how do I set up a trunked ethernet interface?

My 01-netcfg.yaml looks like this:

# This file describes the network interfaces available on your system # For more information, see netplan(5). network:   version: 2   renderer: networkd   ethernets:     ens1f0np0:       dhcp4: no       addresses: [ ]       gateway4:       nameservers:           search: [ ]           addresses:               # - ""               - ""     ens2f0np0:       dhcp4: no       addresses: [ ]       #      gateway4:       nameservers:           search: [ ]           addresses:            # - ""               - "" 

I’d like to add a vlan to ens1f0np0, how is this done? OS Details:


Ethernet Adapter Detected but the ethernet cable isn’t

I recently bought a usb ethernet adapter as my laptop has no ethernet ports. The laptop detects the adapter, the driver is installed, but the ethenet cable isn’t detected. The cable works fine for other laptops. the results of ethtool enx00e001103008 shows:

Settings for enx00e001103008:     Supported ports: [ TP MII ]     Supported link modes:   10baseT/Half 10baseT/Full                              100baseT/Half 100baseT/Full      Supported pause frame use: No     Supports auto-negotiation: Yes     Supported FEC modes: Not reported     Advertised link modes:  Not reported     Advertised pause frame use: No     Advertised auto-negotiation: No     Advertised FEC modes: Not reported     Speed: 100Mb/s     Duplex: Half     Port: MII     PHYAD: 0     Transceiver: internal     Auto-negotiation: off     Current message level: 0x00000007 (7)                    drv probe link     Link detected: no 

The link detected always shows ‘no’.

The output for lshw -c network is:

*-network:0        description: Ethernet interface        physical id: 2        logical name: enx00e001103008        serial: 00:e0:01:10:30:08        size: 100Mbit/s        capacity: 100Mbit/s        capabilities: ethernet physical tp mii 10bt 10bt-fd 100bt 100bt-fd autonegotiation        configuration: autonegotiation=off broadcast=yes driver=dm9601 driverversion=22-Aug-2005 duplex=half firmware=Davicom DM96xx USB 10/100 Ether link=no multicast=yes port=MII speed=100Mbit/s 

Stop ethernet from automatically reconnecting

I have a dual Ethernet connection setup on my computer running Ubuntu 18 in a VM from virtual box. I need to disconnect one or the other occasionally because of lack of routing in some applications. Problem is that whenever I disconnect Eth0, the OS will automatically create a connection, “eth0.” If I delete or disconnect from “eth0,” the OS will reconnect.

I am thinking this is part of autoethernet but not sure how to stop it.

Ubuntu 19.04 won’t connect via Ethernet

I just built a custom PC with Windows 10 installed on one SSD, and Ubuntu 19.04 on another SSD. My Windows OS connects to the internet just fine via Ethernet, but Ubuntu absolutely refuses to connect. This is a fresh install of 19.04.

I’ve read a ton of forums online, both on this site and others, and tried many solutions, including editing the /etc/network/interfaces file, the /etc/NetworkManager/NetworkManager.conf file, messing around with the resolv.conf and related files, changing ifupdown settings, and absolutely nothing works. I installed the r8168driver using a flash drive in the hopes it would work, but nothing happens. I bypassed my router and connected Ethernet cable directly from modem to computer: nothing. For some reason, Ubuntu will not receive any DNS information. It’s not a faulty Ethernet cable since Windows works just fine. I’m at my wit’s end about what to do.

For information, I’m using:

  • Ubuntu 19.04
  • AMD Ryzen 9 processor
  • Asus ROG Crosshair VIII Hero (Wi-Fi) motherboard

I’m no stranger to Linux/Ubuntu, having used it for years. Also, my Ubuntu install is separate from my Windows install, and I’m very comfortable in the command line, so I don’t mind messing around with files or settings that might have adverse effects, as I have another OS to fall back on if something gets corrupted. Could anyone provide any insight?

No ethernet after 18.04.2 to 18.04.3 upgrade (LTS)

I upgraded my desktop from Mint 17 to Ubuntu 18.04.2 this past March (KDE desktop).

Today the KDE5 clipboard randomly stopped working (again), so I decided to do all the package upgrades that had piled up and reboot, not realizing 18.04.3 had come out.

