Having Ethernet Problems on My Network?

Karl00

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Whenever I connect a new computer to my network from a customer, Ethernet won't work. They'll be assigned 169.254 IP addresses. This has happened with the last three or four customer computers. Wireless will work fine though. Had one All-in-One PC where it wouldn't work replaced the HDD, and Ethernet worked fine then. I assumed malware but then another laptop arrived and noticed the same symptoms. It's not the cables. I've connected the computers directly to the modem/router unit. Also unplugged the modem/router for a minute plus with no improvement. Our workstations work fine. Even tried the same cable the workstations used and cables tested good with cable tester. Not sure what's going on.
 
The self signed apipa address (the 169.254.xxx.xxx) is what Windows gives itself when it boots up and arps for a DHCP server, and it doesn't get an answer.

So, there's a lack of connection between it, and your DHCP service. Find the break.
Wireless works fine you say, is this a wireless access point that passes along the same DHCP as a wired connection, or is it a wireless router running a separate internal IP network with its own DHCP service?

What make/model ISP gateway/modem?
What is doing the wireless? Make/model..if different from above.
 
If you assign an IP manually does it work? If it does then your DHCP isn't working correctly if it doesn't you either have a connection problem or a bad port.

Sent from my SM-G870W using Tapatalk
 
After manually assigning IP address to one of the newer machines, it will connect via Ethernet. It automatically assigns DNS servers 8.8.8.8 and 8.8.4.4 though.
 
It seems others are having DHCP problems with this router model. No matter what settings were tried, nothing worked but a restore. After a restore, DHCP is working at least for now.
 
Have you tried rebooting your router (which would reboot it's DHCP server)? It might be choking on handing out addresses to new devices it hasn't seen before. Maybe running out of available leases, etc.
 
What's handing out the DHCP addresses - Windows* or your router? Or...both? :eek:

Edit: When you say a 'network' and 'workstations', I'm assuming some kind of server here? If that's wrong - ignore me!
 
Another assumption: you are running out of free IP addresses. This happens if the lease time is set too high. Have had the same problem years ago. After reducing the by default one week lease time to one day everything is fine here.
 
Sounds like you need to take a deeper look at your network setup.

Nothing wrong with using the google DNS servers but it's concerning if you have no idea where they are being assigned from.

If manually assigning an address works you have a DHCP problem.

Track down your DHCP server likely your router and check it's config. As others have stated make sure you only have 1 DHCP server.



Sent from my SM-G870W using Tapatalk
 
Sounds like you need to take a deeper look at your network setup.

Nothing wrong with using the google DNS servers but it's concerning if you have no idea where they are being assigned from.

If manually assigning an address works you have a DHCP problem.

Track down your DHCP server likely your router and check it's config. As others have stated make sure you only have 1 DHCP server
Just on this point: If you (OP) do have a windows server, use it's own DNS, not Googles'.
 
I'll also suggest having segregated networks for your internal stuff and client systems, or even better separate VLANs for each port that you plug client systems into. The last thing you want is to boot up a client system on your internal network and discover that it's infected with something that aggressively looks for multiple vulnerabilities on the local LAN - including both your systems and any client systems you're working on.

Client systems are like client children - several years old and capable of spreading viruses everywhere they go.
 
Just on this point: If you (OP) do have a windows server, use it's own DNS, not Googles'.

And then set your forwarders to Google or OpenDNS or whatever provider :D

edit: typo - tpying is hard
 
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