Problems with DHCP using switch and router

Hello, I'm currently serving the US Army in Iraq and finalizing a network for my unit, so that the soldiers can have internet. We are on a satellite and there are 29 people connected. The current configuration has the satellite receiver (modem) connect to the uplink on the router. The router is set to DHCP and has its static information set correctly to communicate through the modem. In port 1 of the router is the uplink from the switch. My problem is that only a few people can automatically obtain IP's from the router and most cannot even ping it through the switch. This, clearly should not be the case.

I am using a Linksys Router Model: BEFSR81 and a Linksys switch, the EtherFast 4124 24-port Ethernet Switch Model No. EF4124.

Right now there are 29 people beating down my door to get internet and I'm lost at this point, any suggestions you can offer would be greatly appreciated.

This switch to router connection, is it done with a crossover cable? Or does the switch have a "uplink" port on it and you have connected with a regular patch cable to this port and the router?

What is the range of addresses available for dhcp to serve out? You will find this info in the lan configuration area.

There is no uplink port on the switch as it is supposed to recognize what is uplink and what is down. Both cables have worked for those computers that can see the router.



It is set to the default w/ a range of 40 (more than necessary, I know) starting with 192.168.1.100.

<b>I do believe that I have solved the problem.</b>
For some reason, computers not connected within ~12 ft that have the NIC configuration set to autodetect cannot renew the IP from the router's DHCP server and as a result, the computer automatically assigns a private IP. After changing the cards configuration to force 10Base/T Full Duplex, it can see the router and recieve its dynamic IP. For some reason, it will not do this on 100Base/T. Regardless, this manual setting of the NIC configuration seems to have solved the problem and has so far connected every computer that wasn't connected before. I still have about 20 systems that are not connected, but that's due to the lines not being hooked up to the individual boxes.

So, hopefully, this fixes everything - thanks to Wanderer2 for his response

Sounds like your wiring is wrong. Either it doesn't support 100mb [not cat5] or is miswired [doesn't have the correct pairs being used but one line from one pair and another line from another pair].

Connecting between equipment is different then connecting pcs to equipment. A uplink port allows you to use a regular patch cable which is straight thru. The uplink port does the cross connect for you. Otherwise you have to use a crossover cable. If a newer switch then it has the ability to detect and change to complete the connection [mdix I believe they call it]

The wiring is correct based on the standard for "straight-through" wires. The switch is new and has the ability to detect the uplink and configure itself accordingly. I have found that manually setting the configuration resolves the issue on most computers (22 thus far). However, something of note would be Hewlett Packard/Compaq laptops. For some reason, it appears as if they've, by default, installed the wrong drivers for the NIC - after changing to another driver, included w/in XP, the system can connect without difficulty.

I'm curious as to why it is only computers within close distance to the network can connect 100base/T and the rest must be manually configured to ten when the wiring <i>is</i> correct.

Like I said the only reasonable explaination is the wiring NOT being correct.

Usual reason is unbalanced pairs like I explained before. The colors may look right but if the pairs are split you get unbalanced pairs which results in excessive signal loss due to next and cross talk.

Something else to look at is WHERE the wires go. If passing near a lighting ballast or other EMF producting equipment that can knock your transmission rate down.

Cable tester will tell you what is going on with your wiring.

If you switch is a managed switch you can also look at the port stats and see what errors are occuring.

If setting the speed on the pcs you should also set it in the switch per port so the two match.