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Two Windows PCs Connected Via Ethernet Not Able to Get a Valid IP Address

I have a small business client who used Verizon FIOS with a static IP address.

The FIOS modem is plugged into the WAN port on a Cisco/Linksys E2500 router, which is running DHCP. One of the LAN ports is connected to a Netgear GS2015 Gigabit Switch, which then feeds the signal out to 3 desktop PCs and and 2 Cisco IP 303 phones.

Everything has been working fine, but today they started having network connectivity issues so I stopped by to troubleshoot.
My laptop and phone & tablet connect to the Wifi with no problems at all, but 2 out of the 3 PCs plugged into the LAN ports on the Netgear switch do not get a valid IP addresses (although they were working fine last week).

I would conclude that the something was wrong on the wired ports, but how come the Cisco phones seem to have no problem connecting to the LAN and getting a working dial tone? And 1 of the 3 desktop PCs does manage to get a valid IP address and can connect to the internet just fine.

Network troubleshooter on one of the problematic Win 8.1 PCs gave the message, “The default gateway is not available.” The default gateway is the Linksys router on 192.168.0.1. Not surprisingly I cannot ping 192.168.0.1 from either PC.

Thanks in advance.
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Jackie Man
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The problem is from your Netgear switch which is not fully compatabile with your Linksys router which acts as a DHCP server.
Maybe you are running out of addresses?

A DHCP scope only ever has a limited number of IP addresses to dole out, and once assigned cannot be used until to lease has expired. If you have a cellphone connect as someone wanders through, and the DHCP lease is set to a week, then that IP cannot be used by another device for a week. You can quickly chew through a lot of addresses.

Check on the E2500. Perhaps you can make the DHCP range larger?  If not, maybe decrease the lease time?  The downside of the will be more frequent IP changes on the client machines, and a tiny bit more traffic.
Hi There,

Prima facie, the issue seems to be with the Netgear switch connecting to router.
Kindly confirm the below:

i)
DHCP scope defined on your WiFi router.

ii)
Have you tried swapping the working desktops/ IP phones on the affected LAN ports?

iii)
Have you tried connecting another workstation/laptop on the affected ports?
You say they get an invalid IP address but you don't say what they got. Open a command prompt and do a ipconfig /release followed by a ipconfig /renew and post the results. What IP address did they get?
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Malmensa. Good thought, but it is not an issue of DHCP exhaustion. There are 100 available addresses (and there are only about 10 devices) with a lease time of 24 hours. Also, wireless devices receive valid IP addresses just fine.
LockDown32. The problematic PCs are receiving standard APIPA addresses of 169.X.X.X.
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Ian Arakel. Why assume the issue is with the Netgear switch? This is a low-end unmanaged switch. It does not even have DHCP capability.

The currently set DHCP scope on the LInksys router is 192.168.0.100 - 192.168.0.199.

I plugged in my Windows 7 laptop using into one of the ports on the Netgear switch and it too got an unusable 169.x.x.x APIPA address.
Thanks Lockdown32. I did not set any VLANs on the Linksys router.

I will try resetting the IP Stack when I get on site in about 2 hours.
Resetting the IP stack did not resolve the issue.
Are you sure the 1 working PC and the 2 phones are actually getting an IP address or are they maybe using an IP address they got whose lease hasn't expired yet? Have you tried turning off the 1 PC and 2 Phones to see if they get a DHCP address when they come back up?
I decided to remove the Linksys E2500 from the equation and instead use the Verizon-supplied Wifi router (that we were initially going to return to Verizon).

Still having the same problem with those 2 desktop PCs. And any devices connected via Wifi are working just fine.

I've rebooted the Cisco phone multiple times. Their IPs are set statically.
OK. What about the one PC that is working? Is it static or dynamic? What happens when you turn it off and back on? Really the two phones are moot because they are static and we are working on a DHCP issue....
In looking at the diagram I had the E2500 was the DHCP server. DHCP, as a result, should have been turned off on the FIOS router. Did you turn it back on when you removed the E2500?
That one working PC is using DHCP. No idea why it has no problem getting a usable IP address! And yes, I turned on DHCP on the Verizon router.

In any case, I couldn't deal anymore. I went out and bought USB Wifi adapters and now the 2 problematic desktops are happily connected to the network via a Wifi connection.
Whatever works!
Thanks for the assistance!