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DHCP problems with Ethernet

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Marko Polo

Senior Member
I face strange problem with my Ethernet adapter from time to time. It cannot receive IP address, whilst WiFi works like a charm. I resolved the issue (don't remember how) but after Windows reinstall the problem returned. I tried uninstalling network adapter several times but that gave no result.
Tried executing

Code:
netsh winsock reset
netsh int ip reset
ipconfig /release
ipconfig /renew
ipconfig /flushdns

and the same thing. In the Event Viewer of the PC I see

Your computer was not assigned an address from the network (by the DHCP Server) for the Network Card with network address 0x00FF2C382080. The following error occurred: 0x79. Your computer will continue to try and obtain an address on its own from the network address (DHCP) server.

and in the router log there is

Code:
Sep 21 17:24:44 dnsmasq[5343]: using nameserver 8.8.8.8
Sep 21 17:24:44 dnsmasq[5343]: using nameserver 8.8.4.4
Sep 21 17:25:07 dnsmasq-dhcp[5343]: DHCPDISCOVER(br0) XX:XX:XX:XX:XX:XX
Sep 21 17:25:07 dnsmasq-dhcp[5343]: DHCPOFFER(br0) 192.168.1.49 XX:XX:XX:XX:XX:XX
Sep 21 17:25:09 dnsmasq-dhcp[5343]: DHCPDISCOVER(br0) XX:XX:XX:XX:XX:XX
Sep 21 17:25:09 dnsmasq-dhcp[5343]: DHCPOFFER(br0) 192.168.1.49 XX:XX:XX:XX:XX:XX
Sep 21 17:25:13 dnsmasq-dhcp[5343]: DHCPDISCOVER(br0) XX:XX:XX:XX:XX:XX
Sep 21 17:25:13 dnsmasq-dhcp[5343]: DHCPOFFER(br0) 192.168.1.49 XX:XX:XX:XX:XX:XX
Sep 21 17:25:21 dnsmasq-dhcp[5343]: DHCPDISCOVER(br0) XX:XX:XX:XX:XX:XX
Sep 21 17:25:21 dnsmasq-dhcp[5343]: DHCPOFFER(br0) 192.168.1.49 XX:XX:XX:XX:XX:XX
Sep 21 17:25:39 dnsmasq-dhcp[5343]: DHCPDISCOVER(br0) XX:XX:XX:XX:XX:XX
Sep 21 17:25:39 dnsmasq-dhcp[5343]: DHCPOFFER(br0) 192.168.1.49 XX:XX:XX:XX:XX:XX
Sep 21 17:26:12 dnsmasq-dhcp[5343]: DHCPDISCOVER(br0) XX:XX:XX:XX:XX:XX
Sep 21 17:26:12 dnsmasq-dhcp[5343]: DHCPOFFER(br0) 192.168.1.49 XX:XX:XX:XX:XX:XX
Sep 21 17:26:13 dnsmasq-dhcp[5343]: DHCPDISCOVER(br0) XX:XX:XX:XX:XX:XX
Sep 21 17:26:13 dnsmasq-dhcp[5343]: DHCPOFFER(br0) 192.168.1.49 XX:XX:XX:XX:XX:XX
Sep 21 17:26:22 dnsmasq-dhcp[5343]: DHCPDISCOVER(br0) XX:XX:XX:XX:XX:XX
Sep 21 17:26:22 dnsmasq-dhcp[5343]: DHCPOFFER(br0) 192.168.1.49 XX:XX:XX:XX:XX:XX
