugs directly into the main switch

> along with the rest of the wire'd workstations. DHCP on the WAP is

> disabled. The ISA Server and DHCP server also plug into the switch.

> The ISA Server is the default gateway for the client machines (and the

> WAP), 192.168.1.1.  Within ISA, traffic filters through the rules and

> spits out of 192.168.2.1, then traffic travels to the next firewall.

>

> Does that give enough information to figure out why clients are

> requesting IPs for the 2-network.- Hide quoted text -

>

> - Show quoted text -

 

Can anyone provide other possible things to look into? Its very

bothersome.

 

To solve the problem on the laptops.. I run ipconfig /release

ipconfig /dnsflush ipconfig /renew That solves it everytime.

[Guest Kbalz]

Re: DHCP Handing out IPs on Wrong Network

 

On Dec 28 2007, 7:44 am, Kbalz <Kurtas.Balc...@gmail.com> wrote:

> On Dec 17, 1:59 pm,Kbalz<Kurtas.Balc...@gmail.com> wrote:

>

>

>

>

>

> > On Dec 17, 1:46 pm,Kbalz<Kurtas.Balc...@gmail.com> wrote:

>

> > > On Dec 17, 1:36 pm, "James McIllece [MS]"

>

> > > <james...@online.microsoft.com> wrote:

> > > > Hi Kurtas --

>

> > > > When DHCP responds to a client request for a lease, it chooses which

> > > > configured scope to use for the lease/IP based on the IP address of the

> > > > first router (the DHCP client's default gateway IP address) that forwarded

> > > > the DHCP Discover message from the client. To do this, the router must have

> > > > DHCP forwarding enabled.

>

> > > > I don't fully understand your network setup, but somehow the DHCP traffic

> > > > is being forwarded through a router with an IP address that is from the

> > > > same scope that DHCP uses to issue the IP lease to the client.

>

> > > >Kbalz<Kurtas.Balc...@gmail.com> wrote in news:16a9e469-a093-4b08-949b-

> > > > 06a2718f2...@p69g2000hsa.googlegroups.com:

>

> > > > > We have one DHCP Server, which is also our Primary Domain Controller.

> > > > > This is also our Primary DNS Server. It is running Windows 2003 x64 R2

> > > > > SP2.

>

> > > > > Our reserved range of IPs run from 192.168.1.1 - x.x.x.80.  DHCP is

> > > > > configured to hand out ranges from x.x.x.81 - x.x.x.200.

>

> > > > > All of our clients are running Windows XP Pro, SP2 (some are on SP1

> > > > > still, but very few). We have about 100 client machines.

>

> > > > > Laptops are very prone (I'd say, 80% of the time) to this:  The laptop

> > > > > will leave our network (salesman takes a business trip) for a week or

> > > > > two, when he or she returns, the laptop is assigned a 192.168.2.1xx IP

> > > > > address.  We have a 192.168.2.xxx network, but it is physically on the

> > > > > other side of our ISA Server. This only seems to happen when the

> > > > > laptop uses a wireless connection. This is a basic wireless reciever,

> > > > > nothing fancy.. We have workstations that connect to the network

> > > > > through the receiver, and they always get on the x.x.1.xxx network..

> > > > > We've only noticed this activity since this summer.

>

> > > > > Our ISA 2006 Server Standard has four NICs. 192.168.1.xxx,

> > > > > 192.168.2.xxx, 192.168.3.xxx, 192.168.10.xxx. (we call them the 1-

> > > > > network, 2-network.. etc). The 2 network is actually our DMZ, and

> > > > > another firewall surrounds that before the internet modems.

>

> > > > > Basically, I'm wondering WHY DHCP is handing out IPs on the 2-network,

> > > > > to laptops that leave the building for a few days, and only when they

> > > > > connect through our wireless router. Or how can I investigate this?

>

> > > > > Thanks, Kb

>

> > > > --

> > > > James McIllece, Microsoft

>

> > > > Please do not send email directly to this alias.  This is my online account

> > > > name for newsgroup participation only.

>

> > > > This posting is provided "AS IS" with no warranties, and confers no rights.- Hide quoted text -

>

> > > > - Show quoted text -

>

> > > Mm - I can not seem to connect to the wireless switch.. perhaps it

> > > jumped on the 2-Network and that is why clients are receiving such.

> > > I'll investigate more and respond with what I find.- Hide quoted text -

>

> > > - Show quoted text -

>

> > I've connected to the wireless device (it was ignoring IE7 requests,

> > probably need new firmware or something) with Firefox.  The device is

> > just a Wireless Access Point, it plugs directly into the main switch

> > along with the rest of the wire'd workstations. DHCP on the WAP is

> > disabled. The ISA Server and DHCP server also plug into the switch.

> > The ISA Server is the default gateway for the client machines (and the

> > WAP), 192.168.1.1.  Within ISA, traffic filters through the rules and

> > spits out of 192.168.2.1, then traffic travels to the next firewall.

>

> > Does that give enough information to figure out why clients are

> > requesting IPs for the 2-network.- Hide quoted text -

>

> > - Show quoted text -

>

> Can anyone provide other possible things to look into? Its very

> bothersome.