I didn’t change any configuration, and now even though every tool confirms my ethernet config is unchanged, the machine is not connected. I was able to connect by booting from the 18.04 live CD, so it’s not a hardware issue.

I wasn’t aware that netplan is a thing, so I tried the answer here which didn’t work.

The corresponding port light on my switch is blinking, but the router doesn’t show this machine in its client list. Restarting the networking and network-manager services accomplishes nothing.

$   ifconfig -a enp5s0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500         inet  netmask  broadcast         inet6 fe80::ecb1:ac3e:c98b:504b  prefixlen 64  scopeid 0x20<link>         ether fc:aa:14:21:71:1e  txqueuelen 1000  (Ethernet)         RX packets 0  bytes 0 (0.0 B)         RX errors 0  dropped 0  overruns 0  frame 0         TX packets 689  bytes 50531 (50.5 KB)         TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0  lo: flags=73<UP,LOOPBACK,RUNNING>  mtu 65536         inet  netmask         inet6 ::1  prefixlen 128  scopeid 0x10<host>         loop  txqueuelen 1000  (Local Loopback)         RX packets 1695  bytes 145459 (145.4 KB)         RX errors 0  dropped 0  overruns 0  frame 0         TX packets 1695  bytes 145459 (145.4 KB)         TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0  
$   lshw -C network   *-network        description: Ethernet interface        product: RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller        vendor: Realtek Semiconductor Co., Ltd.        physical id: 0        bus info: pci@0000:05:00.0        logical name: enp5s0        version: 06        serial: fc:aa:14:21:71:1e        size: 1Gbit/s        capacity: 1Gbit/s        width: 64 bits        clock: 33MHz        capabilities: pm msi pciexpress msix vpd bus_master cap_list ethernet physical tp mii 10bt 10bt-fd 100bt 100bt-fd 1000bt 1000bt-fd autonegotiation        configuration: autonegotiation=off broadcast=yes driver=r8169 duplex=full firmware=rtl8168e-3_0.0.4 03/27/12 ip= latency=0 link=yes multicast=yes port=MII speed=1Gbit/s        resources: irq:16 ioport:b000(size=256) memory:fe600000-fe600fff memory:d0300000-d0303fff 

I noticed these lines in dmesg:

[   27.396723] systemd[1]: Found ordering cycle on networking-routes.service/start [   27.396726] systemd[1]: Found dependency on [   27.396728] systemd[1]: Job networking-routes.service/start deleted to break ordering cycle starting with 


[   51.189046] RTL8211E Gigabit Ethernet r8169-500:00: attached PHY driver [RTL8211E Gigabit Ethernet] (mii_bus:phy_addr=r8169-500:00, irq=IGNORE) [   51.189046] RTL8211E Gigabit Ethernet r8169-500:00: attached PHY driver [RTL8211E Gigabit Ethernet] (mii_bus:phy_addr=r8169-500:00, irq=IGNORE) [   51.406971] r8169 0000:05:00.0 enp5s0: Link is Down [   52.952958] r8169 0000:05:00.0 enp5s0: Link is Up - 100Mbps/Full - flow control rx/tx [   52.952975] IPv6: ADDRCONF(NETDEV_CHANGE): enp5s0: link becomes ready [   53.468053] kauditd_printk_skb: 14 callbacks suppressed 

Bionic: Why does my wired ethernet only connect after waking from suspend?

Does anyone know why my wired connection only connects after I have woken my laptop from suspend?

If I restart my pc it refuses to connect via cable but connects via wifi without any problem. If I then suspend my machine and then wake it up it then connects via the ethernet cable automatically.

Any ideas?

Wired Network refuses to connect (Ethernet / Ubuntu 18.04)

Getting the error message “Activation of network connection failed”

Running lspci -nnk | grep 0200 -A3 gave this answer :

07:00.0 Ethernet controller [0200]: Realtek Semiconductor Co., Ltd. RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller [10ec:8168] (rev 03)

Subsystem: Fujitsu Technology Solutions RTL8111/8168/8411 OCI Express Gigabit Ethernet Controller [1734:118d]

Kernel driver in us: r8169

Kernel modules: r8169

What is the average time for a node to transmit on the shared medium for Ethernet? (IEEE 802.3)

Suppose a shared ethernet link L, in which for nodes T1-T4 and a router R are connected:

--------------------------- R    |     |     |     |   T1    T2    T3    T4 

L has bit-rate C=100 Mbps, and propagation delay is PROP = 10 msec. Every node transmits packet with probability Pb = 10%. The mean packet length is P(length)=100 KBytes

Note that ethernet uses CSMA/CA

What is the average time for a node to transmit on the shared medium?