Sep 21 17:26:38 dnsmasq-dhcp[5343]: DHCPDISCOVER(br0) XX:XX:XX:XX:XX:XX
Sep 21 17:26:38 dnsmasq-dhcp[5343]: DHCPOFFER(br0) 192.168.1.49 XX:XX:XX:XX:XX:XX
Sep 21 17:28:04 dnsmasq-dhcp[5343]: DHCPDISCOVER(br0) XX:XX:XX:XX:XX:XX
Sep 21 17:28:04 dnsmasq-dhcp[5343]: DHCPOFFER(br0) 192.168.1.49 XX:XX:XX:XX:XX:YY
Sep 21 17:28:04 dnsmasq-dhcp[5343]: DHCPDISCOVER(br0) XX:XX:XX:XX:XX:YY
Sep 21 17:28:04 dnsmasq-dhcp[5343]: DHCPOFFER(br0) 192.168.1.104 XX:XX:XX:XX:XX:YY
Sep 21 17:28:04 dnsmasq-dhcp[5343]: DHCPREQUEST(br0) 192.168.1.104 XX:XX:XX:XX:XX:YY
Sep 21 17:28:04 dnsmasq-dhcp[5343]: DHCPACK(br0) 192.168.1.104 XX:XX:XX:XX:XX:YYcubical-wifi
Sep 21 17:28:06 dnsmasq-dhcp[5343]: DHCPDISCOVER(br0) XX:XX:XX:XX:XX:XX
Sep 21 17:28:06 dnsmasq-dhcp[5343]: DHCPOFFER(br0) 192.168.1.49 XX:XX:XX:XX:XX:XX
Sep 21 17:28:07 dnsmasq-dhcp[5343]: DHCPDISCOVER(br0) XX:XX:XX:XX:XX:XX
Sep 21 17:28:07 dnsmasq-dhcp[5343]: DHCPOFFER(br0) 192.168.1.49 XX:XX:XX:XX:XX:XX
Sep 21 17:28:11 dnsmasq-dhcp[5343]: DHCPDISCOVER(br0) XX:XX:XX:XX:XX:XX
Sep 21 17:28:11 dnsmasq-dhcp[5343]: DHCPOFFER(br0) 192.168.1.49 XX:XX:XX:XX:XX:XX
Sep 21 17:28:16 dnsmasq-dhcp[5343]: DHCPDISCOVER(br0) XX:XX:XX:XX:XX:XX
Sep 21 17:28:16 dnsmasq-dhcp[5343]: DHCPOFFER(br0) 192.168.1.49 XX:XX:XX:XX:XX:XX
Sep 21 17:28:25 dnsmasq-dhcp[5343]: DHCPDISCOVER(br0) XX:XX:XX:XX:XX:XX
Sep 21 17:28:25 dnsmasq-dhcp[5343]: DHCPOFFER(br0) 192.168.1.49 XX:XX:XX:XX:XX:XX
Sep 21 17:28:35 dnsmasq-dhcp[5343]: DHCPDISCOVER(br0) XX:XX:XX:XX:XX:XX
Sep 21 17:28:35 dnsmasq-dhcp[5343]: DHCPOFFER(br0) 192.168.1.49 XX:XX:XX:XX:XX:XX
Sep 21 17:29:02 dnsmasq-dhcp[5343]: DHCPDISCOVER(br0) XX:XX:XX:XX:XX:XX
Sep 21 17:29:02 dnsmasq-dhcp[5343]: DHCPOFFER(br0) 192.168.1.49 XX:XX:XX:XX:XX:XX
Sep 21 17:29:09 dnsmasq-dhcp[5343]: DHCPDISCOVER(br0) XX:XX:XX:XX:XX:XX
Sep 21 17:29:09 dnsmasq-dhcp[5343]: DHCPOFFER(br0) 192.168.1.49 XX:XX:XX:XX:XX:XX
Sep 21 17:29:09 dnsmasq-dhcp[5343]: DHCPREQUEST(br0) 192.168.1.104 XX:XX:XX:XX:XX:YY
Sep 21 17:29:09 dnsmasq-dhcp[5343]: DHCPACK(br0) 192.168.1.104 XX:XX:XX:XX:XX:YY cubical-wifi
Sep 21 17:29:10 dnsmasq-dhcp[5343]: DHCPDISCOVER(br0) XX:XX:XX:XX:XX:XX
Sep 21 17:29:10 dnsmasq-dhcp[5343]: DHCPOFFER(br0) 192.168.1.49 XX:XX:XX:XX:XX:XX
Sep 21 17:29:18 dnsmasq-dhcp[5343]: DHCPDISCOVER(br0) XX:XX:XX:XX:XX:XX
