Erratic periodic event where there is no recognition of networking hardware at boot time

ericmarceau · May 19, 2026, 3:31am

Every now and then, when I boot, my Desktop environment results in a state that there is no recognized network interface and therefore no access to the Internet!

I should be able to have the following report correctly,

ifconfig enp2s0

but, unfortunately, it always says that it doesn’t recognize that interface!

I must sadly report that every time that happens, having tried a few things that failed, I am always forced to restart the computer (specifically “restart”, not “shutdown” then reboot).

I saw in another post that the following should report as this,

# cat /run/network/ifstate

enp2s0=enp2s0
lo=lo

but, when I have a problem, that only reports

lo=lo

Is there any one particular service that I need to restart to restore proper neworking?

I tried the following to no effect:

31977  systemctl restart systemd-user-sessions
31978  systemctl restart systemd-user-sessions.service
31979  systemctl status systemd-user-sessions.service
31986  systemctl start networking.service
31987  systemctl restart systemd-networkd
31989  systemctl restart networking.service
31991  systemctl restart systemd-hostnamed.service
31993  systemctl restart NetworkManager.service

ugnvs · May 19, 2026, 7:24am

That behaviour resembles some symptoms exhibited by slowly dying electronic components. You see, micro-cracks, old capacitors, etc. can prevent some parts from being started/recognised when a system has cooled down. As soon as the system becomes warm, the problem magically eliminates itself.

pavlos · May 19, 2026, 1:37pm

my pc reports lo=lo but I have network working.

I would not check /run dir, it is better to check ifconfig or ip a

ugnvs · May 19, 2026, 2:55pm

May be

rediscover network interface sudo udevadm trigger --subsystem-match=net
verify that device was discovered ls -1 /sys/class/net/
not sure if interface should be brought up and/or udev rules reloaded
restart network service sudo systemctl restart NetworkManager

ericmarceau · May 19, 2026, 7:48pm

Thank you, Pavlos. I normally use ifconfig, but it was coming up empty, so I went looking for alternate things to look at to help identify relevant symptoms or diagnose the root cause.

pavlos · May 19, 2026, 8:02pm

grep <interface> /var/log/syslog there should be some chatter when the interface picks/renews an ip. My interface is enp3s0, here’s a portion of syslog.

May 19 07:39:22 cw avahi-daemon[881]: New relevant interface enp3s0.IPv6 for mDNS.
May 19 07:39:22 cw avahi-daemon[881]: Registering new address record for fe80::78dd:a3b7:9a6e:14dc on enp3s0.*.
May 19 07:39:22 cw NetworkManager[884]: <info>  [1779201562.9035] dhcp4 (enp3s0): state changed new lease, address=10.0.0.41
May 19 07:39:22 cw avahi-daemon[881]: Joining mDNS multicast group on interface enp3s0.IPv4 with address 10.0.0.41.
May 19 07:39:22 cw avahi-daemon[881]: New relevant interface enp3s0.IPv4 for mDNS.
May 19 07:39:22 cw avahi-daemon[881]: Registering new address record for 10.0.0.41 on enp3s0.IPv4.
May 19 07:39:22 cw NetworkManager[884]: <info>  [1779201562.9049] device (enp3s0): state change: ip-config -> ip-check (reason 'none', sys-iface-state: 'managed')
May 19 07:39:22 cw NetworkManager[884]: <info>  [1779201562.9072] device (enp3s0): state change: ip-check -> secondaries (reason 'none', sys-iface-state: 'managed')
May 19 07:39:22 cw NetworkManager[884]: <info>  [1779201562.9073] device (enp3s0): state change: secondaries -> activated (reason 'none', sys-iface-state: 'managed')
May 19 07:39:22 cw NetworkManager[884]: <info>  [1779201562.9078] policy: set 'Wired connection 1' (enp3s0) as default for IPv4 routing and DNS
May 19 07:39:22 cw NetworkManager[884]: <info>  [1779201562.9082] device (enp3s0): Activation: successful, device activated.
May 19 07:39:22 cw systemd-resolved[763]: enp3s0: Bus client set search domain list to: lan
May 19 07:39:22 cw systemd-resolved[763]: enp3s0: Bus client set default route setting: yes
May 19 07:39:22 cw systemd-resolved[763]: enp3s0: Bus client set DNS server list to: 10.0.0.1

new lease every 8m

May 19 08:01:52 cw NetworkManager[884]: <info>  [1779202912.9044] dhcp4 (enp3s0): state changed new lease, address=10.0.0.41
May 19 08:09:22 cw NetworkManager[884]: <info>  [1779203362.9088] dhcp4 (enp3s0): state changed new lease, address=10.0.0.41

My firewall (pfsense) has lease time 900s, that’s 15m.
But DHCP renews every 1/2 of that time, so about 8m

ericmarceau · May 19, 2026, 8:45pm

Scary thought! I just reviewed my docs and my ASUS M4A78-E motherboard has integrated networking.

