Questions tagged [networking]

Managing and using network connectivity on a Ubuntu system

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774 votes
22 answers
1.6m views

Command for determining my public IP?

If I check with google, I can see my public IP. Is there something on the Ubuntu command-line which will yield me the same answer?
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560 votes
23 answers
1.1m views

How to display network traffic in the terminal?

how to display the actual network traffic (wireless) in a terminal? Additionally: Is it possible to add this info to the chart of top?
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485 votes
8 answers
836k views

How to know what program is listening on a given port?

I suspect a program is listening on port 8000 on my machine. When I run the following command, I get this error: > python -m SimpleHTTPServer # Lots of python error socket.error: [Errno 98] ...
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386 votes
43 answers
1.7m views

Installing Broadcom Wireless Drivers

I'm having serious problems installing the Broadcom drivers for Ubuntu. It worked perfectly on my previous version, but now, it is impossible. What are the steps to install Broadcom wireless drivers ...
296 votes
18 answers
1.8m views

How to restart the networking service?

I tried to use sudo service networking restart and sudo /etc/init.d/network restart but they both crash the window manager and I can no longer use my keyboard for input into X. when I use the /...
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  • 4,362
294 votes
9 answers
1.2m views

How do I find my internal ip address?

I have Ubuntu server 12.04 installed, so I have no GUI. When I do the command ifconfig, I cannot find my internal IP address. It says inet addr: 127.0.0.1. Here is the output of ifconfig -a: eth0 ...
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272 votes
6 answers
197k views

How do I find out which process is eating up my bandwidth?

I think I'm being the victim of a bug here. Sometimes while I'm working (I still don't know why), my network traffic goes up to 200 KB/s and stays that way, even tough I'm not doing anything internet-...
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  • 9,516
263 votes
15 answers
474k views

How do I clear the DNS cache?

I just updated the DNS record (ns1, ns2, ns3.myhostingcompany.com) for a site I've got hosted, but I still get the domain registrar parking page. I'd like to see if the problem is Ubuntu's cached DNS ...
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  • 3,269
221 votes
10 answers
605k views

How can I see what ports are open on my machine?

I would like to see what ports are open on my machine, e.g. what ports my machine is listening on. E.g. port 80 if I have installed a web server, and so on. Is there any command for this?
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  • 7,487
219 votes
8 answers
298k views

How do you test the network speed between two boxes?

I have a gigabit network set up in my house and a few Ubuntu based boxes. Out of complete curiosity I would like to check the speed between the two boxes. I am not having any problems with speed or ...
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  • 4,715
181 votes
1 answer
358k views

What is the loopback device and how do I use it?

What are loopback and localhost? Why do they exist, what are they used for, and how would I use them?
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163 votes
12 answers
139k views

Wifi doesn't work after suspend after 16.04 upgrade

This particular version of the "doesn't work after suspend" came after upgrading to 16.04. It seems that the upgrade includes a Wicd applet (added to Metacity Classic Gnome task bar alongside regular ...
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  • 2,075
155 votes
3 answers
202k views

How do I install dig?

How do I install dig (the DNS lookup tool)? I can't figure out what the package name is.
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  • 5,715
155 votes
6 answers
48k views

Best way to cache apt downloads on a LAN?

I have multiple Ubuntu machines at home and a pretty slow internet connection, and sometimes multiple machines need to be updated at once (especially during new Ubuntu releases.) Is there a way where ...
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  • 2,013
150 votes
8 answers
141k views

How do I SSH to machine A via B in one command?

I want to access a computer, say machine A which is based in my university's network. However, this computer is only accessible via the internal network of the university, so I can not use SSH to this ...
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  • 1,642
146 votes
5 answers
338k views

What is the equivalent of the "tracert" DOS command?

tracert is a command in MS-DOS command prompt to trace the route to an IP Address. Is there any command in the Gnome Terminal equivalent to this?
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  • 5,246
138 votes
4 answers
138k views

Network service discovery disabled: What does this mean for me?

Every time at boot I get a message “Network service discovery disabled. Your current network has a .local domain, which is not recommended and incompatible with the Avahi network service discovery. ...
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134 votes
3 answers
206k views

Why is my network interface named enp0s25 instead of eth0?

