# Solved: Network card can't detect crossover cable



## Agile (Jan 6, 2010)

Hello,

Im running windows xp on two different computers (a PC and a laptop) and for some reason when i plug in the crossover network cable, neither my laptop or my PC can see it. It just says that a network cable is unplugged. This is strange because if I connect a non cross over one (regular cat5) it sees it just fine.

any ideas why this might be happening? the cable is brand new.


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## TerryNet (Mar 23, 2005)

Even new cables are sometimes defective.

If either NIC is auto-sensing (most in the last few years are) the straight cable should work fine.


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## Agile (Jan 6, 2010)

Thats true it might be defective.

How would i check if it is auto sensing or not?

A straight cable before gave me the issue of limited connectivity, but I never checked any of the auto sensing features.

what Im trying to do overall is connect the PC to the laptop to share the laptops wireless connection. I was under the impression I needed a crossover cable for this...am I wrong?


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## JohnWill (Oct 19, 2002)

If either of the machines has a gigabit Ethernet port, they are auto-MDX by definition.


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## prunejuice (Apr 3, 2002)

JohnWill said:


> If either of the machines has a gigabit Ethernet port, they are auto-MDX by definition.


That's interesting. How does that work?


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## JohnWill (Oct 19, 2002)

prunejuice said:


> That's interesting. How does that work?


Nature of the beast. Gigabit uses all 8 wires, and the chipsets that support it. Auto-MDX is an feature of gigabit, I've never seen a gigabit port that didn't include it.

[WEBQUOTE="http://en.wikipedia.org/wiki/Medium_dependent_interface"]*Medium dependent interface crossover (MDIX)* (the X representing crossover) is a female 8P8C port connection on a computer, router, hub, or switch. Straight through cables connect pins 1 & 2 (transmit) on an MDI device to pins 1 & 2 (receive) on an MDIX device. Similarly pins 3 & 6 are receive on an MDI device and transmit on an MDIX device. The X refers to the fact that transmit wires on an MDI device must be connected to receive wires on an MDIX device. As a rule, end stations (i.e., PCs or workstations) and routers use an MDI interface, hubs and switches use MDIX interfaces. Newer routers, hubs and switches (including some 10/100, *and all 1 Gigabit or 10 Gigabit devices*) use Auto MDI/MDIX to automatically switch to the proper configuration once a cable is connected. The other four wires are used but are not crossed since Auto MDI/MDIX is mandatory at the higher speeds. See Ethernet over twisted pair for more details on cables and standards. Some Routers and other devices have an uplink switch to go back and forth between MDI and MDIX on a specific port[/WEBQUOTE]


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## TerryNet (Mar 23, 2005)

> How would i check if it is auto sensing or not?


Sometimes the specs for the computer or the ethernet will say "auto-sensing" or "MDI/MDIX." Or, as John said, all gigabit (1000/100/10 Mbps) adapters seem to be.

When you connect two computers directly there is no Dhcp server so Windows assigns an APIPA (IP of form 169.254.x.y). If you connect a computer to a router (or to an ISP directly with a modem) you should get an IP assigned by a Dhcp server; if no Dhcp server is found the resulting APIPA indicates a problem. Windows seems to assume that you always want internet access so anytime it sees that an APIPA was assigned it warns about "limited connectivity." In short, when connecting two computers directly ignore "limited connectivity."

Here's a way to see if the two computers can communicate. If all the pings fail it is probably because of a firewall blocking, but could also be a cable or NIC problem. If the pings fail one direction only it is almost definitely a firewall.

To open a Command Window: Start - Run - cmd (command in 98SE) - OK
(if Run not on Vista's or 7's Start menu, just type cmd in the Search box)

To determine a computer's IP address: open a Command Window and type
ipconfig

Now for some troubleshooting:

1. On each PC open a Command window and type
ping IPofOther (where IPofOther is the IP address of the other PC)

Do you get Replies, or do you get packets lost?

If you got Replies,

2. Do the same ping except use the Computer Name of the other computer:
ping NameOfOtherPC

Replies or lost packets?


