Dual Nics on different networks?

Yes you should be able to do this. What have you done
and what problems have you encountered?

"Matthew" <(E-Mail Removed)> wrote in message news:
> i want to setup my windows 2003 server with a seperate nic
> card on a seperate network for backups. i cant seem to
> get windows to allow me to do this. shouldn't i be able
> to setup multiple nics in the server on seperate networks?

i want to setup my windows 2003 server with a seperate nic
card on a seperate network for backups. i cant seem to
get windows to allow me to do this. shouldn't i be able
to setup multiple nics in the server on seperate networks?

if i try to use a different gateway address the server can
no longer contact any other servers on it's primary
subnet. if i do not enter a dns server, then noone can
login to the domain controller/dns server anymore.



>-----Original Message-----
>Yes you should be able to do this. What have you done
>and what problems have you encountered?
>
>"Matthew" <(E-Mail Removed)> wrote in
message news:
>> i want to setup my windows 2003 server with a seperate
nic
>> card on a seperate network for backups. i cant seem to
>> get windows to allow me to do this. shouldn't i be able
>> to setup multiple nics in the server on seperate
networks?
>
>
>.
>

Only 1 default gateway should be used on your setup. Have a
look at the following:

Default Gateway Configuration for Multihomed Computers
http://support.microsoft.com/default...b;en-us;157025


"Matthew" <(E-Mail Removed)> wrote in message news:
> if i try to use a different gateway address the server can
> no longer contact any other servers on it's primary
> subnet. if i do not enter a dns server, then noone can
> login to the domain controller/dns server anymore.

Hi Mathew,

Can you give us details of your physical setup?
It would be hard to advise you without knowing
how the server is being used between the two
disjointed networks.

"Matthew" <(E-Mail Removed)> wrote in message news:
> will traffic flow thru these ports? i mean would my
> backup servers try to communicate with other servers thru
> the server with the dual nics? i don't want that.

will traffic flow thru these ports? i mean would my
backup servers try to communicate with other servers thru
the server with the dual nics? i don't want that.


>-----Original Message-----
>Only 1 default gateway should be used on your setup.
Have a
>look at the following:
>
>Default Gateway Configuration for Multihomed Computers
>http://support.microsoft.com/default.aspx?scid=kb;en-
us;157025
>
>
>"Matthew" <(E-Mail Removed)> wrote in
message news:
>> if i try to use a different gateway address the server
can
>> no longer contact any other servers on it's primary
>> subnet. if i do not enter a dns server, then noone can
>> login to the domain controller/dns server anymore.
>
>
>.
>

i have two nics in the server A.

first nic is assigned 10.10.2.45/24 with a gateway of 2.6
the DNS address is 10.10.2.45

the second nic is assigned 10.10.4.11/24 with no gateway.
the DNS address is 10.10.2.45


I have 1 nic in server B. (Backup SErver)
the nic is assigned 10.10.4.10/25 no gateway
the DNS entry is 10.10.4.11

the servers seem able to communicate but for some reason
other pc's on the network can't login and my exchange
server gets really weird ldap errors and communication
errors with the DC.

hope this helps a bit
>-----Original Message-----
>Hi Mathew,
>
>Can you give us details of your physical setup?
>It would be hard to advise you without knowing
>how the server is being used between the two
>disjointed networks.
>
>"Matthew" <(E-Mail Removed)> wrote in
message news:
>> will traffic flow thru these ports? i mean would my
>> backup servers try to communicate with other servers
thru
>> the server with the dual nics? i don't want that.
>
>
>.
>

As Michael said, multihomed servers can have problems with name
resolution (and browsing). You will need to make sure that the second NIC
(for backup) doesn't register with your WINS or DNS server, as that will
upset your LAN operations. As a general rule, try to avoid using multihomed
domain controllers.

You could look at KB 289735. This refers to Remote Access, but it will
show you the sort of problem that multihoming your server can cause and ways
around it.

Traffic on the backup subnet cannot cross to the LAN subnet unless
routing is enabled. Routing is disabled by default, so you should not need
to do anything to keep them sparated.