So …

If my inxi -Fxxx reports

Network:
  Device-1: Qualcomm Atheros AR8121/AR8113/AR8114 Gigabit or Fast Ethernet
    vendor: ASUSTeK driver: ATL1E v: N/A pcie: speed: 2.5 GT/s lanes: 1
    port: ec00 bus-ID: 02:00.0 chip-ID: 1969:1026 class-ID: 0200

that means that I need an expansion card for one of my PCI slots, and that it should be PCIe and rated 2.5 Gb/s.

Is that correct? [1]

If so, this item should work, correct? [2]

PCIe Slot to RJ45 USB 3.0 PCIe Expansion Card,with Gigabit Ethernet Controller PCI Express Adapter for Desktop PC

Also, I should be plugging that (or similar) into one of the two “short” white PCIe x1 slots shown in the below image. Correct? [3]

Once the new card is installed, I should then be able to do something to tell the system to ignore the on-board network interface, currently known as enp2s0. Correct? [4]

ugnvs · May 19, 2026, 9:06pm

Hello, Eric! I do not want to mislead you for I have not assembled or upgraded any desktop for about a decade. IMHO, you can use any standard 1 Gb expansion card for any slot. (Tip: do not neglect to consult with Linux hardware compatibility lists.)
Surely, you can disable old interface in NetworkManager or in another way, but to me it is enough just to pull patchcord out of its socket.

pavlos · May 19, 2026, 9:15pm

Maybe the onboard nic goes into deep sleep and loses connectivity.

Suggestion: pcie_aspm=off in boot parms.

like GRUB_CMDLINE_LINUX_DEFAULT="quiet splash pcie_aspm=off"

sudo update-grub
sudo reboot

this should prevent the onboard nic from going to deep sleep.

IMO, you dont need a 2.5G card. But if you buy a card, the x1 slot (shortest pcie) is ok. You unplug the rj45 from the onboard and plug it on the pcie card. ifconfig will tell you the new card interface (it will not be enp2s0)

ericmarceau · May 19, 2026, 10:23pm

So, Pavlos, are you saying that to get 1 Mbs Ethernet on the RJ45, I could use a lower grade PCI (2?) card in the PCI_1 or PCI_2 slots?

ericmarceau · May 19, 2026, 10:36pm

I tried to extract entries from syslog to reproduce the kind of report (excerpt?) you gave there, for a recognized and functional interface. My report is below. Are the differences mostly due to different OS version running?

