Routing between two servers

[Joe Bucar via WinServerKB.com]

Hello,
In the same room I have two server each with 2 NIC cards. One NIC for the
internal address and one for the WAN address these servers have separate
domains and different ISP's. ServerA is my server and is Windows 2003 and
ServerB is one of my client's server and is Windows 2000. What I would
like to do is plug both internal addresses into a common switch and
establish an internal route for SQL. This will give me backup in case the
internet goes down. I currently can go out over the internet and get to
the other server but I would like to do it internally. ServerA has an
Internal address of 192.168.16.2 and ServerB internal address is
192.168.26.2. I have done a "ROUTE ADD" on both servers with each other
address but I am unable to ping or do any other access. Both servers have
ISA but I assume that the ROUTE ADD took care of that problem.
Thank You,
Joe

 

[Robert L [MS-MVP]]

assuming you have correct routing table, ISA may block the LAN traffic. For more and other information, go to http://howtonetworking.com.

Don't send e-mail or reply to me except you need consulting services. Posting on MS newsgroup will benefit all readers and you may get more help.

Bob Lin, MS-MVP, MCSE & CNE
How to Setup Windows, Network, Remote Access on http://www.HowToNetworking.com
Networking, Internet, Routing, VPN Troubleshooting on http://www.ChicagoTech.net
This posting is provided "AS IS" with no warranties.
I recommend Brinkster for web hosting!

Hello,
In the same room I have two server each with 2 NIC cards. One NIC for the
internal address and one for the WAN address these servers have separate
domains and different ISP's. ServerA is my server and is Windows 2003 and
ServerB is one of my client's server and is Windows 2000. What I would
like to do is plug both internal addresses into a common switch and
establish an internal route for SQL. This will give me backup in case the
internet goes down. I currently can go out over the internet and get to
the other server but I would like to do it internally. ServerA has an
Internal address of 192.168.16.2 and ServerB internal address is
192.168.26.2. I have done a "ROUTE ADD" on both servers with each other
address but I am unable to ping or do any other access. Both servers have
ISA but I assume that the ROUTE ADD took care of that problem.
Thank You,
Joe

 

[Herb Martin]

Hello,
In the same room I have two server each with 2 NIC cards. One NIC for the
internal address and one for the WAN address these servers have separate
domains and different ISP's. ServerA is my server and is Windows 2003 and
ServerB is one of my client's server and is Windows 2000. What I would
like to do is plug both internal addresses into a common switch and
establish an internal route for SQL.

In general, you cannot establish a "route" for a specific
service or application protocol.

Routing is done at the IP level, so it is basically an
all or nothing on most any router.

This will give me backup in case the
internet goes down. I currently can go out over the internet and get to
the other server but I would like to do it internally. ServerA has an
Internal address of 192.168.16.2 and ServerB internal address is
192.168.26.2. I have done a "ROUTE ADD" on both servers with each other
address but I am unable to ping or do any other access. Both servers have
ISA but I assume that the ROUTE ADD took care of that problem.

Manual routing on Windows servers is not at all
dynamic (lost routes will not be automatically
compensated for) with one exception: if the ADJACENT
router is down, that router will be skipped since it
doesn't answer. What this means is if your ISP's router
goes down then you might switch over, but if the router
is still visible but their net is down somewhere after,
then it will happily send to their "router" assuming that
it will work (as always.)

If you want more complicated link detection you need
more complicated dynamic routing and probably more
sophisticated routers (e.g., Cisco etc.)

A Windows server is going to go through the routing
table picking the BEST route (longest mask, lowest
metric cost, first interface in that order) and if that
router "answers" (arps etc) happily send to it no
matter what else happens outside of it's knowledge.

It will never load balance.

You might get the dynamic capability you need without
a purpose built router if you were to switch to a dynamic
protocol (RIP or OSPF) but that would imply the ISP
was willing to support exchanging such info with you.

 

[Joe Bucar via WinServerKB.com]

Thank You for your response. I think maybe I did not express myself
correctly. What I want to do is connect these servers up internally and
not go out over the internet. I have two servers in a room, ServerA
(192.168.16.2) is our in-house server and the other server ServerB
(192.168.26.2) is a customer server. The customer server has no
workstations attached to it. In this room we also have a switch that has
our workstations and our server on it. What I would like to do is take the
CAT-5 cable from the customer server's LAN port and plug it into the switch
and then access the customer server from either our server or our
workstations. I thought I could do a "ROUTE ADD 192.168.26.2 MASK
255.255.255.255 192.168.16.2 -P" and then see the customer server. Also I
thought I could do "ROUTE ADD 192.168.16.2 MASK 255.255.255.255
192.168.16.26 -P" and then see our server on the customer server. The
commands worked fine I think because when I do a ROUTE PRINT the persistent
routes show up. I can not ping ServerA from ServerB or ping ServerB from
ServerA. Once again thank you in advance.
Joe

 

[Joe Bucar via WinServerKB.com]

Sorry it is "ROUTE ADD 192.168.16.2 MASK 255.255.255.255 192.168.26.254 -P"
and "ROUTE ADD 192.168.26.2 MASK 255.255.255.255 192.168.16.254 -P".

 

[Herb Martin]

Thank You for your response. I think maybe I did not express myself
correctly. What I want to do is connect these servers up internally and
not go out over the internet. I have two servers in a room, ServerA
(192.168.16.2) is our in-house server and the other server ServerB
(192.168.26.2) is a customer server. The customer server has no
workstations attached to it. In this room we also have a switch that has
our workstations and our server on it. What I would like to do is take the
CAT-5 cable from the customer server's LAN port and plug it into the switch
and then access the customer server from either our server or our
workstations.

Ok, and if this is not the same subnet you will USUALLY
need a router between them. (Static routes can obviate this,
but then you will either have to configure each machine, use
one of them as a router, and it may be inefficient and will
use the shared bandwidth depending on the switch.
(E.g., broacasts will propagate to each network from the other.)

I thought I could do a "ROUTE ADD 192.168.26.2 MASK
255.255.255.255 192.168.16.2 -P" and then see the customer server.

Also I
thought I could do "ROUTE ADD 192.168.16.2 MASK 255.255.255.255
192.168.16.26 -P" and then see our server on the customer server.

192.168.26.254 -P"

This goes on 192.168.26.254
(it specifies itself as gateway to "dump" it on the wire", i.e., DIRECT)

This goes on 192.168.16.254
(it specifies itself as gateway to "dump" it on the wire", i.e., DIRECT)

You need each to specify the OTHER as destination on each router,
with itself as gateway. (I thought it was picky about -p going first,
but if that is working these days they probably fixed it or I
misremembered.)

commands worked fine I think because when I do a ROUTE PRINT the persistent
routes show up. I can not ping ServerA from ServerB or ping ServerB from
ServerA. Once again thank you in advance.

When the users go home, plug it into the same HUB and make
sure the switch is not interfering.

What type of switching? Layer-2 is should be no issue, but
a Router-Switch (Layer 3), although unlikely that you have
that, would have to "help" with the routing. (They would
both specify THAT router.

This would probably be the case if you had a VLAN switch.