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Questions tagged [network-interface]

hardware (or its representation by software) that connects a computing device (host) to a computer network (net)

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How can I create a virtual ethernet interface on a machine without a physical adapter?

I have a Dell XPS 13 ultrabook which has a wifi nic, but no physical ethernet nic (wlan0, but no eth0). I need to create a virtual adapter for using Vagrant with NFS, but am finding that the typical ...
STW's user avatar
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67 votes
3 answers
111k views

iptables redirect outside requests to 127.0.0.1

I have a service running on 127.0.0.1 with port 2222. I need to forward all requests to 192.168.2.2:2222 (outside IP) only from subnet 192.168.1.0/24 to 127.0.0.1:2222. I'm trying to use this, but it'...
SimWhite's user avatar
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63 votes
4 answers
85k views

Bind unix program to specific network interface

Question: How do I launch a program while ensuring that its network access is bound via a specific network interface? Case: I want to access two distinct machines with the same IP (192.168.1.1), but ...
Skeen's user avatar
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49 votes
3 answers
82k views

How can I bridge two interfaces with ip/iproute2?

I know how to create a bridge using brctl, but I have been advised not to use this anymore, and to use iproute2 or ip instead(since brctl is deprecated presumably). Assuming this is good advice, how ...
Totem's user avatar
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44 votes
4 answers
14k views

What Linux process is responsible for responding to pings?

I have a Linux based process controller that occasionally locks up to the point where you can't ping it (i.e. I can ping it, then it becomes no longer pingable without any modifications to network ...
Izzo's user avatar
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43 votes
9 answers
149k views

Get Wi-Fi interface device names

Similar to a previous question about finding network device names, I would like to get a (reliable) list of device names but just for Wi-Fi devices. So that it looks like the following depending on ...
Matt Copperwaite's user avatar
32 votes
7 answers
222k views

CentOS 7 - Rename network interface without rebooting

I'm renaming network interfaces by modifying the files in /etc/sysconfig/network-scripts. eth0 -> nic0 eth1 -> nic1 The content of the network scripts looks like this, after modification: # cat /...
udondan's user avatar
  • 513
28 votes
2 answers
86k views

What is a hotplug event from the interface?

According to Debian Network setup document allow-hotplug <interface_name> stanza in /etc/network/interfaces file starts an interface when the kernel detects a hotplug event from the interface. ...
Martin's user avatar
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24 votes
6 answers
87k views

How can I make changes to the network routing metric permanently

I'm able change my network routing metrics with ifmetric, for example ifmetric enp0s3 1. Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface 0.0.0.0 ...
marathon's user avatar
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24 votes
7 answers
153k views

'iwlist' -> interface doesn't support scanning (Ubuntu LTS 10.04)

I am using Ubuntu 10.04 (LTS) on a Samsung N150+ netbook. I cannot scan wifi networks using iwlist and I would like to do so. Here is the output from some tests: alex@alex-laptop:~/Desktop/...
Vass's user avatar
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23 votes
3 answers
66k views

What does eno mean in network interface name 'eno16777736' for CentOS 7 or RHEL 7?

Under consistent network device naming scheme, what does 'eno' stand for in network interface name eno16777736 for CentOS 7 or RHEL 7?
Andy Huang's user avatar
23 votes
6 answers
55k views

How can I tell whether a network interface is physical (device) or virtual (alias)?

I have a small home router running OpenWrt (Kind of embedded Linux for routers). It has five Ethernet ports, one labeled WAN and four labeld LAN 1 to 4. It has the following Network Interfaces defined ...
Lumi's user avatar
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20 votes
3 answers
8k views

Why does Linux network traffic only go through eth0?

I got two NICs on the server side, eth0 ? 192.168.8.140 and eth1 ? 192.168.8.142. The client sends data to 192.168.8.142, and I expect iftop to show the traffic for eth1, but it does not. All networks ...
wener's user avatar
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19 votes
6 answers
74k views

How can I show the old eth0 names and also rename network interfaces in debian 9 stretch?

I would like to do 2 things: 1) Revert back the interfaces to the old classic name: eth0 instead of ens33. 2) Rename the interfaces in the way I want so that for example I can call interface eth0 ...
user3450548's user avatar
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19 votes
1 answer
121k views

proper syntax to delete default route for a particular interface?

summary: me@client:~$ sudo route del default ppp0 SIOCDELRT: No such process me@client:~$ sudo route del default dev ppp0 SIOCDELRT: No such process me@client:~$ sudo route del -net default dev ppp0 ...
TomRoche's user avatar
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18 votes
2 answers
21k views

How to determine the logical type of a linux network device

with logical I mean everything legal in the command ip link as in, for instance: ip link add link dum0 name dum0.200 type vlan protocol 802.1Q id 200 where the logical type would be "vlan". ...
JdeHaan's user avatar
  • 944
18 votes
3 answers
97k views

Change Mac Address permanently inside /etc/network/interfaces

QUESTION: How might I be able to specifically change the Mac Address of the enp3s0 and wlp2s0 interfaces through the /etc/network/interfaces file? What code would I have to include inside? I have ...
Webeng's user avatar
  • 423
17 votes
2 answers
55k views

Difference between ppp0 vs wwan0

I am Running Raspian on a RaspberryPi. When I plug in a GSM modem I see two interfaces - wwan0 & ppp0. wwan0 exists even when the GSM modem is plugged but not connected ppp0 exists only when ...
OneGuyInDc's user avatar
17 votes
2 answers
4k views

Network interface name has with at sign - what is it?