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## prunejuice (Apr 3, 2002)

JohnWill said:


> Nature of the beast. Gigabit uses all 8 wires, and the chipsets that support it. Auto-MDX is an feature of gigabit, I've never seen a gigabit port that didn't include it.


Good to know. Thanks.


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## Agile (Jan 6, 2010)

The NICs are -> PC: Realtek RTL8139 Family PCI fast Ethernet NIC
Laptop: Broadcom NetXtreme Gigabit Ethernet

Ipconfig for Laptop:

Ethernet adapter Wireless Network Connection 2:

Connection-specific DNS Suffix . : phub.net.cable.rogers.com
IP Address. . . . . . . . . . . . : 192.168.0.193
Subnet Mask . . . . . . . . . . . : 255.255.255.0
Default Gateway . . . . . . . . . : 192.168.0.1

Ethernet adapter Local Area Connection 3:

Connection-specific DNS Suffix . :
Autoconfiguration IP Address. . . : 169.254.188.188
Subnet Mask . . . . . . . . . . . : 255.255.0.0
Default Gateway . . . . . . . . . :

ipconfig for Pc:

Ethernet adapter Local Area Connection 7:

Connection-specific DNS Suffix . :
Autoconfiguration IP Address. . . : 169.254.197.55
Subnet Mask . . . . . . . . . . . : 255.255.0.0
Default Gateway . . . . . . . . . :

I can ping by ip address but not by computer name.


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## TerryNet (Mar 23, 2005)

> I can ping by ip address but not by computer name.


That's probably a firewall issue.

You at least have basic communication, so you could try bridging the connections on the laptop to see if you have enough communication to get internet access on the desktop.


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## JohnWill (Oct 19, 2002)

Let's see this for each of the machines.

Hold the *Windows* key and press *R*, then type *CMD* then press *Enter* to open a command prompt:

In the command prompt window that opens, type type the following commands, one at a time, followed by the _*Enter*_ key:

_Note that there is a space before the -n or the /ALL, but there is *NOT* a space after the - or / in the following commands._

NBTSTAT -n

IPCONFIG /ALL

Right click in the command window and choose *Select All*, then hit *Enter* to copy the contents to the clipboard.
Paste the results in a message here.

If you are on a machine with no network connection, use a floppy, USB disk, or a CD-RW disk to transfer a text file with the information to allow pasting it here.


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## Agile (Jan 6, 2010)

Laptop
NBTSTAT:

Local Area Connection 3:
Node IpAddress: [169.254.188.188] Scope Id: []

NetBIOS Local Name Table

Name Type Status
---------------------------------------------
LAPTOP2 <00> UNIQUE Registered
LAPTOP2 <20> UNIQUE Registered
MSHOME2 <00> GROUP Registered
MSHOME2 <1E> GROUP Registered
MSHOME2 <1D> UNIQUE Registered
..__MSBROWSE__.<01> GROUP Registering

Wireless Network Connection 2:
Node IpAddress: [192.168.0.193] Scope Id: []

NetBIOS Local Name Table

Name Type Status
---------------------------------------------
LAPTOP2 <00> UNIQUE Registered
LAPTOP2 <20> UNIQUE Registered
MSHOME2 <00> GROUP Registered
MSHOME2 <1E> GROUP Registered
MSHOME2 <1D> UNIQUE Registered
..__MSBROWSE__.<01> GROUP Registering

ipconfig:

Windows IP Configuration

Host Name . . . . . . . . . . . . : LAPTOP2
Primary Dns Suffix . . . . . . . :
Node Type . . . . . . . . . . . . : Broadcast
IP Routing Enabled. . . . . . . . : No
WINS Proxy Enabled. . . . . . . . : No
DNS Suffix Search List. . . . . . : phub.net.cable.rogers.com

Ethernet adapter Local Area Connection 3:

Connection-specific DNS Suffix . :
Description . . . . . . . . . . . : Broadcom NetXtreme Gigabit Ethernet
Physical Address. . . . . . . . . : 00-16-D3-25-1E-96
Dhcp Enabled. . . . . . . . . . . : Yes
Autoconfiguration Enabled . . . . : Yes
Autoconfiguration IP Address. . . : 169.254.188.188
Subnet Mask . . . . . . . . . . . : 255.255.0.0
Default Gateway . . . . . . . . . :

