DHCP FAILED

[george1421]

@jeremyvdv said in DHCP FAILED:

Great if you have any info
i do not understand … what do you want as information

Ok so the target computer should be sitting at the FOS Linux command prompt at the moment. Post the output of this command ip addr show Make sure the network adapter is plugged into the ethernet cable then issue the command. After issuing the ip addr show command issue uname -a Post both answers to this thread.

[jeremyvdv]

this is what I have:

[george1421]

@jeremyvdv Ok from the picture the network adapter appears to be UP as well as we can see a link light. I can see the driver is loaded and is talking to the card because we have a mac address.

At the FOS Linux command prompt lets key in this /sbin/udhcpc -i enp0s25 --now and see if we can pick up an IP address now.

[jeremyvdv]

That’s it

[Sebastian Roth]

@george1421 @jeremyvdv Probably a spanning tree issue?!

[jeremyvdv]

how to explain that works on a Spanning TREE problem?

[Tom Elliott]

@jeremyvdv Spanning tree enables the ports to wait for a period of time between link up/link down before the switch will pass the information to the machine in case there’s a link connected back to itself on the switch.

This up/down time can be around 27 seconds in normal Spanning tree mode. This would explain why during the automated portion the device cannot get a link or IP, but once at the terminal and restarting the networking it will pick it up.

If your network is using spanning tree, if you can do so, disable it, or if not it’s best to use one of the Fast/Rapid stp methodologies as their up/down time is much more significantly reduced.

[jeremyvdv]

do you want to find out by
“or if not it’s best to use one of the Fast/Rapid stp methodologies as their up/down time is much more significantly reduced.”

Thanks

[george1421]

@jeremyvdv said in DHCP FAILED:

That’s it

This is what I wanted to see, to see if TIME fixed the problem. As the others have said its probably a spanning tree issue. Check with your network infrastructure people to see if they can turn on one of the fast spanning tree protocols on your network switches.

Another test would be to place a dumb (umanaged cheap switch) between the building switch and the target computer. If the system boots and imaging fine then its surely is either spanning tree or green ethernet settings causing the problem.

I do find it strange that if it is spanning tree, why didn’t the dell have the same problem? Is the dell possibly plugged into a different network switch?

[jeremyvdv]

No The dell is on the same switch.

That’s why I have a doubt about the idea of ​​the spanning tree.

And I’m pretty sure the spanning tree is off

[george1421]

@jeremyvdv Do you have an inexpensive unmanaged switch you can place between the target computer and the building switch to test?

[jeremyvdv]

Not at the moment but I will find that.

I keep you informed

[jps]

I have had the same problem with two machines. I found out that it came from the flow of the lan. I’ve had to decrease it to 100 Mb/s and it works after that. A suggestion.

[jeremyvdv]

Hello

This is a problem of config switch.
It’s a swtich Level3.

On one AC port works and not on the other.

I send you the config of its ports for info

Thank you for your help