A lot of my scripts stopped working after installing Ubuntu 15.10 and I have trouble remembering this new name as I was used to ethx and wlanx for years. Is there a reason for this change? Do I have ...
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  • 5,231
132 votes
4 answers
356k views

How can I display the list of available WiFi networks?

My Ubuntu laptops's WiFi works fine on various Wifi networks. But the list of available networks accessed from the toolbar icon of nm-applet by no longer appears. I just see the known networks. The ...
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  • 2,471
131 votes
9 answers
304k views

After modifying /etc/hosts which service needs to be restarted?

After modifying /etc/hosts, which service(s) need(s) to be restarted for the change to take effect?
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  • 2,157
123 votes
9 answers
398k views

16.04 LTS wifi connection issues with Realtek RTL8723BE adapter

I discovered several issues with wifi connection after installing 16.04 LTS. First, wifi doesn't reconnect normally after sleep or hibernation. Sometimes the network icon turns into a "up and down ...
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  • 2,594
121 votes
15 answers
183k views

How can I capture network traffic of a single process?

I would like to examine the network traffic being handled by a single process, but simple network captures won't work since I am dealing with such a busy system (lots of other traffic happening at the ...
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117 votes
7 answers
240k views

A start job is running for wait for network to be configured. Ubuntu server 17.10

i just installed ubuntu server on my laptop and everything works fine except for the fact that at boot if the laptop is not connected to ethernet or in range of my wi-fi i get this message "A start ...
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  • 1,271
113 votes
5 answers
394k views

How to find all the used IP addresses on a network

In my work there is a lot of computer and I want make a joke. I can close computer over the network but finding IP addresses is hard to me. How can I easily find all online IP adresses from 192.168.1....
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106 votes
3 answers
150k views

netstat or alternative in docker ubuntu server 16.04 container

Was netstat removed in 16.04? Is there an alternative to netstat available in 16.04? Or how do I install netstat in 16.04? I am running an ubuntu:16.04 container in docker for Windows, it seems that ...
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104 votes
12 answers
454k views

List all MAC addresses and their associated IP addresses in my local network (LAN)

How can I list all MAC addresses and their associated IP addresses of the machines connected to my local network (LAN)?
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104 votes
7 answers
262k views

In VirtualBox, how do I set up host-only virtual machines that can access the Internet?

In setting up virtual machines with VirtualBox, I often want the following characteristics VM has a static IP host can access VM without port forwarding VM can access the internet I can move my ...
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103 votes
8 answers
252k views

How to run "sudo apt-get update" through proxy in commandline?

In my office i want to update and download through (wget) and here they are using proxy? How can i do this by commandline?
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  • 3,383
101 votes
5 answers
489k views

How to successfully restart a network without reboot over SSH?

In Ubuntu 14.04 neither sudo service networking restart nor sudo /etc/init.d/networking restart do anything any more. They also both exit with code 1. Something has obviously changed (or half changed) ...
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  • 2,391
96 votes
7 answers
251k views

How to network two Ubuntu computers using ethernet (without a router)?

How can I network two Ubuntu computers, so that they can "see" each other at an IP address?
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94 votes
7 answers
659k views

No internet connection on Virtualbox (Windows 7 as guest, ubuntu 13.04 as host)

Internet works perfectly on host (Ubuntu 13.04, 32 bit, fully updated) but cannot connect to internet on guest Windows 7 (under Virtualbox 4.2). Have tried NAT and Bridge Network - none worked. I had ...
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  • 943
91 votes
4 answers
198k views

How to inspect outgoing HTTP requests of a single application?

My application is sending HTTP requests to some server and I want to see the actual data that it is sending out. Some specifics I would like to see: Request method (GET/POST/PUT, etc.) Content-type ...
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  • 2,427
90 votes
7 answers
143k views

How do I find out the name of the SSID I'm connected to from the command line?

