Questions tagged [ifconfig]

ifconfig is a system administration utility in Unix-like operating systems to configure, control, and query TCP/IP network interface parameters from a command line interface (CLI) or in system configuration scripts.

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Debian 10 backward compatibility with eth0

Noticed when upgrading to Debian 10 (Buster) that the public eth0 network interface is now called ens5 on AWS EC2. Is there a way to create a symbolic link or similar so that legacy applications that ...
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huge difference in RX bytes vs TX bytes (ifconfig) on Syslog-NG server

we have a syslog-ng server acting as an intermediary logger. the server receives data from all devices on the network (from many different sources, on both UDP & TCP ports), filters them a bit, ...
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commands to make ethernet interfaces up down using ip command

I was using following commands to up the devices # ifconfig p1p1:1 10.250.0.0 netmask 255.255.0.0 up # ifconfig p1p1:2 10.251.0.0 netmask 255.255.0.0 up # ifconfig p1p1:3 10.252.0.0 netmask 255.255.0....
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How can I get ubuntu network interface stats in the terabyte range?

When I query my server's network interface stats using either ifconfig or ip -s they're limited to 999GB and then roll over to 0GB, starting again. Is it possible to change the configuration somehow ...
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Ubuntu 18.04 keeps creating virtual interface ens160:0, how to prevent?

I am running a Pi-hole server on Ubuntu 18.04 that for some reason keeps making a virtual interface ens160:0 user@pihole2:/etc$ ip a 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state ...
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Virtual IP on MacOS does not receive any TCP data, why? (with details)

$ ifconfig en0 en0: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 1500 options=400<CHANNEL_IO> ether a4:83:e7:d0:e7:a5 inet 10.0.0.134 netmask 0xffffff00 ...
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netplan secondary IP address max limit [duplicate]

We need 64K secondary IPs on the linux eth0 interface. The goal is to be able to program the ip addresses in less than 10 seconds. Configuring manually one at a time takes 10 mins or more. netplan ...
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355 views

NetworkManager adding extra default gateway

Using NetworkManager, I am trying to setup multiple interfaces on different VLANs; the primary interface, em1, is used on a development VLAN; the secondary interface is on a dedicated iSCSI VLAN. I am ...
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119 views

SSH Reverse Tunnel: Bind Address is ignored

I'm trying to configure a server in one site to act as a proxy for several servers in another site using SSH. The server has one physical interface in its local network: eth0 10.1.1.10 This server ...
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152 views

Dante SOCKS server with two external interfaces (e.g. Wired Ethernet and Wi-Fi)

I want Dante to transparently choose between either of the two interfaces enp4s0 (Wired Ethernet) and wlp3s0 (Wi-Fi) regardless of their status (up or down). That is when wired, it should choose ...
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Route Table Multiple Subnet Entries?

So just as a bit of context, this is for a VM running that does call processing. So I was looking at the route table on the VM, and noticed that it has this: 12.12.12.64/28 dev bond15 proto kernel ...
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How to go back default settings of eth0

When my system starts, eth0 was not assigned with any of the IP addresses. Its looks like below root@etn-cgtqmx6:~# ifconfig eth0 Link encap:Ethernet HWaddr xx:xx:xx:xx:xx:xx UP ...
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Why is the mac address that appears on my computer the same?

I use the 2 ethernet interface on the my system board, eth0 / eth1(usb to ethernet) like the followings. root@E3-RDP:~# ifconfig eth0 Link encap:Ethernet HWaddr ae:a1:99:48:86:79 inet addr:10.10.0....
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ifconfig interface down vs unplugging cable

What's the difference between ifconfig eth0 down and physically unplugging eth0 cable? Do they mean the same thing to an application? Edit: I have an application that uses a specific interface let's ...
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3k views

openvpn - ifconfig parameter

What does ifconfig parameter in openvpn configuration file mean? Here is an example file: dev tun0 proto udp comp-lzo port 5073 remote 172.16.23.73 5073 ifconfig 172.17.3.41 172.17.3.43
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179 views

Netmask for point to point ip address?