>

> To solve the problem on the laptops.. I run ipconfig /release

> ipconfig /dnsflush   ipconfig /renew     That solves it everytime.- Hide quoted text -

>

> - Show quoted text -

 

Still could use a hand on this one. DHCP is not working for laptops!!

[Guest Kbalz]

Re: DHCP Handing out IPs on Wrong Network

 

On Jan 8, 10:02 am, Kbalz <Kurtas.Balc...@gmail.com> wrote:

> On Dec 28 2007, 7:44 am, Kbalz <Kurtas.Balc...@gmail.com> wrote:

>

>

>

>

>

> > On Dec 17, 1:59 pm,Kbalz<Kurtas.Balc...@gmail.com> wrote:

>

> > > On Dec 17, 1:46 pm,Kbalz<Kurtas.Balc...@gmail.com> wrote:

>

> > > > On Dec 17, 1:36 pm, "James McIllece [MS]"

>

> > > > <james...@online.microsoft.com> wrote:

> > > > > Hi Kurtas --

>

> > > > > When DHCP responds to a client request for a lease, it chooses which

> > > > > configured scope to use for the lease/IP based on the IP address of the

> > > > > first router (the DHCP client's default gateway IP address) that forwarded

> > > > > the DHCP Discover message from the client. To do this, the router must have

> > > > > DHCP forwarding enabled.

>

> > > > > I don't fully understand your network setup, but somehow the DHCP traffic

> > > > > is being forwarded through a router with an IP address that is from the

> > > > > same scope that DHCP uses to issue the IP lease to the client.

>

> > > > >Kbalz<Kurtas.Balc...@gmail.com> wrote in news:16a9e469-a093-4b08-949b-

> > > > > 06a2718f2...@p69g2000hsa.googlegroups.com:

>

> > > > > > We have one DHCP Server, which is also our Primary Domain Controller.

> > > > > > This is also our Primary DNS Server. It is running Windows 2003 x64 R2

> > > > > > SP2.

>

> > > > > > Our reserved range of IPs run from 192.168.1.1 - x.x.x.80.  DHCP is

> > > > > > configured to hand out ranges from x.x.x.81 - x.x.x.200.

>

> > > > > > All of our clients are running Windows XP Pro, SP2 (some are on SP1

> > > > > > still, but very few). We have about 100 client machines.

>

> > > > > > Laptops are very prone (I'd say, 80% of the time) to this:  The laptop

> > > > > > will leave our network (salesman takes a business trip) for a week or

> > > > > > two, when he or she returns, the laptop is assigned a 192.168.2.1xx IP

> > > > > > address.  We have a 192.168.2.xxx network, but it is physically on the

> > > > > > other side of our ISA Server. This only seems to happen when the

> > > > > > laptop uses a wireless connection. This is a basic wireless reciever,

> > > > > > nothing fancy.. We have workstations that connect to the network

> > > > > > through the receiver, and they always get on the x.x.1.xxx network.

> > > > > > We've only noticed this activity since this summer.

>

> > > > > > Our ISA 2006 Server Standard has four NICs. 192.168.1.xxx,

> > > > > > 192.168.2.xxx, 192.168.3.xxx, 192.168.10.xxx. (we call them the 1-

> > > > > > network, 2-network.. etc). The 2 network is actually our DMZ, and

> > > > > > another firewall surrounds that before the internet modems.

>

> > > > > > Basically, I'm wondering WHY DHCP is handing out IPs on the 2-network,

> > > > > > to laptops that leave the building for a few days, and only when they

> > > > > > connect through our wireless router. Or how can I investigate this?

>

> > > > > > Thanks, Kb

>

> > > > > --

> > > > > James McIllece, Microsoft

>

> > > > > Please do not send email directly to this alias.  This is my online account

> > > > > name for newsgroup participation only.

>

> > > > > This posting is provided "AS IS" with no warranties, and confers no rights.- Hide quoted text -

>

> > > > > - Show quoted text -

>

> > > > Mm - I can not seem to connect to the wireless switch.. perhaps it

> > > > jumped on the 2-Network and that is why clients are receiving such.

> > > > I'll investigate more and respond with what I find.- Hide quoted text -

>

> > > > - Show quoted text -

>

> > > I've connected to the wireless device (it was ignoring IE7 requests,

> > > probably need new firmware or something) with Firefox.  The device is

> > > just a Wireless Access Point, it plugs directly into the main switch

> > > along with the rest of the wire'd workstations. DHCP on the WAP is

> > > disabled. The ISA Server and DHCP server also plug into the switch.

> > > The ISA Server is the default gateway for the client machines (and the

> > > WAP), 192.168.1.1.  Within ISA, traffic filters through the rules and

> > > spits out of 192.168.2.1, then traffic travels to the next firewall.

>

> > > Does that give enough information to figure out why clients are

> > > requesting IPs for the 2-network.- Hide quoted text -

>

> > > - Show quoted text -

>

> > Can anyone provide other possible things to look into? Its very

> > bothersome.

>

> > To solve the problem on the laptops.. I run ipconfig /release

> > ipconfig /dnsflush   ipconfig /renew     That solves it everytime.- Hide quoted text -

>

> > - Show quoted text -

>

> Still could use a hand on this one. DHCP is not working for laptops!!- Hide quoted text -

>

> - Show quoted text -

 

I got an iPAQ on our network this week, today it received a xxx.2.xx

IP..