How to Configure Ubuntu to Access Internet only with Wifi Ignoring Wire Connection (Ethernet)


  • the Wifi connection works perfectly with the DHCP of the router. Only with this connection, I can navigate the web.
  • the wire connection is necessary for me to be connected directly with an embedded system. In the middle there is a Switch and the only things I do is to set up the address IP of both (laptop and embedded system). The systems speak perfectly using ssh etc. No problem here.
  • OS Xubuntu 16.04 on my laptop and a Linaro on the embedded.

Problem: When I am connected to the system with the ethernet connection, it is impossible for me to navigate on the web. I guess it is because the laptop try to access using the ethernet connection. Of course, the ethernet connection goes only to the embedded system.

Question: Can I use the ethernet only for the system and the wifi to continue to navigate the web pages? How can I do that?

Connecting two ethernet ports with a bridge kills local network

I’ve just finished rebuilding my NAS, now using an Intel-based SBC with two Realtek ethernet ports (Odroid H2 for those interested). Everything worked fine so far, up until I tried to use both ethernet ports in a bridge to maximize local network bandwidth (this NAS will be used to stream multiple 4K streams locally).

Setup of hardware is simple: the H2, with a 256GB NVMe SSD in the M.2 slot, two HDDs connected to the two SATA ports, and the two ethernet ports are slotted on my router’s (HyperOptic’s modem+router combo Tilgin HG2381) first two LAN ports.

Software-wise it’s also simple: regular Ubuntu Server 19.04 install on the SSD, where I store my cloud stuff, Docker’s stuff (images, config folders), etc.; and the two HDDs are in a RAID0 array with a single XFS partition for storage of media. Data loss is not a danger, as I do not care much about the content on the HDDs, and the docker configs (the irreplaceable bit) is backed up daily to Google Drive.

I’ve purged cloud-init from the system, and set the netplan renderer to NetworkManager, so that I could use Cockpit’s web interface for management of all. Extra networking software installed is zerotier, which I found to be the most simple to set up and manage.

The two separate network interfaces work well, but the device gets two separate IPs. I wish to treat this connection as a single interface with load balancing, so I’ve created a bridge out of the two and set a static IPv4 address to it. The moment this network configuration is activated, the whole local network dies – WiFi, internet access, local network access, everything. While I do enjoy the discovery of this kill switch, I’d really like to fix it.

The current NetworkManager configs:

Wired connection 1:

[connection] id=Wired connection 1 uuid=8d403f31-b593-38b7-a177-62d26ac8604c type=ethernet autoconnect-priority=-999 master=bridge0 permissions= slave-type=bridge timestamp=1565379408  [ethernet] mac-address=00:1E:06:45:06:C1 mac-address-blacklist= 

Wired connection 2:

[connection] id=Wired connection 2 uuid=a440422a-941f-32c0-8863-5b35e3a9cd12 type=ethernet autoconnect-priority=-999 master=bridge0 permissions= slave-type=bridge timestamp=1565379408  [ethernet] mac-address=00:1E:06:45:06:C2 mac-address-blacklist= 


[connection] id=bridge0 uuid=c60701c0-12f2-4624-a6d0-4f0ba327445f type=bridge autoconnect-slaves=1 interface-name=bridge0 permissions= timestamp=1565379708  [bridge] stp=false  [ipv4] address1=, dns=;; dns-search= method=manual  [ipv6] addr-gen-mode=stable-privacy dns-search= method=auto 

At first look I do not see any issue here, however I’m nowhere near even a NetworkManager adept (I’m still familiarizing myself with it, after almost exclusively using /etc/network/interfaces – not many embedded devices have fully blown fancy-pants network management systems, even routers!). Is there something wrong with my network config, or is it the router not handling a bridged interface well?