mac pro ethernet 2 port not working

possible solution

I know this sounds unlikely, but often these issues can be fixed by simply unplugging your computer for a few minutes before plugging it back in and starting up. I would suggest giving it a try.

 

What does it say if you type "ifconfig" in Terminal.app?

 

Connect to what? Do you mean you have a DSL or cable modem on the other end of the cable, and you can't access the outside world?

Yes, it's a configuration issue.

Can you clarify what your network looks like? Is it correct to assume that you don't have a hub or switch, and you want to put your modem on one link and your NAS on the other?

 

Both my ports are working fine on my 2008 pm. One is for the internet and the other one goes to a writer.

 

writer = printer?

I actually don't know the immediate and practical use of a second LAN on a machine like this. Before the use of routers in the home were made pervasive, I had to add a second NIC card to share my internet with other computers via a HUB. Yeah.

 

That would explain what you see.

You don't need to get a router; the Mac can act as one.

First try turning on Internet Sharing in the Sharing settings, from Ethernet port 1 to Ethernet port 2. If that doesn't let your drive work on port 2, you will need to do some manual configuration of port 2 -- in that case, it might help to know what model NAS you have, in case it has some particular requirements.

 

Yes, typically, the router does that. With "Internet Sharing" turned on, the Mac should have been forwarding the DHCP between the NAS and router. However, typically, the router also doesn't care what ethernet port it's connected to. I am guessing that the router declined to provide DHCP service for the NAS, just as it declined to do so for the Mac port 2. If that is the case, adding an ethernet switch won't help you -- you would need a full-fledged IP router, and ones that do gigabit ethernet aren't cheap (you don't want to cut your disk access speed to 1/10 capacity).

Connecting the NAS to the Mac's port 2 isn't a bad idea for your setup, since it will make the full 1Gb/s link available to disk traffic, without competition from internet traffic. You can set up the Mac to provide DHCP service for the NAS on port 2. However, I've never done this, so I can't tell you exactly how to do that.

 

Ports 1 and 2

I think I may be having a similar problem: sometimes port 1 works and sometimes port 2; it's consistent across cable modem recycles.

If I power-cycle the TW RoadRunner-supplied cable modem (and sometimes when I restart my Xeon Mac Pro, 10.5.2), they usually switch:The port that worked in the last session (that is, before the restart(s)) stops working while the one that typically gave the IP address assignment message you get then starts to work.

I have a case open with the ever helpful Apple and am waiting to see if it's hardware... a new and pristine machine with no haxies etc., and permissions repaired daily etc.

I tried it with another RoadRunner modem and got the same behavior.

 

Fixed It!

I, too, had the problem with the ethernet port. It had a self assigned ip address. Apple has an article about it on this page: http://docs.info.apple.com/article.html?artnum=106879. I found that it wasn't enough to turn the cable modem off and unplug everything connected to it. I had to take out the modem's battery, which was easy to do. Then I put the battery back and put back the cable, etc., went to system preferences (with that ethernet port connected ), Advanced, Renew DHCP lease and clicked OK...and it connected after a few seconds.