Sep 21 17:29:18 dnsmasq-dhcp[5343]: DHCPOFFER(br0) 192.168.1.49 XX:XX:XX:XX:XX:XX
Sep 21 17:29:34 dnsmasq-dhcp[5343]: DHCPDISCOVER(br0) XX:XX:XX:XX:XX:XX
Sep 21 17:29:34 dnsmasq-dhcp[5343]: DHCPOFFER(br0) 192.168.1.49 XX:XX:XX:XX:XX:XX
Sep 21 17:30:09 dnsmasq-dhcp[5343]: DHCPDISCOVER(br0) XX:XX:XX:XX:XX:XX
Sep 21 17:30:09 dnsmasq-dhcp[5343]: DHCPOFFER(br0) 192.168.1.49 XX:XX:XX:XX:XX:XX
Sep 21 17:30:11 dnsmasq-dhcp[5343]: DHCPDISCOVER(br0) XX:XX:XX:XX:XX:XX
Sep 21 17:30:11 dnsmasq-dhcp[5343]: DHCPOFFER(br0) 192.168.1.49 XX:XX:XX:XX:XX:XX
Sep 21 17:30:19 dnsmasq-dhcp[5343]: DHCPDISCOVER(br0) XX:XX:XX:XX:XX:XX
Sep 21 17:30:19 dnsmasq-dhcp[5343]: DHCPOFFER(br0) 192.168.1.49 XX:XX:XX:XX:XX:XX
Sep 21 17:30:35 dnsmasq-dhcp[5343]: DHCPDISCOVER(br0) XX:XX:XX:XX:XX:XX
Sep 21 17:30:35 dnsmasq-dhcp[5343]: DHCPOFFER(br0) 192.168.1.49 XX:XX:XX:XX:XX:XX
Sep 21 17:31:34 dnsmasq-dhcp[5343]: DHCPDISCOVER(br0) XX:XX:XX:XX:XX:XX
Sep 21 17:31:34 dnsmasq-dhcp[5343]: DHCPOFFER(br0) 192.168.1.49 XX:XX:XX:XX:XX:XX
Sep 21 17:31:36 dnsmasq-dhcp[5343]: DHCPDISCOVER(br0) XX:XX:XX:XX:XX:XX
Sep 21 17:31:36 dnsmasq-dhcp[5343]: DHCPOFFER(br0) 192.168.1.49 XX:XX:XX:XX:XX:XX
Sep 21 17:31:41 dnsmasq-dhcp[5343]: DHCPDISCOVER(br0) XX:XX:XX:XX:XX:XX
Sep 21 17:31:41 dnsmasq-dhcp[5343]: DHCPOFFER(br0) 192.168.1.49 XX:XX:XX:XX:XX:XX
Sep 21 17:31:49 dnsmasq-dhcp[5343]: DHCPDISCOVER(br0) XX:XX:XX:XX:XX:XX
Sep 21 17:31:49 dnsmasq-dhcp[5343]: DHCPOFFER(br0) 192.168.1.49 XX:XX:XX:XX:XX:XX
Sep 21 17:32:08 dnsmasq-dhcp[5343]: DHCPDISCOVER(br0) XX:XX:XX:XX:XX:XX
Sep 21 17:32:08 dnsmasq-dhcp[5343]: DHCPOFFER(br0) 192.168.1.49 XX:XX:XX:XX:XX:XX
Sep 21 17:35:14 dnsmasq-dhcp[5343]: DHCPREQUEST(br0) 192.168.1.104 XX:XX:XX:XX:XX:YY
Sep 21 17:35:14 dnsmasq-dhcp[5343]: DHCPACK(br0) 192.168.1.104 XX:XX:XX:XX:XX:YY cubical-wifi
Sep 21 17:35:31 dnsmasq-dhcp[5343]: DHCPDISCOVER(br0) XX:XX:XX:XX:XX:XX
Sep 21 17:35:31 dnsmasq-dhcp[5343]: DHCPOFFER(br0) 192.168.1.49 XX:XX:XX:XX:XX:XX
Sep 21 17:35:33 dnsmasq-dhcp[5343]: DHCPDISCOVER(br0) XX:XX:XX:XX:XX:XX
Sep 21 17:35:33 dnsmasq-dhcp[5343]: DHCPOFFER(br0) 192.168.1.49 XX:XX:XX:XX:XX:XX
Sep 21 17:35:38 dnsmasq-dhcp[5343]: DHCPDISCOVER(br0) XX:XX:XX:XX:XX:XX
Sep 21 17:35:38 dnsmasq-dhcp[5343]: DHCPOFFER(br0) 192.168.1.49 XX:XX:XX:XX:XX:XX
