IP aliases on a DHCP'ed interface

Hi

maybe this is a FAQ but I cannot ind a clear answer (apart from "it's not
possible"): is there a way to add another IP (an alias) to the same network
interface if the NIC is configured to get its address from a DHCP server?
Graphically, now way
Via netsh, if I +add* an address it replaces the DHCP configuration. Any
other more obscure way?

Thanks in advance

 

If you want to setup one static IP and another is dynamic IP, yes, you can.
This how to may help.
ipconfig
How to ping on the entire subnet. How to setup multiple IPs on NIC ...
windows server with just one NIC and have multiple public IPs for different
websites. ...
www.howtonetworking.com/Networking/ipconfig.htm


--
Bob Lin, MS-MVP, MCSE & CNE
Networking, Internet, Routing, VPN Troubleshooting on
http://www.ChicagoTech.net
How to Setup Windows, Network, VPN & Remote Access on
http://www.HowToNetworking.com

 

Sorry but from the FAQ you linked

"Q: I have a windows server with just one NIC and have multiple public IPs
for different websites. Can I have multiple IPs on one NIC?

A: Yes, the Properties of the NIC>Properties of TCP/IP>Advanced, add
additional IPs."

but as I said if the interface is configured as DHCP, then the additional
IPs section is greyed out. I need a WinXP/Vista/7 client in a DHCP
environment to have 2 IPs on the same NIC, one dynamic and one static. With
your solution is still not possible.

 

Please read one below How to setup multiple IPs on NIC: How to setup two
IPs on a computer

--
Bob Lin, MS-MVP, MCSE & CNE
Networking, Internet, Routing, VPN Troubleshooting on
http://www.ChicagoTech.net
How to Setup Windows, Network, VPN & Remote Access on
http://www.HowToNetworking.com

 

But the "Alternate Configuration" is used only if DHCP fails, while I need
two IPs at the *same time*.

 

Then you have to stop using DHCP on that machine. It is that simple.

DHCP is nothing but a "convenience tool" for dealing with mass workstations
operating in a normal way in a normal situation.

 

I have to agree with Paul. DHCP configured clients do NOT support what you
are trying to do. The machine needs to set to a static config in order to
use multiple IPs that work together.

--
Ace

This posting is provided "AS-IS" with no warranties or guarantees and
confers no rights.

Ace Fekay, MCSE 2003 & 2000, MCSA 2003 & 2000, MCSA Messaging, MCT
Microsoft Certified Trainer


For urgent issues, you may want to contact Microsoft PSS directly. Please
check http://support.microsoft.com for regional support phone numbers.

 

Err.. sorry Phillip!!! My apologies!!!

Ace

 

So going back to my first post Well at least now I'm sure there's no
other way.

Definitely, but through DHCP you can push far more network settings than
just the plain IP, so just disabling it for a number of machines is not
convenient at all. But on the other hand I *need* this second aliased IP due
to an integration with an external system that I cannot touch :/

Thanks anyway.

 

Unfortunately, it's the way it works. I agree DHCP provides numerous (scope
or server) options compared to a statically configured client, and some of
them can be statically set, but it depends on the options.

Are you using any specific scope options that you need set on all machines
that is required, which is holding you back from statically configuring a
client to intergrate wtih that external system?

Also, curious, what or how exactly do you mean this client must "integrate"
with this external system? IS it running some sort of app that needs
specific connectivity? Is there a separate router on a different IP subnet
on your local subnet that it needs to connect? (This of course will require
more thought in the design with multiple gateways on the cilent.). By
external, do you mean it is outside your subnet (internet or in a different
location), or is not part of your domain but is internal on your subnet?
What kind of system is it? If we knew some specifics about what you are
trying to accomplish, system type, protocols, client apps, etc, there is a
possibility we *may* (no guarantees of course), come up with an alternate
solution.

Ace

 

No problem,...I'll answer to most things if it isn't too bad

I actually have another guy "in real life" that calls me that all the time
too for some reason.

--
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.
-----------------------------------------------------

 

There is no such thing as an "aliased IP". A machine either has multiple
IP#s or it does not..

I'll just bet that you don't really "need" it for this external
system,...I'll bet that the whole project just simply has not been
approached properly from the beginning and that is where you real problem is
at. That is probably what we should be looking at.

--
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.
-----------------------------------------------------

 

Someone else actually calls you Paul? That is a coincidence!

I glanced at your name and after typing a few minutes and not double
checking, I could have sworn I saw Paul Bergson's name. After I hit send,
and looked again, is when I saw I messed up!!!

Ace

 

I agree with the others that I doubt this is the requirement, but just for
fun:
- do a dhcp request to obtain a spare IP and other settings
- read the obtained values into a script
- write a netsh to set the networking properties,
Anthony
http://www.airdesk.co.uk

 

Yep, there's a separate router on the same LAN but in a different subnet,
and apparently we cannot touch the router at all (not even a static route).

To clarify:

MyLAN: 10.0.0.0/20
MyGW: 10.0.0.1

TheirLAN 10.1.1.0/24
TheirGW: 10.1.1.1

so, different subnets. Actually TheirGW is attached to the same switches as
MyGW (and all the rest of MyLAN) is. I can put a static route on MyGW to
direct all traffic to TheirLAN through theirGW but as I told, I cannot even
add a static route on TheirGW to drive the traffic back, because they have
their default GW set in TheirGW so traffic to MyLAN would go through that
other GW.
So, there's this ugly hack of assigning a second IP to MyLAN machines to
become part of TheirLAN as well (as they are all in the same physical LAN)
but at the same time I don't want to loose DHCP

 

Linux jargon, sorry (although to be correct NIC is being aliased in this
case, not the IP)

 

Then it sounds like you have no choice but to use a static config.

Ace

 

Your subnet is too big. You should be using /24.
That is another "unrelated" debate for later.

There is your Core Design flaw!

It should *not* be plugged into the same switch.

Think this through. Every LAN router has two subnets (minimum),...if it
didn't it could not even exist. That means they have two subnets,...the one
on your side of their Router and one on their side of their Router.
Therefore you have to add an interface to your LAN Router that matches the
subnet of their Router. If that means your router ends up with three
interfaces,...then that is axactly what it means. This subnet (10.1.1.0/24)
will exist *only* between the two routers and should *not* be on the same
"logical wire" that the 10.0.0.0/20

[their LAN main subnet]
|
|
<their router>
|
|
[their second subnet]
|
|
<your router>-------(your router going elsewhere)
|
|
[your LAN]

The proverbial "they" in the discussion need to do their jobs,..that is what
their bosses pay them to do. If something on their LAN needs to communicate
with something your LAN,...and if that requires a static route on their
router,...then that is their job whether they like it or not and they have
to do it whether they like it or not.

People have tried that kind of stuff with me on occasion,...they didn't get
very far,...I'll do my job (and I'll do it the right way),...but they have
to do theirs,...and I haven't hesitated to put their back to the wall to get
them to do it when that is what needed to be done.

--
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.
-----------------------------------------------------

 

I don't mind being mistaken for him at all,...he just may not want it to be
the other way around,...so don't call him Phil

--
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.
-----------------------------------------------------

 

Ya'know ,...if this "they" would just configure the interface on their
router that faces your LAN with a proper IP# for your LAN there would never
have been a problem and this whole thread wounld't even exist.

That's what I would still be fighting them over. It is silly for you to
have to go through all this non-sense just because of their bull-headed
lazyness. Sorry, I just have a hard time letting these things
drop,...computers I can deal with,...humans,..sometimes I just want to slap
'em across the head.

--
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.
-----------------------------------------------------