In a point to point tunnel, I was able to have the same IP twice. It looks like a bug, I think that might be related to some internal representation of the netmask. It can be reproduced with the steps ...
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79 views

Same IP twice in the same interface

I'm trying to find a bug in a program and I was wondering if it is possible to have the same IP twice in a network interface. For example, have network interface eth1 with ip 192.168.56.174 twice. I ...
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Network interface statistics: tx_dropped value always 0

I am writing a program that collects and displays network interface metrics located in the /sys/class/net/ folder. When I was reading about the meaning of rx_dropped value, I came to the conclusion ...
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Ubuntu secondary IP drops out after a few hours

I'm running Ubuntu 18.10 on a VPS. Ever since upgrading (I'm pretty sure) from 16.04, my secondary IP address just stops receiving traffic after it's been up for a few hours. I'll have two pings ...
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Ubuntu SSH connection hangs when I run ifconfig with IPv6 enabled

I've been playing around with IPv6 and setup a DigitalOcean droplet. The only difference between now and before is that I told it to setup IPv6. More often than not, when I run ifconfig the SSH ...
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ifconfig shows UP while ip link shows DOWN

I am looking at the state of an interface on a Linux system. When I use the ifconfig command it shows that the link is UP. master $ ifconfig docker0 docker0 Link encap:Ethernet HWaddr 02:42:b9:25:...
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377 views

Ubuntu: Multiple interfaces, one lan only

I have 2 interfaces: wlan0: Connected to normal network with DHCP (has internet) eth0: Connected to LAN only. Used for PXE boot and NFS The network-manager service is not installed on this machine. ...
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1answer
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iptables - bridge / routing between two independent LANs (and router)

I can't find a solution in a network like in the drawing below. I need to be able to open admin page of router 2 on LAN2 from a pc in a LAN1, w/o routing throught Internet. I have a "bridge" PC with ...
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Debian ignores static IP assignment

My etc/network/interfaces file originally only included info regarding lo: # The loopback network interface auto lo iface lo inet loopback ifconfig shows me that eth0 is getting an IP from DHCP. ...
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Meaning of rx_fcs_errors

On my server I do see RX frame errors in ifconfig: eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500 ether d0:50:99:30:f6:81 txqueuelen 1000 (Ethernet) RX packets ...
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Linux virtual network - no internet connection

I created virtual network, however I can't connect to the internet with it. sudo ip link add name br0 type veth peer name br1 sudo ip link set br0 up I am checking it with: curl --interface br0 ...
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328 views

Routing traffic between two subnets

I am connecting some number of embedded linux devices to a main LAN using a DHCP server and routing tables. On the main LAN (192.168.1.0/24) I have a PC connected and the first embedded linux device. ...
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552 views

Ubuntu 16.04 VPS dropping massive amount of RX Packets

Having networking issues with a Ubuntu 16.04 VPS, causing extremely slow speeds (we're talking about 100kbps). Running ifconfig is showing over a million dropped RX packets from eth0 (no errors) and I ...
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746 views

Why can't I ping 127.0.0.1 from some network interfaces?

I'm on OS Sierra. This is (part of) what I get on ifconfig ... en0: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 1500 ether 98:01:a7:b4:91:63 inet6 fe80::4e:52ae:9fa8:...
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Can I change names of network interfaces arbitrary?

I have installed OpenWRT on VirtualBox. There are four interfaces: br-lan eth0 eth1 lo Why do they call that way? Are they variables? Can I name them arbitrary? foo-bar xyz0 xyz1 bo Like so: ...
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390 views

Display only the network interfaces which has the ip address using ip command

I use ip a to get the IP address of my machine. Sometimes, it is getting difficult to identify when I have 20+ network interfaces. Is there a way to display only network interfaces which has IP? The ...
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47 views

Can't ping 253.100.156.93 from Linux

At a remote location, there is a chinese ethernet enabled POS printer. It somehow garbled it's configuration, and its self-test now says that its IP address is 253.100.156.93, (which is inside a IANA ...
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1answer
898 views

What is this virtual interface? And how can I remove it?