Ethernet adapter Wireless Network Connection 2:

Connection-specific DNS Suffix . : phub.net.cable.rogers.com
Description . . . . . . . . . . . : NETGEAR 108 Mbps Wireless PC Card WG
511T
Physical Address. . . . . . . . . : 00-0F-B5-62-2A-A4
Dhcp Enabled. . . . . . . . . . . : Yes
Autoconfiguration Enabled . . . . : Yes
IP Address. . . . . . . . . . . . : 192.168.0.193
Subnet Mask . . . . . . . . . . . : 255.255.255.0
Default Gateway . . . . . . . . . : 192.168.0.1
DHCP Server . . . . . . . . . . . : 192.168.0.1
DNS Servers . . . . . . . . . . . : 192.168.0.1
Lease Obtained. . . . . . . . . . : Tuesday, January 12, 2010 6:05:13 PM

Lease Expires . . . . . . . . . . : Wednesday, January 13, 2010 6:05:13
PM

PC

NBTSTAT:

Local Area Connection 7:
Node IpAddress: [169.254.197.55] Scope Id: []

NetBIOS Local Name Table

Name Type Status
---------------------------------------------
COMPZORR <00> UNIQUE Registered
COMPZORR <20> UNIQUE Registered
MSHOME <00> GROUP Registered
MSHOME <1E> GROUP Registered

ipconfig:

Windows IP Configuration

Host Name . . . . . . . . . . . . : COMPZORR
Primary Dns Suffix . . . . . . . :
Node Type . . . . . . . . . . . . : Unknown
IP Routing Enabled. . . . . . . . : No
WINS Proxy Enabled. . . . . . . . : No

Ethernet adapter Local Area Connection 7:

Connection-specific DNS Suffix . :
Description . . . . . . . . . . . : Realtek RTL8139 Family PCI Fast Ethernet NIC #2
Physical Address. . . . . . . . . : 00-40-05-82-5E-9A
Dhcp Enabled. . . . . . . . . . . : Yes
Autoconfiguration Enabled . . . . : Yes
Autoconfiguration IP Address. . . : 169.254.197.55
Subnet Mask . . . . . . . . . . . : 255.255.0.0
Default Gateway . . . . . . . . . :


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## JohnWill (Oct 19, 2002)

Connect the two machines with a crossover Ethernet cable. If one or both of the machine have gigabit adapters or auto-MDX ports, an Ethernet patch cable will do the job.

Configure the machines as follows.

PC #1:
IP address: 192.168.9.1
Subnet Address: 255.255.255.0

PC #2:
IP address: 192.168.9.2
Subnet Address: 255.255.255.0

Leave the Default Gateway and DNS Server addresses blank.

Make sure any firewalls are configured to put the 192.168.9.x subnet in the trusted zone.

Finally, you'll have to enable file/print sharing on the machines and actually share one or more folders or drives.

Here's a page that describes the process in detail: http://www.howtodothings.com/computers-internet/how-to-connect-2-pcs-directly


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## Agile (Jan 6, 2010)

Okay it's working now, I can see the other computer and it can see me, and I can access files and such. Thanks a lot for the help!

One more question though, I want to share my wireless connection but when i go to set sharing on it tells me that it says that it will set my lan to 192.168.0.1. will this affect my wireless network? it is also using the 192.168.0.x range.


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## TerryNet (Mar 23, 2005)

First, you want to go back to dynamic addresses.

Then bridge the wireless and ethernet connections.

The other choice is to change the LAN subnet on the router (e.g., to 192.168.3.x) and enable ICS on the internet connection.


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## Agile (Jan 6, 2010)

Awesome!! everything works now!

Thank you so much guys, I really appreciate the help!

now i can return that cross over cable because it turns out i dont even need it.


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## TerryNet (Mar 23, 2005)

A double success!  You're welcome; we're glad we could help.


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