Sep 21 17:35:47 dnsmasq-dhcp[5343]: DHCPDISCOVER(br0) XX:XX:XX:XX:XX:XX
Sep 21 17:35:47 dnsmasq-dhcp[5343]: DHCPOFFER(br0) 192.168.1.49 XX:XX:XX:XX:XX:XX
Sep 21 17:36:05 dnsmasq-dhcp[5343]: DHCPDISCOVER(br0) XX:XX:XX:XX:XX:XX
Sep 21 17:36:05 dnsmasq-dhcp[5343]: DHCPOFFER(br0) 192.168.1.49 XX:XX:XX:XX:XX:XX
Sep 21 17:36:38 dnsmasq-dhcp[5343]: DHCPDISCOVER(br0) XX:XX:XX:XX:XX:XX
Sep 21 17:36:38 dnsmasq-dhcp[5343]: DHCPOFFER(br0) 192.168.1.49 XX:XX:XX:XX:XX:XX
Sep 21 17:36:40 dnsmasq-dhcp[5343]: DHCPDISCOVER(br0) XX:XX:XX:XX:XX:XX
Sep 21 17:36:40 dnsmasq-dhcp[5343]: DHCPOFFER(br0) 192.168.1.49 XX:XX:XX:XX:XX:XX
Sep 21 17:36:48 dnsmasq-dhcp[5343]: DHCPDISCOVER(br0) XX:XX:XX:XX:XX:XX
Sep 21 17:36:48 dnsmasq-dhcp[5343]: DHCPOFFER(br0) 192.168.1.49 XX:XX:XX:XX:XX:XX
Sep 21 17:37:04 dnsmasq-dhcp[5343]: DHCPDISCOVER(br0) XX:XX:XX:XX:XX:XX
Sep 21 17:37:04 dnsmasq-dhcp[5343]: DHCPOFFER(br0) 192.168.1.49 XX:XX:XX:XX:XX:XX
Sep 21 17:40:10 dnsmasq-dhcp[5343]: DHCPDISCOVER(br0) XX:XX:XX:XX:XX:XX
Sep 21 17:40:10 dnsmasq-dhcp[5343]: DHCPOFFER(br0) 192.168.1.49 XX:XX:XX:XX:XX:XX
Sep 21 17:40:12 dnsmasq-dhcp[5343]: DHCPDISCOVER(br0) XX:XX:XX:XX:XX:XX
Sep 21 17:40:12 dnsmasq-dhcp[5343]: DHCPOFFER(br0) 192.168.1.49 XX:XX:XX:XX:XX:XX
Sep 21 17:40:17 dnsmasq-dhcp[5343]: DHCPDISCOVER(br0) XX:XX:XX:XX:XX:XX
Sep 21 17:40:17 dnsmasq-dhcp[5343]: DHCPOFFER(br0) 192.168.1.49 XX:XX:XX:XX:XX:XX
Sep 21 17:40:25 dnsmasq-dhcp[5343]: DHCPDISCOVER(br0) XX:XX:XX:XX:XX:XX
Sep 21 17:40:25 dnsmasq-dhcp[5343]: DHCPOFFER(br0) 192.168.1.49 XX:XX:XX:XX:XX:XX
Sep 21 17:40:45 dnsmasq-dhcp[5343]: DHCPDISCOVER(br0) XX:XX:XX:XX:XX:XX
Sep 21 17:40:45 dnsmasq-dhcp[5343]: DHCPOFFER(br0) 192.168.1.49 XX:XX:XX:XX:XX:XX
Sep 21 17:41:16 dnsmasq-dhcp[5343]: DHCPDISCOVER(br0) XX:XX:XX:XX:XX:XX
Sep 21 17:41:16 dnsmasq-dhcp[5343]: DHCPOFFER(br0) 192.168.1.49 XX:XX:XX:XX:XX:XX
Sep 21 17:41:17 dnsmasq-dhcp[5343]: DHCPDISCOVER(br0) XX:XX:XX:XX:XX:XX
Sep 21 17:41:17 dnsmasq-dhcp[5343]: DHCPOFFER(br0) 192.168.1.49 XX:XX:XX:XX:XX:XX
Sep 21 17:41:26 dnsmasq-dhcp[5343]: DHCPDISCOVER(br0) XX:XX:XX:XX:XX:XX
Sep 21 17:41:26 dnsmasq-dhcp[5343]: DHCPOFFER(br0) 192.168.1.49 XX:XX:XX:XX:XX:XX
Sep 21 17:41:42 dnsmasq-dhcp[5343]: DHCPDISCOVER(br0) XX:XX:XX:XX:XX:XX
Sep 21 17:41:42 dnsmasq-dhcp[5343]: DHCPOFFER(br0) 192.168.1.49 XX:XX:XX:XX:XX:XX