I am using RHEL 7.4 and had both a virbr0 and virbr1. I want to remove them both. I was able to remove virbr0 by stopping and disabling the default virtual kvm. libvirtd isn't running, yet I still ...
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764 views

ip command equivalent to `ifconfig lo x.x.x.x up`

I am trying to set bind loopback to an IP address with ip link set lo 10.254.254.254 up but keep getting the error Error: either "dev" is duplicate, or "10.254.254.254" is a garbage. I googled the ...
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ifconfig displays public IP address

I've logged via ssh to remote host. When I type ifconfig output contains: ens160: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500 inet 106.120.101.39 netmask 255.255.255.128 ...
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474 views

linux fine tuning after setting the MTU to jumbo frame

We want to set the MTU to 9000 bytes on our Linux machines (distribution is Redhat 7) In this case, how would I tune the memory page size according to MTU size of 9000 bytes? Also, what are the ...
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845 views

ifconfig up does not execute from cron

I'm attempting to combine Scott Lowe's guide to creating a namespace with this answer on forwarding traffic between two interfaces. I have this script that runs on each reboot using the cron @reboot ...
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1answer
2k views

How to permanently remove lo:0 interface?

I have two ubuntu 16.04 servers here that were upgraded from 10.04 and are now virtual machines but used to be running on physical hardware using two bonded ethernet ports. The bonding configuration ...
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2answers
509 views

How to access guest virtual with CentOS using additional ip?

I have a dedicated server in Hetzner. In which I have installed CentOS 7.4, inside it I have KVM with another CentOS 7.4. I have requested an additional ip from Hetzner that has a Mac separated for ...
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493 views

ovh's fail-over ip as a gateway

I own one of OVH's VPS instances. It's located in France. I've deployed an application which connects to a service located in Poland. The problem is the service rejects any connections from foreign ...
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1answer
823 views

Only route WLAN over VPN

I am trying to set up my RP3 in such a way that WiFi connections are routed over an L2TP VPN. I've got the VPN working and with the following settings all traffic is routed over the VPN connection (...
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Can only bring up one interface at a time

I took a look at the most relevant question, and am a step further but am not sure where to go from here. I am currently trying to connect two ethernet interfaces but am having trouble establishing a ...
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996 views

OpenWRT always shows only one network interface (`lo`), although there are many in a config

I’m running OpenWRT in VMWare Workstation 12 Player on Windows 10 64bit. When I run ifconfig in my OpenWRT, I always get only one network interface, lo. Never more: Although there are several ...
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728 views

Secondary interface does not receive UDP traffic for *:PORT application

I have dedicated server in OVH. Recently I bought additional IP for my server. Default/main IP is on eth0 interface, both TCP and UDP works fine, no problems. I followed OVH tutorial how to add ...
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ip route add: RTNETLINK answers: Network is down

I'm quite new to networking and I really can't figure this out. I am trying to add a static route so that all traffic to aa.aa.aa.aa goes through eth0:0 interface root@LSW-199:~# ifconfig eth0 ...
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What is the local routing table used for?

I am trying to understand what is the local routing table. If I add a random address in it with the following command: sudo ip route add to local <any-ip-address> dev <network interface> ...
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4answers
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Running a bash script as root on boot

i have a script that calculate an ip address (using gateway address) than change, the script work when i launch it manually with sudo sudo ./changework.sh i want this script to run during bootup ...
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Server responds to an IP address which is not assigned

I have a rather out-of-date debian server, which has only one assigned IP address - 10.1.1.2 - this address is assigned manually in /etc/network/interfaces However, I just discovered that the server ...
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2answers
120 views

Accidentally changed ip on external NIC and can't get back into server. How can i reconnect

I was SSH'd into a server today and I changed the ip of my externally facing NIC and now I can't SSH back to the server. I ran the following command: ifconfig eno1 <ip> netmask 255.255.255.0 ...
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FreeBSD 11 not showing RX,TX packets and counts

I am having a FreeBSD 11 system in which I get the following output for ifconfig command # ifconfig lo0: flags=8049<UP,LOOPBACK,RUNNING,MULTICAST> metric 0 mtu 16384 options=600003<...

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