can't connect mac to internet through ethernet at work!

[Caroline]

Hey Guys,

I posted this weekend about not being able to get one of my computers running through a switch. I have just tried troubleshooting and found that the issue probably isn't the switch, I just can't get this computer to connect properly. Here's the setup:

1) ethernet port from wall connects to VoIP phone, the port on the phone is called 10/100/1000 SW
2) ethernet cable from phone to PC, port on phone is called 10/100/1000 PC
3) a third port, AUX is unoccupied

Computer 1: works! If the ethernet cord from #2 is plugged in I instantly get the following fields occupied in network settings (they are empty before the cable is plugged in or when I remove the cable)

conf. IPv4: using DHCP
IP: 128.205.92.11
subnet: 255.255.248.0
router: 128.205.95.254

In advanced tab:
DNS: 128.205.106.106, 128.205.106.1, 128.205.1.2, 128.205.32.8

Proxies: bypass: *.local, 169.254/16

Computer 2: won't connect to internet, I get the following:
configure IPv4: using DHCP
IP: 169.254.30.198
subnet: 255.255.0.0
no DNS listed
Proxies: *.local, 169.254/16

Here's the funny thing, I can see the local computers on my network and access them, even though I can't get on the internet. If the cable is pulled they disappear (important only because this computer is also configured to connect with wi-fi, in this case I have turned off wi-fi entirely).

Any suggestions? This is driving me crazy and the IT person here knows zip about macs, he wants to reconfigure computer 2 to work with DHCP, whatever that means.

[mattkime]

i suspect that the dns values need to be entered manually. copy them from computer 1 to 2.

---

scratch that, you're right, its not getting crap.

[btfc]

If you connect Computer 2 to the wall jack, can you connect?

[onthedownlow]

Have him check the 'real switch' settings (if appropriate, per policy) that the data jack is actually wired to. Perhaps the (managed?) switch is configured to only allow two devices to obtain an IP address, per data jack (this keeps people from hooking up a dozen devices per jack, etc.)

[JoeH]

mattkime wrote:
i suspect that the dns values need to be entered manually. copy them from computer 1 to 2.

That probably will not help since the IP address beginning with 169 indicates Mac #2 is not even connecting to the DHCP server to get an address. EIther the ethernet port is not active, is bad, or the DHCP server is rejecting it from connecting. Does Mac #2 get an IP address if it is plugged directly into the network port with the VOIP phone disconnected?

As for the IT person wanting to configure Mac #2 for DHCP, it appears to already be set to use that.

[Caroline]

OK, so I manually entered the DNS numbers but this didn't work. I also tried to connect directly from the wall to the computer. Again, this did not work. I've been told this wouldn't work, but I was able to do this previously to get a connection in my office before I had a VoIP phone.

[GGD]

Those IP addresses for the computer that does connect are not in one of the local IP ranges, they're real external IPs, and are registered to the University of Buffalo.

Are you at SUNY Buffalo, or is your IT dept somehow using an external range of IP addresses that don't belong to them as their local IP range for their router?

Many universities require that a computer's MAC address be "registered" with them before they will assign it an IP via DHCP. This might be your problem.

Has computer #2 ever been successfully connected via Ethernet from any place on this network?

[Caroline]

Dang, you tracked me down. I am at SUNY Buffalo. I thought about whether the mac address is registered, but I don't believe I did this for the older computer (that does connect). Let me go back and see if this is the case.

One of these computers was connected in my office but I honestly don't remember which (it was the one I unpacked first). I have since gotten a new computer that works well.

[Paul F.]

I"m suspecting your router or VOIP device is misconfigured...
You're getting that "public" IP address from your DHCP server on machine #1.

Machine #2, I would clear out all the settings, switch it TEMPORARILY to "DHCP with manual address"... preferably with the IT guy's permission and support so he can give you an IP number to put in that's not currently in use so you can troubleshoot.

I would also clear out any "proxy" settings, (#2 has that "Proxies: *.local, 169.254/16" line), unless your IT guy says to keep it...

Based on the other thread, I agree with C(-)ris.... your IT guy IS an idiot.. but a necessary one to get this stuff working.

[JoeH]

I would also clear out any "proxy" settings, (#2 has that "Proxies: *.local, 169.254/16" line), unless your IT guy says to keep it...

I would leave them alone, those appear to be default settings even without any proxy settings being enabled. I have the same on my computers, unless you are told to set up proxy settings it is best to leave that area alone.