"Matthew" <(E-Mail Removed)> wrote in message
news:8eeb01c49691$0a6593f0$(E-Mail Removed)...
> i have two nics in the server A.
>
> first nic is assigned 10.10.2.45/24 with a gateway of 2.6
> the DNS address is 10.10.2.45
>
> the second nic is assigned 10.10.4.11/24 with no gateway.
> the DNS address is 10.10.2.45
>
>
> I have 1 nic in server B. (Backup SErver)
> the nic is assigned 10.10.4.10/25 no gateway
> the DNS entry is 10.10.4.11
>
> the servers seem able to communicate but for some reason
> other pc's on the network can't login and my exchange
> server gets really weird ldap errors and communication
> errors with the DC.
>
> hope this helps a bit
> >-----Original Message-----
> >Hi Mathew,
> >
> >Can you give us details of your physical setup?
> >It would be hard to advise you without knowing
> >how the server is being used between the two
> >disjointed networks.
> >
> >"Matthew" <(E-Mail Removed)> wrote in
> message news:
> >> will traffic flow thru these ports? i mean would my
> >> backup servers try to communicate with other servers
> thru
> >> the server with the dual nics? i don't want that.
> >
> >
> >.
> >

Ok, if you are not supposed to use multihomed domain
controllers then how would your backup server be able to
login to the domain to backup all the servers it needs
to. each server the backup server is contacting has a
secondary gbit nic to communicate with that server on that
private network. can you explain this? am i missing
something here?



>-----Original Message-----
> As Michael said, multihomed servers can have problems
with name
>resolution (and browsing). You will need to make sure
that the second NIC
>(for backup) doesn't register with your WINS or DNS
server, as that will
>upset your LAN operations. As a general rule, try to
avoid using multihomed
>domain controllers.
>
> You could look at KB 289735. This refers to Remote
Access, but it will
>show you the sort of problem that multihoming your server
can cause and ways
>around it.
>
> Traffic on the backup subnet cannot cross to the LAN
subnet unless
>routing is enabled. Routing is disabled by default, so
you should not need
>to do anything to keep them sparated.
>
>
>"Matthew" <(E-Mail Removed)> wrote in
message
>news:8eeb01c49691$0a6593f0$(E-Mail Removed)...
>> i have two nics in the server A.
>>
>> first nic is assigned 10.10.2.45/24 with a gateway of
2.6
>> the DNS address is 10.10.2.45
>>
>> the second nic is assigned 10.10.4.11/24 with no
gateway.
>> the DNS address is 10.10.2.45
>>
>>
>> I have 1 nic in server B. (Backup SErver)
>> the nic is assigned 10.10.4.10/25 no gateway
>> the DNS entry is 10.10.4.11
>>
>> the servers seem able to communicate but for some reason
>> other pc's on the network can't login and my exchange
>> server gets really weird ldap errors and communication
>> errors with the DC.
>>
>> hope this helps a bit
>> >-----Original Message-----
>> >Hi Mathew,
>> >
>> >Can you give us details of your physical setup?
>> >It would be hard to advise you without knowing
>> >how the server is being used between the two
>> >disjointed networks.
>> >
>> >"Matthew" <(E-Mail Removed)> wrote
in
>> message news:
>> >> will traffic flow thru these ports? i mean would my
>> >> backup servers try to communicate with other servers
>> thru
>> >> the server with the dual nics? i don't want that.
>> >
>> >
>> >.
>> >
>
>
>.
>

"Matthew" <(E-Mail Removed)> wrote in message
news:975201c49733$63b02130$(E-Mail Removed)...
> Ok, if you are not supposed to use multihomed domain
> controllers then how would your backup server be able to
> login to the domain to backup all the servers it needs
> to. each server the backup server is contacting has a
> secondary gbit nic to communicate with that server on that
> private network. can you explain this? am i missing
> something here?

Multi-homing any machines other than Firewall or Proxy machines is a
"kludge" to begin with, that's why the problems that exist with doing so
actually exist. The proper way to have two subnets is to put a router
between the subnets and leave one NIC in all the machines. High speed
"backbones" are also supposed to be done with Routers that are designed to
run at those speeds. The physical topology of a network should be
independent of the computers that run on it and the computers should not,
themselves, make up the topology.

I think a lot of people try to solve or avoid problems that don't exist to
begin with. I run our backup right across the normal regular LAN and don't
use an "backup network". It is a fully switched and segmented LAN and the
effect of the backup traffic doesn't even get noticed.

Also the backup traffic is "directed" it is not "broadcasted". So just using
a Switch instead of a hub will already keep the traffic "segmented" from the
rest of the LAN even if it is all one segment.

--

Phillip Windell [MCP, MVP, CCNA]
www.wandtv.com