Network issue. Ifup says unknown interface
84,086
Solution 1
ifup
and ifdown
are used to set up interfaces listed in /etc/network/interfaces
. enp0s3
isn't described in this file, so it's absolutely expected that ifup
and ifdown don't know what to do with it. Add some lines such as
iface enp0s3 inet dhcp
And you'll see that it will work much better.
Solution 2
I used the following commands:
cat /proc/net/dev
ls /sys/class/net
ip link show
ifconfig
sudo ifconfig [interface-name] down / up
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Author by
searcot jabali
Updated on September 18, 2022Comments
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searcot jabali over 1 year
This is the output of ifconfig
# ifconfig enp0s3 Link encap:Ethernet HWaddr 08:00:27:ef:b6:e6 inet addr:192.168.2.3 Bcast:192.168.2.255 Mask:255.255.255.0 inet6 addr: fe80::cf19:776a:4d5c:36e0/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:713069 errors:0 dropped:0 overruns:0 frame:0 TX packets:6767 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:45869812 (45.8 MB) TX bytes:667164 (667.1 KB) lo Link encap:Local Loopback inet addr:127.0.0.1 Mask:255.0.0.0 inet6 addr: ::1/128 Scope:Host UP LOOPBACK RUNNING MTU:65536 Metric:1 RX packets:1108 errors:0 dropped:0 overruns:0 frame:0 TX packets:1108 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:86846 (86.8 KB) TX bytes:86846 (86.8 KB)
When I do
# ifdown enp0s3
It says Unknown interface enp0s3
The network is fine and works without any issues. Its just the command that does not work
Ubuntu 16.04 (Xenial)
Below is the output of
ip a s
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127.0.0.1/8 scope host lo valid_lft forever preferred_lft forever inet6 ::1/128 scope host valid_lft forever preferred_lft forever 2: enp0s3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000 link/ether 08:00:27:ef:b6:e6 brd ff:ff:ff:ff:ff:ff inet 192.168.2.7/24 brd 192.168.2.255 scope global enp0s3 valid_lft forever preferred_lft forever inet6 fe80::cf19:776a:4d5c:36e0/64 scope link valid_lft forever preferred_lft forever
Below is my /etc/network/interfaces
# interfaces(5) file used by ifup(8) and ifdown(8) auto lo iface lo inet loopback
Output of nmcli conn sh
Wired connection 1 42d740b1-21c3-3b7c-8b9e-5922fe8a6380 802-3-ethernet enp0s3
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Admin over 6 yearsHave you tried
ip link set dev enp0s3 up
Doesenp0s3
match your configuration in/etc/network/interfaces
? -
Admin over 6 yearsWhat is the output of ip a s ?
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Admin over 6 years@bgtvfr : The output is too long to paste in one go. So Multi comment
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127.0.0.1/8 scope host lo valid_lft forever preferred_lft forever inet6 ::1/128 scope host valid_lft forever preferred_lft forever
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Admin over 6 years@bgtvfr: Part 2 of output
2: enp0s3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000 link/ether 08:00:27:ef:b6:e6 brd ff:ff:ff:ff:ff:ff inet 192.168.2.7/24 brd 192.168.2.255 scope global enp0s3 valid_lft forever preferred_lft forever inet6 fe80::cf19:776a:4d5c:36e0/64 scope link valid_lft forever preferred_lft forever
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Admin over 6 years@val0x00ff: Weirdly my interfaces file has only this in it
# interfaces(5) file used by ifup(8) and ifdown(8) auto lo iface lo inet loopback
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Admin over 6 years@searcotjabali please update your question with these additional details. Comments read very hard! Your network is controlled by
NetworkManager
and you can usenmcli conn sh
to see the connections. Alsoifconfig
is obsoleted byip
which is a command fromiproute2
tools. Useip
instead as I stated in my first comment -
Admin over 6 years@val0x00ff: Sorry. I am kinda used to ifconfig. I updated my question with the details. Thanks :-)
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Admin over 6 years@searcotjabali please see
man nmcli
how to control your interfaces. You are usingNetworkManager
which controls your interfaces. The man page has many examples that show you how to bring an interface up or down.
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Hellreaver almost 3 yearsSorry, can you explain what's done here? Are you just defining the interface enp0s3 as an internet+dhcp interface?
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wazoox almost 3 years@Hellreaver Yes. Notice that the interface must already exist in the "ip" or "ifconfig" output. For the detailed syntax of /etc/network/interfaces please Read The Fine Manual: "man interfaces" or see manpages.org/etc-network-interfaces/5