I am trying to hunt down information for why a network interface name would have an at sign, but there's too much noise in the results I am so far getting (I lack the correct terminology to search on) ...
tk-noodle's user avatar
  • 510
17 votes
2 answers
85k views

Device eth0 does not seem to be present, delaying initialization

I have cloned a fedora and now trying to configure network interfaces. Every time i am adding a new NIC, it starts with number eth3 (rather eth0). i have tried removing and modifying the 70-persistent-...
user2896215's user avatar
16 votes
7 answers
16k views

Naming convention standard for Ethernet and Wi-Fi interfaces on Linux machines

What is the naming convention standard for Ethernet and Wi-Fi interfaces on a Linux machine? We are developing a tool that should show only the Ethernet and Wi-Fi interfaces of the Linux machine and ...
Mohan Raj's user avatar
  • 161
16 votes
9 answers
104k views

No IP address on VMware running centos 7

I just now installed Cent OS 7 on my VMware 8 and I am not able to connect it to a network. I checked the VM network and its mapped to the physical NIC. The same setting work like charm on my CentOS ...
Atul's user avatar
  • 1,901
16 votes
2 answers
585 views

Ghost NTP server on Debian 8.6

So the university IT security team and I have been going around and around on this with no breaks... anyone have any thoughts on this: I recently set up a small file server for my lab running Debian ...
Tim Otchy's user avatar
  • 163
16 votes
2 answers
9k views

Allowed chars in Linux network interface names?

What is the allowed range of characters in Linux network interfaces names? I've searched around but did not find any definition or clarification. Are uppercase characters allowed? Are uppcase and ...
TheDiveO's user avatar
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15 votes
2 answers
77k views

How can we create multiple dummy interfaces on Linux?

To Create a Fake Ethernet dummy Interface On Linux we First initialize the dummy interface driver using the below command: /sbin/modprobe dummy. Then we Assign Ethernet Interface alias To Dummy Driver ...
Kushal's user avatar
  • 347
15 votes
5 answers
49k views

Remove secondary IP with NetworkManager / nmcli

I tried to assign a static IP to my Ubuntu 16.04 server using nmcli, which worked but it still has the original IP reserved as a "secondary" IP. I'm not sure how to get rid of it. 10.163.148.36 is ...
ravishi's user avatar
  • 305
15 votes
2 answers
261k views

Putting a network interface up/down from command line

In Xubuntu 14.04, I tried to use both ip and ifconfig to handle a network interface, but they gave the same result. $ sudo ifconfig wlan0 down $ sudo ip link set wlan0 down both correcly put down ...
BowPark's user avatar
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15 votes
1 answer
36k views

Understanding tun0 addresses

I have already done some searching and more or less understand what a tun0 interface does. I got the following from various sources, Packets sent by an operating system via a tun/tap device are ...
Masroor's user avatar
  • 295
15 votes
1 answer
23k views

Is it possible to get network interface index not via /sys?

So what I'm looking for is an interface index (or name) but the real one. if_nametoindex(3) and ioctl(2) don't seem to help me here. Now the only way I found how to do this is via /sys. Let me ...
UVV's user avatar
  • 3,068
14 votes
3 answers
41k views

changing the names of network interfaces, debian wheezy

I'm trying to set a name for an interface, "ethLan" instead of eth0. Doing so also ensures that the if's name will remain consistent at every reboot and kernel. I did find some articles in the ...
user's user avatar
  • 141
14 votes
1 answer
14k views

What exactly does it mean to set a networking interface up and down?

Say that we have the wireless interface wlan0. What does ip link set wlan0 up/down actually do? Power and poweroff the NIC? A lot of network configuration guides online nonchalantly describe it as ...
JoshuaRLi's user avatar
  • 253
14 votes
1 answer
134k views

How to set up an usb/ethernet interface in Linux?

me@me:~$ sudo /etc/init.d/networking restart [ ok ] Restarting networking (via systemctl): networking.service. me@me:~$ sudo service network-manager restart me@me:~$ sudo ifup eno1 Internet Systems ...
jenny's user avatar
  • 373
13 votes
2 answers
10k views

Possible to have both Wi-Fi and Ethernet connected to the same network?

