Troubleshooting network (not getting IP from DHCP)

Setup: cable internet -> modem -> ethernet cable -> DIR-655 wireless router -> ethernet cable (port 1) -> 3Com SuperStack II (port 1) -> 11 CAT5 ethernet cables to wall outlets (one end is wired to a modular plug, the other to the wall outlet) -> 11 ethernet cables -> 11 NICs/PCs (works, albeit very slowly since it's limited to the 3Com's 10Mbps connection).

Problem: I have 4 outlets in the DIR-655 that support 100/1000 and since only the first outlet is used (to the 3Com switch), I wanted to use the other 3 for the 3 computers that use internet the most. So I changed the setup to: cable internet -> modem -> ethernet cable -> DIR-655 wireless router -> ethernet cable to wall outlet -> ethernet cable -> NIC/PC (bypass the 3Com). My computer (Vista 64 Home Premium) first starts connecting/disconnecting then finally ends with unidentified network and an automatic private IP instead of the DHCP assigned IP. Only if I manually set the duplex to 10Mbps does it work.

Question: why can my computer connect via the 3Com switch to the router and get a dynamic IP but when I connect it directly to the DIR-655, it doesn't unless I set it manually back down to 10Mbps? I plug the computer directly into the DIR-655 and it gives me the full 100Mbps with dynamic IP.

 

What box is the DCHP, the DIR-655 box right? I'm guessing you've rebooted the router and all that too?

Hmm, you mentioned CAT5 cables but are they 4 pair CAT5e cables? If they are the cheapies it's probably trying to negotiate at 1Gbps but can't (cuz of the cables) and doesn't fall back. You mentioned it works fine directly connected but maybe the outlet in the wall isn't wired up for all 4 pairs?

 

The DIR-655 is the only DHCP. I've rebooted the modem, router, and computers. Sorry, to be specific they're CAT5E. How can you check if the wall is wired up for all 4 pairs?

 

You would have to take it off and check all the wires are connected.

When you plugged it in directly did it connect at 1Gbps or only 100Mbps? (basically asking is your NIC 10/100 or 1Gbps)

 

The NIC is 1Gbps and works when connected directly but through the wall only works at 10Mbps.

 

Sounds like the wall is only 4 wire cat3. If you have access to a line tester it would be easy to confirm. Some Nic's have a utility to check wiring. seen this on desktops but not NB.

 

I thought so too, but I pulled the wire out and they are listed as CAT5e. I have a wire tester but it only confirms the signals are straight (vs. crossed) and that they are going through correctly.

 

So do all 8 wires light up on the tester?

Checked all wires are punched down on the wall outlet.

 

Yes, all 8 wires light up on both ends and I physically checked the connections of the wall outlet / network cable. It's so weird that the wires work but only at 10Mbps...

 

Yea, this is a weird one. I'll say this much, the other day I was trying to set my PS3 (via it's Network Settings) to 1Gbps but for some reason it would not negotiate a connection with my E3000 Router with that setting. (Wouldn't get "connected")

What I had to do for things to work is set it back down to 100Mbps. What the issue may have been in my case I have no idea, because AFAIK the E3000 supports Gigabit connections as well as the PS3 <-- (I actually have the option to choose 1000 Mbps Full Duplex) so I was bewildered... now i'm wondering if this was due to my cabling; it's a possibility.

But at the same time my Server connects to the same E3000 Router @ 10Gbps. Yes 10Gbps not 1Gbps.

So idk what to say really...maybe swap out the cabling with new ones to test, making sure they are at least cat6 just to be sure?

Edit: * Notes; A good read I found on making the switch to Gigabit.

Also, I might be wrong...but it seems from this table on Wiki that you need at least cat6 cable to both Transmit AND Receive data with Gigabit throughput? Again, I could be wrong here.

 

I wonder if he has an older cable that may have the 568A wiring scheme that is throwing thing out. The 568B is the std today and supports GigE where the A does not. EIA/TIA 568A and EIA/TIA 568B

 

The Simple Answer:
CAT-5 is rated to 100M
CAT-5e is rated to 350M
CAT-6 and CAT6e is rated to 550M or 1000M depending on your source
CAT-7 is supposedly rated to 700M or presumably 1000M

Today there is no approved CAT-6 or CAT-7. While some folks are selling products they call Level 6 or 7, there aren't even specs for them, making CAT-5e the best available option. CAT-6 cable is being made with 23 gauge conductor wire as opposed to the slightly smaller 24 gauge for CAT-5e and also has a separator to handle crosstalk better.

Source: FAQs: CAT-5, CAT-5e, CAT-6, CAT-7 Patch Cables, difference between 10BASE-T, 100BASE-T and 1000BASE-T

Interesting, I didn't know that! Was wondering what the difference was. I'll check the wiring on the weekend. Though your link isn't valid.