May 19 15:13:35 OasisMega1 avahi-daemon[954]: New relevant interface enp2s0.IPv4 for mDNS.
May 19 15:13:35 OasisMega1 avahi-daemon[954]: Joining mDNS multicast group on interface lo.IPv4 with address 127.0.0.1.
May 19 15:13:35 OasisMega1 avahi-daemon[954]: New relevant interface lo.IPv4 for mDNS.
May 19 15:13:35 OasisMega1 avahi-daemon[954]: Network interface enumeration completed.
May 19 15:13:35 OasisMega1 avahi-daemon[954]: Registering new address record for 192.168.0.12 on enp2s0.IPv4.
May 19 15:13:35 OasisMega1 avahi-daemon[954]: Registering new address record for 127.0.0.1 on lo.IPv4.
May 19 15:13:35 OasisMega1 avahi-daemon[954]: Server startup complete. Host name is OasisMega1.local. Local service cookie is 1025674960.
May 19 15:13:39 OasisMega1 avahi-daemon[954]: Got SIGHUP, reloading.
May 19 15:13:39 OasisMega1 avahi-daemon[954]: No service file found in /etc/avahi/services.
May 19 15:13:39 OasisMega1 NetworkManager[957]: <info>  [1779218019.8778] hostname: hostname: using hostnamed
May 19 15:13:39 OasisMega1 NetworkManager[957]: <info>  [1779218019.8778] hostname: static hostname changed from (none) to "OasisMega1"
May 19 15:13:39 OasisMega1 NetworkManager[957]: <info>  [1779218019.9126] dns-mgr[0x5b4832e212a0]: init: dns=systemd-resolved rc-manager=unmanaged (auto), plugin=systemd-resolved
May 19 15:13:39 OasisMega1 NetworkManager[957]: <info>  [1779218019.9390] manager[0x5b4832e43000]: rfkill: Wi-Fi hardware radio set enabled
May 19 15:13:39 OasisMega1 NetworkManager[957]: <info>  [1779218019.9391] manager[0x5b4832e43000]: rfkill: WWAN hardware radio set enabled
May 19 15:13:40 OasisMega1 NetworkManager[957]: <info>  [1779218020.1017] Loaded device plugin: NMBluezManager (/usr/lib/x86_64-linux-gnu/NetworkManager/1.36.6/libnm-device-plugin-bluetooth.so)
May 19 15:13:40 OasisMega1 NetworkManager[957]: <info>  [1779218020.1532] Loaded device plugin: NMWifiFactory (/usr/lib/x86_64-linux-gnu/NetworkManager/1.36.6/libnm-device-plugin-wifi.so)
May 19 15:13:40 OasisMega1 NetworkManager[957]: <info>  [1779218020.4388] Loaded device plugin: NMTeamFactory (/usr/lib/x86_64-linux-gnu/NetworkManager/1.36.6/libnm-device-plugin-team.so)
May 19 15:13:40 OasisMega1 dbus-daemon[956]: [system] Activating via systemd: service name='org.freedesktop.nm_dispatcher' unit='dbus-org.freedesktop.nm-dispatcher.service' requested by ':1.3' (uid=0 pid=957 comm="/usr/sbin/NetworkManager --no-daemon " label="unconfined")
May 19 15:13:40 OasisMega1 NetworkManager[957]: <info>  [1779218020.4404] Loaded device plugin: NMWwanFactory (/usr/lib/x86_64-linux-gnu/NetworkManager/1.36.6/libnm-device-plugin-wwan.so)
May 19 15:13:40 OasisMega1 NetworkManager[957]: <info>  [1779218020.5027] Loaded device plugin: NMAtmManager (/usr/lib/x86_64-linux-gnu/NetworkManager/1.36.6/libnm-device-plugin-adsl.so)
May 19 15:13:40 OasisMega1 NetworkManager[957]: <info>  [1779218020.5039] manager: rfkill: Wi-Fi enabled by radio killswitch; enabled by state file
May 19 15:13:40 OasisMega1 NetworkManager[957]: <info>  [1779218020.5042] manager: rfkill: WWAN enabled by radio killswitch; enabled by state file
May 19 15:13:40 OasisMega1 NetworkManager[957]: <info>  [1779218020.5044] manager: Networking is enabled by state file
May 19 15:13:40 OasisMega1 NetworkManager[957]: <info>  [1779218020.9815] settings: Loaded settings plugin: ifupdown ("/usr/lib/x86_64-linux-gnu/NetworkManager/1.36.6/libnm-settings-plugin-ifupdown.so")
May 19 15:13:40 OasisMega1 NetworkManager[957]: <info>  [1779218020.9816] settings: Loaded settings plugin: keyfile (internal)
May 19 15:13:40 OasisMega1 NetworkManager[957]: <info>  [1779218020.9816] ifupdown: management mode: unmanaged
May 19 15:13:40 OasisMega1 NetworkManager[957]: <info>  [1779218020.9817] ifupdown:       interface-parser: parsing file /etc/network/interfaces
May 19 15:13:40 OasisMega1 NetworkManager[957]: <info>  [1779218020.9817] ifupdown:       interface-parser: source line includes interfaces file(s) /etc/network/interfaces.d
May 19 15:13:40 OasisMega1 NetworkManager[957]: <info>  [1779218020.9818] ifupdown:       interface-parser: finished parsing file /etc/network/interfaces
May 19 15:13:40 OasisMega1 NetworkManager[957]: <info>  [1779218020.9821] ifupdown: guessed connection type (enp2s0) = 802-3-ethernet
May 19 15:13:41 OasisMega1 NetworkManager[957]: <info>  [1779218021.0154] dhcp-init: Using DHCP client 'internal'
May 19 15:13:41 OasisMega1 NetworkManager[957]: <info>  [1779218021.0155] device (lo): carrier: link connected
May 19 15:13:41 OasisMega1 NetworkManager[957]: <info>  [1779218021.0159] manager: (lo): new Generic device (/org/freedesktop/NetworkManager/Devices/1)
May 19 15:13:41 OasisMega1 NetworkManager[957]: <info>  [1779218021.0172] device (enp2s0): carrier: link connected
May 19 15:13:41 OasisMega1 NetworkManager[957]: <info>  [1779218021.0178] manager: (enp2s0): new Ethernet device (/org/freedesktop/NetworkManager/Devices/2)
May 19 15:13:41 OasisMega1 NetworkManager[957]: <info>  [1779218021.0241] manager: NetworkManager state is now CONNECTED_GLOBAL
May 19 15:13:41 OasisMega1 NetworkManager[957]: <info>  [1779218021.0277] manager: startup complete
May 19 15:13:42 OasisMega1 NetworkManager[957]: <info>  [1779218022.5674] modem-manager: ModemManager not available
May 19 15:13:42 OasisMega1 NetworkManager[957]: <info>  [1779218022.6046] modem-manager: ModemManager now available
May 19 15:13:51 OasisMega1 systemd[1]: NetworkManager-dispatcher.service: Deactivated successfully.
May 19 15:14:12 OasisMega1 NetworkManager[957]: <info>  [1779218052.8848] agent-manager: agent[5c3ea9d686d5f55e,:1.66/org.freedesktop.nm-applet/114]: agent registered
May 19 15:14:42 OasisMega1 NetworkManager[957]: <info>  [1779218082.6535] agent-manager: agent[210db125b3be2f95,:1.98/org.freedesktop.nm-applet/1000]: agent registered

