2 Network Card hook up to same network

[cst112]

Can someone tell me what they know about connecting two network cards to the
same network.

This is my scenario. I have a Laptop that has both a wireless network card
and a normal network card. I have enable both and it seems to work fine.
The DHCP server assigns separate IP addresses to both cards and I am able to
get access to the network. How does DNS work when this happens?
I know if the network cards support teaming, you can do that but that is not
what I am trying to do. I also know when you have two different computers
with the same hostname, it causes a duplicate name on network error and it
doesn't allow the computers to connect to the domain. Also which network
card is used to access the internet when you have two cards and which IP
address gets resolved first in DNS for the host? I just want to know the
logisitics of how this works.

In the end:
I would like to enable both network cards on the laptop but I would like to
use the wire LAN when docked and the wireless when roaming.

 

[Chris]

You could create a shortcut for each connection on your desktop and
then enable or disable them as appropriate with a right click.


Chris

 

[cst112]

I know I can do that. I want someone to explain to me what happens when
both cards are active. How does windows 2000 dns handle it, how does the
workstation (windows 2000) handle it. Or is having 2 network cards on the
same network going to cause problems etc.

Kevin

 

[Ace Fekay [MVP]]

In

I know I can do that. I want someone to explain to me what happens
when both cards are active. How does windows 2000 dns handle it, how
does the workstation (windows 2000) handle it. Or is having 2
network cards on the same network going to cause problems etc.

Kevin

I guess it would depend on the binding order. Whichever is at the top of the
list, will always be used, unless there's something referencing the other
card, I don't really think it will ever get to use it. Think about it....

Besides, teaming is the way to go with mutli interfaces on the same subnet.

--
Regards,
Ace

Please direct all replies to the newsgroup so all can benefit.
This posting is provided "AS-IS" with no warranties and confers no
rights.

Ace Fekay, MCSE 2000, MCSE+I, MCSA, MCT, MVP
Microsoft Windows MVP - Active Directory

 

[cst112]

So having two network cards on the same network is "legal" and DNS and
active directory will not complain about this configuration?

Kevin


"Ace Fekay [MVP]"

 

[Kevin D. Goodknecht [MVP]]

In

So having two network cards on the same network is "legal" and DNS and
active directory will not complain about this configuration?

Are you talking about on the same subnet looking at each other?

That is a problem, if NetBIOS over TCP/IP or NetBEUI are enabled, the NIC
will only see that the is another machine on the network with its name and
will disable both. This won't happen if NetBIOS is disabled on at least one
card.

It won't help much, unless the NICs are teamed, Teamed NICs share the load
and the rest of the network only sees one IP address. Unteamed NICs don't
share the load because they have different addresses, it is just one or the
other, usually just one.

 

[Ace Fekay [MVP]]

In

In
Are you talking about on the same subnet looking at each other?

That is a problem, if NetBIOS over TCP/IP or NetBEUI are enabled, the
NIC will only see that the is another machine on the network with its
name and will disable both. This won't happen if NetBIOS is disabled
on at least one card.

It won't help much, unless the NICs are teamed, Teamed NICs share the
load and the rest of the network only sees one IP address. Unteamed
NICs don't share the load because they have different addresses, it
is just one or the other, usually just one.

Good point, since it will cause a duplicate name error, and will cause reg
errors in WINS if using WINS.

As for AD or DNS complaining, that depends. If mutlihomed with non-teamed
NICs on a DC or DNS or a DC with DNS on it, and not configured properly,
then YES, it will cause problems.

Team them. I don't see why CST112 is trying to avoid teaming them??


--
Regards,
Ace

Please direct all replies to the newsgroup so all can benefit.
This posting is provided "AS-IS" with no warranties and confers no
rights.

Ace Fekay, MCSE 2000, MCSE+I, MCSA, MCT, MVP
Microsoft Windows MVP - Active Directory

 

[cst112]

Hello Ace and Kevin,

I would think about teaming them on a server. If you recall the original
message was talking about a wireless NIC and a wired NIC (Dell Latitiude
with built in wireless and lan). Are you saying these nics would support
teaming? All I want to know is if I enable both devices, it will use either
one or the other. I tried it briefly and I didn't get any errors and it
seemed to work. (I only have TCP/IP configured). The only other option I
have is for them to manually connect to the wireless which I know will cause
some user problems.

I would strictly use wireless but I have noticed on testing that when you
log out(when computer is already on) and then login, it doesn't do the
domain login scripts because the wireless is not connected and you have to
manually connect. When I restart the laptop, it stalls at the login screen
for a while when it is connecting to the wireless but it does connect to the
wireless and does execute the login scripts. I can foresee people being
disconnected from the wireless all the time when the laptop goes into a
sleep mode. I have the connection configured to automatically connect to
the network but it doesn't seem to happen all the time.

I want to thank everyone for responding.

Kevin



"Ace Fekay [MVP]"

 

[Ace Fekay [MVP]]

HI Kevin, inline below....

In

Hello Ace and Kevin,

I would think about teaming them on a server. If you recall the
original message was talking about a wireless NIC and a wired NIC
(Dell Latitiude with built in wireless and lan). Are you saying
these nics would support teaming?

Sorry, after re-reading your original post, I see what you mean.
Teaming is highly dependent on the manuf drivers. I kind of doubt wireless
and wired NICs are teamable, but then you can check with Dell.

All I want to know is if I enable
both devices, it will use either one or the other. I tried it
briefly and I didn't get any errors and it seemed to work. (I only
have TCP/IP configured). The only other option I have is for them to
manually connect to the wireless which I know will cause some user
problems.

I see. I guess a little training for them may help?

I would strictly use wireless but I have noticed on testing that when
you log out(when computer is already on) and then login, it doesn't
do the domain login scripts because the wireless is not connected and
you have to manually connect. When I restart the laptop, it stalls
at the login screen for a while when it is connecting to the wireless
but it does connect to the wireless and does execute the login
scripts.

Maybe that's either due to the latency during the time it's connecting,
and/or not using your internal DNS? I assume you are using your internal
DNS, so it maybe the latency causing that.

I can foresee people being disconnected from the wireless
all the time when the laptop goes into a sleep mode. I have the
connection configured to automatically connect to the network but it
doesn't seem to happen all the time.

I can understand that. I've seen the same thing with wireless. Wireless is
nice, unabound technology, but there are quirks with the hardware.

I want to thank everyone for responding.

Kevin

As I mentioned, the binding order of the interfaces will actually dictate
which one is going to be used first. Having both NICs enabled may cause
problems in the long run, such as dupe names, etc, but one of them will be
used before the other. I guess at this point need to test it out, or train
the users to disable one or the other or create mutliple Hardware profiles
with the wireless NIC enabled on one, and not the other and vice-versa for
the wired NIC.


--
Regards,
Ace

Please direct all replies to the newsgroup so all can benefit.
This posting is provided "AS-IS" with no warranties and confers no
rights.

Ace Fekay, MCSE 2000, MCSE+I, MCSA, MCT, MVP
Microsoft Windows MVP - Active Directory