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Zero0ne
Asked: 2010-03-23 15:15:13 +0800 CST

Crossover cable in addition to normal network connection on servers?

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I have 2 servers, both with Windows 2003 R2 Each have 2 NIC ports that are 10/100/1000 They are both connected to our LAN + joined to the domain (1 NIC port free on each server)

The problem is that our main router is only 10/100 on the ports that these servers are connected to.

Since one server is going to host SQL 2005 and the other will be running Altiris NS7, I was hoping that I could use a crossover cable to connect the two directly, thus taking advantage of their 1gbps NIC cards.

Is this possible? If so what steps do I need to take to accomplish this? What needs to be done to make sure that when the app server is communicating with the SQL server that it is using the direct link vs traversing the LAN?

Thanks a lot!

sql-server-2005 windows-server-2003 networking

3 Answers

  1. Best Answer

    I'm not sure about the exact network cards that you have, but I have done this with 10/100/1000 nics and it works just like it does on 10/100 nics. You may want to take measures such as manually setting the speed and duplex to 1000/full (gigabit must always use full duplex) to avoid issues with autonegotiation.

    You could put the ip and host name of the other server in each server's host file. That would ensure that they use the crossover private nic. You may want to use both the short name and any fully-qualified names in there. I.e., 10.0.0.1 server1 server1.acme.com server1.hq.acme.com. Windows always checks the host file before DNS when resolving names for ip sockets resolution.

    You should maintain the default gateway on the other nics. Windows can only use one default gateway anyway.

    DNS - do not specify that the crossover nics register in DNS. This will definitely cause problems.

    Probably a good idea to have the crossover nics on a subnet separate from the other nics. And of course not a subnet that is currently in use elsewhere.

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  2. Well I don't know the Windows side of things, but as far as general networking goes... connect the crossover cable, give each interface an IP in the same subnet (preferably something that isn't used anywhere else, to avoid confusion) and setup whatever software you want to use to use those IPs.

    On the other hand, you could also just go out and buy a $50 gigabit switch, and throw it in between the two boxes and the router. I have a 5-port D-Link (consumer grade) unmanaged switch, and I've gotten sustained transfer rates of 950+Mbps over it. You only have two machines you're concerned about now... but what do you do when you want a third host on GigE?

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  3. I'd make sure I did the following:

    1. Designate a new neblock for the crossover cable (a /30 should be plenty).
    2. Use a cable that's at least 1.5 metres (as you can get pretty bad cross talk on gig links otherwise).
    3. Make sure that the relevant software has been configured to use the cross-over link
    4. Mark the cross-over cable, so it is hard to mistake for a straight-through cable.
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