I am running Arch Linux (on a Raspberry Pi 3) and tried to connect both the Ethernet and the Wi-Fi to the same network. route shows me the following: $ route Kernel IP routing table Destination ...
rityzmon's user avatar
  • 333
13 votes
1 answer
70k views

Interface doesn't go up with ip link set interface up

EDIT A posteriori, the problem was most likely related to the one described here. Original post Until yesterday, Internet was just fine and I connected without much problems. I then disabled the ...
glS's user avatar
  • 806
12 votes
2 answers
23k views

/etc/network/interfaces - difference between auto and allow-hotplug

I am running Debian 9.13. I tried to check what is the difference between auto eth1 and allow-hotplug eth1 in /etc/network/interfaces. I have eth1 networking interface connected via USB. I tried ...
Jędrzej Dudkiewicz's user avatar
12 votes
4 answers
62k views

Why are post-up commands in /etc/network/interfaces ran multiple times at boot?

Here is the content of /etc/network/interfaces: auto lo iface lo inet loopback auto eth0 iface eth0 inet dhcp post-up /etc/network/if-up.d/sshstart And sshstart is a script with the following in ...
TCZ8's user avatar
  • 1,069
12 votes
2 answers
48k views

Determine ethernet speed in RHEL 6

How to check whether eth0 has connection speed 10Mbit, 100Mbit or 1Gbit? I tried ethtool, but it says No data available. I also tried dmesg | grep -i duplex and it's empty. [root@dioptase ~]# lspci ...
basin's user avatar
  • 2,061
12 votes
1 answer
59k views

How to route between interfaces

I have the following setup: (192.168.4.1) Device A <-------> device B <-------> Device C (192.168.5.84) (192.168.5.1) (192....
Steven's user avatar
  • 151
12 votes
2 answers
17k views

The difference between ip link down and physical link absence

In Linux, is there any difference between after-ip link down-condition and real link absence (e.g. the switch's port burned down, or someone tripped over a wire). By difference I mean some signs in ...
red0ct's user avatar
  • 655
12 votes
1 answer
23k views

How can I list net work devices and ipv4 address on linux without ifconfig/ip command [duplicate]

I already figured out that on Linux I can list network devices (cd /proc/net/dev_snmp6/ && for device in *; do echo $device; done|sort) but how can I get the ipv4 address of the device? I ...
Mandragor's user avatar
  • 1,060
11 votes
5 answers
35k views

How many services are listening on the target system on all interfaces? (Not on localhost and IPv4 only)

I need to find out how many services are listening to my interfaces (ipv4 only, not localhost) $ ifconfig ens192: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500 inet 10.129.56.137 ...
YnSkn's user avatar
  • 343
11 votes
4 answers
10k views

RHEL: man page for interface configuration files

How to get the man page for ifcfg-$Interface files? Something like man 5 $Keyword for /etc/sysconfig/network-scripts/ifcfg-enp0s3. Is there not a man page? Is the keyword wrong? RHEL:~# cat /etc/os-...
user2964971's user avatar
11 votes
3 answers
22k views

Correct way to set dhcp in netplan

In some tutorials (Here and Here) about netplan dhcp4 appear in the following way: network: version: 2 renderer: networkd ethernets: enp2s0: dhcp4: no or dhcp4: yes But in netplan ...
acgbox's user avatar
  • 951
11 votes
1 answer
12k views

Why is my wlan device being renamed? [duplicate]

This is a selection from my dmesg: rtl8192cu 1-3:1.0 wlx10bef501e1cd: renamed from wlan0 wlx10bef501e1cd: authenticate with 90:94:e4:e7:99:cc wlx10bef501e1cd: send auth to 90:94:e4:e7:99:cc (try 1/3) ...
maja's user avatar
  • 285
10 votes
2 answers
80k views

systemd: How to unmask a service whose unit file is empty?

I tried to start wpa_supplicant.service, but I got the following error: Failed to start wpa_supplicant.service: Unit wpa_supplicant.service is masked. I tried unmasking it using systemctl unmask ...
user189141's user avatar
10 votes
3 answers
35k views

Making /dev/net/tun available to qemu?

I have created a tap device (tap0) which I would like to provide as a network interface to qemu. I created the device with the following command and attached it to a network bridge I set up: tunctl -...
Nathan Osman's user avatar
  • 6,240
10 votes
2 answers
9k views

Linux disables ethernet auto-negotiation on plugging-in the cable?

I recently noticed I am only getting 100Mbit/s of througput on my gigabit home network. When looking into it with ethtool I found my ArchLinux Box was using 100baseT/Half as link speed instead of ...
fallingcats's user avatar
10 votes
5 answers
16k views

Predictable Network Interface Names break vm migration

How do you reset /etc/networking/interfaces when using "predictable network interface names"? Versions of Ubuntu older than 15.10 use network adapter names like: eth0 eth1 eth2 Replacing a ...
spuder's user avatar
  • 18.1k
10 votes
3 answers
7k views

How to find out which process keeps tunnel interface(tun) up?

If I create a tun interface with ip tuntap add mode tun command and force it administratively up with ip link set dev tun1 up command, then the interface itself is always "physically" down: root@A58:~...
Martin's user avatar
  • 7,556
10 votes
1 answer
6k views

Where is wpa-conf documented?

I use wpa-conf in /etc/network/interfaces to make the WLAN interface automatically connect to the AP: # This file describes the network interfaces available on your system # and how to activate them. ...
viuser's user avatar
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