The problem persists both with static IP assignment and with dynamic. I tried both with IPv6 enabled and without. No way.
Any suggestions? I assume this is dnsmasq problem, no?
 
Last edited:
"Any suggestions? I assume this is dnsmasq problem, no?

Hi Marko,


If it was, would you not get the same problems on wifi? As it is, your problem is only on Ethernet.

You say you previously resolved the issue and now have forgotten how you did it ( I know that feeling!), but it started up again when you reinstalled Windows. Could it be that you previously updated the driver for your Ethernet adapter on your Windows machine and you now need to go back and update to the latest driver again?

(Good idea to back up all your drivers with something like DriversBackup2, so if you need to reinstall Windows, you have a backup of all the drivers you previously had. It saves wasting days of your life searching the four corners of The Universe for drivers or trying to install ones the Microsoft incorrectly says are the right ones.)
 
Okay, but what should be probable troubleshooting steps in such cases?

Good question! I don't really know, but if it were my machine, I think I'd first check in Device Manager to see if there is a warning sign against the Ethernet adapter, and even if there wasn't, I'd try and find the latest driver for your version of Windows but leave it on the desktop for now (not installed). Then I'd turn off the wireless switch on the device, reboot it and see if it connected via Ethernet. If not, with wireless still turned off, I'd install the latest driver, reboot, and now see if it connected over Ethernet.

And if it still didn't work, I'd come back to the forum for more (and better) suggestions!


By the way, which version of Windows? Is it a PC or laptop? Which make and how old?
 
Are you limiting broadcast/multicast on your network?

Some sort of. I have white-list rules in my firewall for all of my devices, which looks like:

hPQ7C2P.png


So some broadcast traffic supposedly should be blocked. On the other hand, this does not prevent my another laptop working via Ethernet.

What NIC are you using?

The NIC we are speaking about is Realtek PCIe GBE Family Controller
Code:
Hardware IDs
PCI\VEN_10EC&DEV_8168&SUBSYS_85541043&REV_0C
PCI\VEN_10EC&DEV_8168&SUBSYS_85541043
PCI\VEN_10EC&DEV_8168&CC_020000
PCI\VEN_10EC&DEV_8168&CC_0200
 
Just to eliminate one possible cause, do you connect the other laptop with the same Ethernet cable? If not, swap the Ethernet cables over and see if the other laptop still connects over Ethernet, and check to see if the problem laptop now connects.

At worst, you'll be able to say it's not the cable.
 