Script: OS_Admin__Report_Syslog_Line_BootStart.sh

#!/bin/sh

log="/var/log/syslog"

lines=$( grep -n "Inserted module 'bfq'" ${log} |
	awk '{
		pos=index( $0, ":" ) ;
		beg=substr( $0, 1, pos-1 ) ;
		rem=substr( $0, pos+1 ) ;
		printf("%7d |%s\n", beg, rem ) ;
	}' )

latest=$( echo "${lines}" | tail -1 | awk '{ print $1 }' )
echo "latest = '${latest}'\n"

awk -v sline="${latest}" 'BEGIN{
	doPrint=0 ;
}{
	if( doPrint == 1 ){
		print $0 ;
	}else{
		if( NR == sline ){
			doPrint=1 ;
			printf("\n%s\n", $0 ) ;
		#}else{
		#	if ( NR % 100 == 0){
		#		printf(".") ;
		#	} ;
		} ;
	} ;
}' <${log} |
	awk -v sline="New relevant interface" 'BEGIN{
		doPrint=0 ;
		count=0 ;
	}{
		if( doPrint == 1 ){
			pos=index( $0, "avahi-daemon" ) ;
			if( pos >0 ){
				print $0 ;
			}else{
				pos=index( $0, "NetworkManager" ) ;
				if( pos > 0 ){
					print $0 ;
				}else{
					pos=index( $0, "systemd-resolved" ) ;
					if( pos > 0 ){
						print $0 ;
					} ;
				} ;
			} ;
			#count++ ;
			#if( count == 300 ){
			#	exit ;
			#} ;
		}else{
			if( index( $0, sline ) > 0 ){
				doPrint=1 ;
				printf("\n%s\n", $0 ) ;
				count++ ;
			} ;
		} ;
	}'


exit 0
exit 0
exit 0

ericmarceau · May 19, 2026, 10:38pm

Thank you, Eugene, but I did have that in the above list of commands attempted (all done attempted as root).

pavlos · May 19, 2026, 10:47pm

No, you have PCIe black x16, x1, x1, blue x16. The black or blue can be used with GPUs.

the last two are pci (the notch is way far to the right). In comparison, in the PCIe slots the notch is closer to the left. See image

So if you buy a card, the card would be x1 and it would fit between the black and blue.

pavlos · May 19, 2026, 10:57pm

it got an ip for that interface but Iater on, I cannot figure what happened.

Should you reboot your firewall to make sure DHCP is working ok?

about PCIe and PCI

All PCIe have the same 5 legs in the front so an x1 card can fit into an x1, x4, x8, even x16 but not the other way around. An x4 PCIe cannot fit into an x1 but can fit into an x4, x8, and x16.

PCI are very different, the notch is far way to the right and cannot fit into PCIe slots.