I don't really know, but if it were my machine, I think I'd first check in Device Manager to see if there is a warning sign against the Ethernet adapter, and even if there wasn't, I'd try and find the latest driver for your version of Windows but leave it on the desktop for now (not installed). Then I'd turn off the wireless switch on the device, reboot it and see if it connected via Ethernet. If not, with wireless still turned off, I'd install the latest driver, reboot, and now see if it connected over Ethernet.

Thanks, man! ;) That was really the driver issue. I found another Realtek drivers and finally got IP.
For me it's unusual, cause they're quite generic Ethernet drivers which are the same across all devices, and usually default drivers which are shipped with Windows are better than vendor ones. This case is different.
Thanks everybody for your efforts.
 
Excellent; I'm so pleased I could help.

You might consider a drivers backup program but obviously be very, very careful about downloading anything free from sites such as CNET, Softpedia and all the similar sites that bundle PUPs with free software. I tend to only download from a developer's own site and then with great care, especially with free software. I use DriversBackup2 but it's a fair time since I downloaded it and if I wanted to download it again I'd try and check to see if it was still safe.

You know what they say: if an app or program is free, then you are the product.
 
Just a thought, but did you assign the static address outside of the DHCP range?

Nope, only from range.

Interesting, but the problem still persists, even when I use WiFi connection. I see these messages in my log up to now:

Your computer was not assigned an address from the network (by the DHCP Server) for the Network Card with network address 0x00FF2C382080. The following error occurred: 0x79. Your computer will continue to try and obtain an address on its own from the network address (DHCP) server.

I see them, but, finally the IP is assigned (not from the first attempt maybe). What that could be?
 
Do you have any idea how long it struggles before it gets assigned an IP address? Is it seconds, minutes or longer?

You said previously there was no problem when connecting by wifi; however, the problem is now also with wifi. Do that mean perhaps the problem did exist (before you updated the Ethernet adapter driver) but you didn't notice it, or has something changed and now wifi is as problematic as Ethernet?
 
Do you have any idea how long it struggles before it gets assigned an IP address?

No idea. How can it be estimated?

Do that mean perhaps the problem did exist (before you updated the Ethernet adapter driver) but you didn't notice it, or has something changed and now wifi is as problematic as Ethernet?

Very likely, 'cause address 0x00FF2C382080 says nothing to me and I dunno to which NIC this error was/is related . Very likely there were errors both with wired and wireless NICs, and now only with wireless.
 
So some broadcast traffic supposedly should be blocked. On the other hand, this does not prevent my another laptop working via Ethernet.
The Network Services Filter only blocks LAN to WAN traffic so it doesn't affect broadcasts which exist only within the local network.

No idea. How can it be estimated?
:confused: By looking at the times in the syslog.

Very likely, 'cause address 0x00FF2C382080 says nothing to me and I dunno to which NIC this error was/is related . Very likely there were errors both with wired and wireless NICs, and now only with wireless.
This is almost certainly a client issue and not a router issue. I've seen these sorts of messages before, but mostly they are from devices that have gone into "sleep" mode. Things like mobile phones or smart TV's. Rebooting the device usually sorts it out.

If you Google the error there are lots of reports for it with various solutions, but it's a fairly generic message.

P.S. Make sure you don't have both the wireless and the wired network adapters connected to the router at the same time.
 
Last edited:
By looking at the times in the syslog.
The problem is that syslog is overwritten when it reaches some limit. BTW, somewhere here I read that, despite disposable nature of log via GUI, old syslog messages are archived and put somewhere based on logrotate policy. Or I am mistaken?

I've seen these sorts of messages before, but mostly they are from devices that have gone into "sleep" mode.

Yeah, I think so too, that I am bring much panic here. Will follow the situation further.
 
The problem is that syslog is overwritten when it reaches some limit. BTW, somewhere here I read that, despite disposable nature of log via GUI, old syslog messages are archived and put somewhere based on logrotate policy. Or I am mistaken?
It's not as sophisticated as logrotate, but it does keep a copy of the current and previous log file in /jffs.
 

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