(I had a network hicup … now its ok.)

when you look at a PCIe card, the distance from begin to the notch is about 11mm or 1/2 inch. I think there are 11 gold plated contacts.

example: this is an x4, you see it is wider than x1 but they have the same distance till the notch (11 contacts).

IronRod · May 20, 2026, 2:10am

@ericmarceau I’m late to this party, but if this is still an issue, please share:

The exact message that is telling you " specifically “restart”, not “shutdown” then reboot".’
Output of both cat /etc/os-release and uname -r
Output of ifconfig when the NIC is recognized and when it is not.
Output of lspci both when the NIC is recognized and when it is not.
Output of ethtool -i enp2s0 (when it is working)

All of the commands you tried work at the network stack level. If the NIC isn’t even being recognized, it isn’t in the stack so those would not be effective. Let’s do the above to determine if the NIC itself is not coming online – which is what it sounds like.

ericmarceau · May 20, 2026, 9:34pm

My firewall router rarely presents issues. Also, my wife was actively using the internet from her computer, so I knew that it wasn’t the router.

ericmarceau · May 20, 2026, 9:43pm

That was just me being categorical as to how I rebooted. That was never a system-generated message.

As for the requested outputs:

# cat /etc/os-release
PRETTY_NAME="Ubuntu 22.04.5 LTS"
NAME="Ubuntu"
VERSION_ID="22.04"
VERSION="22.04.5 LTS (Jammy Jellyfish)"
VERSION_CODENAME=jammy
ID=ubuntu
ID_LIKE=debian
HOME_URL="https://www.ubuntu.com/"
SUPPORT_URL="https://help.ubuntu.com/"
BUG_REPORT_URL="https://bugs.launchpad.net/ubuntu/"
PRIVACY_POLICY_URL="https://www.ubuntu.com/legal/terms-and-policies/privacy-policy"
UBUNTU_CODENAME=jammy


# uname -r
6.8.0-45-generic


# ethtool -i enp2s0
driver: ATL1E
version: 6.8.0-45-generic
firmware-version: L1e
expansion-rom-version: 
bus-info: 0000:02:00.0
supports-statistics: no
supports-test: no
supports-eeprom-access: no
supports-register-dump: yes
supports-priv-flags: no


# ifconfig           (NOTE:  working)
enp2s0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 192.168.0.12  netmask 255.255.255.0  broadcast 192.168.0.255
        ether 00:26:18:8a:b5:7a  txqueuelen 1000  (Ethernet)
        RX packets 50491  bytes 55379505 (55.3 MB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 25151  bytes 6592635 (6.5 MB)
        TX errors 0  dropped 0 overruns 0  carrier 1  collisions 0


# lspci           (NOTE:  working)
00:00.0 Host bridge: Advanced Micro Devices, Inc. [AMD] RS780 Host Bridge
00:01.0 PCI bridge: Advanced Micro Devices, Inc. [AMD] RS780/RS880 PCI to PCI bridge (int gfx)
00:06.0 PCI bridge: Advanced Micro Devices, Inc. [AMD] RS780 PCI to PCI bridge (PCIE port 2)
        ***
02:00.0 Ethernet controller: Qualcomm Atheros AR8121/AR8113/AR8114 Gigabit or Fast Ethernet (rev b0)

Next time it happens, I can gather the responses to ifconfig & lspci, for comparison.

ericmarceau · May 20, 2026, 9:49pm

Pavlos, correct me if I am wrong, but your point is addressing the loss of the NIC some time after having had functional use of the NIC. Correct?

That is not my problem context. My problem is a condition immediately after boot, where the network has never come up at all!!! If that is the case, the GRUB fix you’ve suggested is not really applicable. Correct?

IronRod · May 20, 2026, 9:58pm

It’s always good to know the OS (Ubuntu 22.04.5 LTS) and the kernel (6.8) in use.

The successful ifconfig confirms that the driver loaded and is talking to the kernel; i.e., it connected to the network.

The ethtool tells us what driver is being used and what version. May be helpful later once we see what happens during a failure.

The successful lspci command identifies the adapter and confirms that it responded to the PCIe bus enumeration. It could still be a hardware failure but this is the place to start.

Let’s see what they show when you have the next failure.

pavlos · May 20, 2026, 9:59pm

maybe a bad rj45 cable?

I suggested rebooting the router so a fresh DHCP server starts and hopefully offers ip to all your computers.

If you boot your pc with a live distro, does it get wired?

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Erratic periodic event where there is no recognition of networking hardware at boot time

about PCIe and PCI

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