Neither iwconfig nor iwlist seem to be able to do this for me.
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89 votes
4 answers
99k views

apt-get update stuck: Connecting to security.ubuntu.com

When I run apt-get update on my machine it gets stuck at: 100% [Connecting to security.ubuntu.com (2001:67c:1562::15)] [Connecting to archive.canonical.com (2001:67c:1360:8c01::16)] I have made no ...
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  • 7,155
87 votes
9 answers
351k views

How to see all computers connected to a network

I am in a LAN and there are 3 Ubuntu, 2 Kubuntu, 2 Windows XP and 2 Windows 7. What commands or tools are available to see what PCs are connected to the LAN that it shows the name of the PC and the IP....
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86 votes
7 answers
92k views

Last upgrade crashes network manager (no internet connection, no applet)

While upgrading today, something caused my wireless network manager to disappear. Not even connecting via wired connection. This error is being shown by files: **(nm-applet:2716): WARNING **: Could ...
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86 votes
3 answers
89k views

How I can limit Download/Upload bandwidth?

How I can limit Download/Upload bandwidth for: Entire OS. One network interface. Single application.
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  • 1,516
83 votes
4 answers
220k views

ssh -L (error: bind: Address already in use)

Pretty simple, I know that this has happened to me before. Couldn't find a good answer on AU. I was running an ssh session with ports bound: ssh -L 3000:<server_name>:22 I just lost my ...
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  • 1,415
83 votes
9 answers
131k views

Ubuntu 20.04 Network Performance Extremely Slow

I just upgraded from Ubuntu 18.04 to 20.04 on one of the Dell XPS 13 machines, and the network performance is abhorrent. Internet speed is very fast from a google speed test (>300Mb/s for both upload ...
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  • 1,659
82 votes
9 answers
49k views

Uncomplicated Firewall (UFW) is not blocking anything when using Docker

This is my first time setting up an Ubuntu Server (14.04 LTS) and I am having trouble configuring the firewall (UFW). I only need ssh and http, so I am doing this: sudo ufw disable sudo ufw reset ...
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  • 2,161
82 votes
3 answers
205k views

How to share files through the local network?

I have a desktop (Ubuntu 13.04 & Win 7 Home Premium) and a Laptop (Ubuntu 12.04), both having WiFi adapters. I also have a WiFi router connected to internet which both my computers can access. I ...
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  • 1,215
80 votes
7 answers
98k views

How can you monitor total internet data usage across reboots?

Some broadband providers impose a monthly download limit, charging extra if you go over. It is also quite easy to exceed some of the lower limits just by installing/updating packages and 'normal' ...
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  • 35.9k
80 votes
5 answers
91k views

Wireless networking not working after resume in Ubuntu 14.04

[Update]: The same problem exists in Kubuntu and is solved in the same manner. [Solved]: By applying the following command nmcli nm I got the following: Before suspend RUNNING STATE ...
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79 votes
4 answers
108k views

What is difference between localhost address 127.0.0.1 and 127.0.1.1

I am just learning using Ubuntu and when I tried to configure the DNS, I need to deal with something call localhost, loopback interface. Can anyone explain me the differences between them and the ...
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  • 891
76 votes
4 answers
76k views

What are the significant differences between tracepath and traceroute?

I recently read a bit of an article on HowToGeek that has me scratching my head a little. I've got fairly little experience with Linux though, so forgive me if this is entry-level: "The ...
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  • 813
75 votes
6 answers
248k views

"waiting for network configuration" Problem

This problem happens sometimes when ubuntu starts up. You can't really boot to the interface sometimes. Splash Screen with the 5 dots and a message saying: waiting for network configuration ...
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  • 4,741
75 votes
7 answers
99k views

How to monitor bandwidth usage per process? [duplicate]

I am using Ubuntu 14.04. My internet connection is pretty slow (512 kbps). Sometimes I see that I have no software running which should download anything from the internet, but the system monitor ...
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  • 2,175
75 votes
2 answers
294k views

restart network interface after editing /etc/network/interfaces [duplicate]

restart the network service: service networking restart When I give the above command I get something like stop: Unknown instance: networking stop/waiting I would like to know if the network ...
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75 votes
3 answers
182k views

What is MASQUERADE in the context of iptables?

In iptables many times I see the target MASQUERADE. What is that? I searched and found lots of things. But I need someone to explain to me what MASQUERADE is in an easy to understand way? An ...
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74 votes
8 answers
184k views

What's the best way to SSH to machines on the local network?

I have 2 computers, one that I use and one for the kids. I want to be able to ssh into their computer to control it (like to shut it down etc) but am curious the best way to do this. We both are in ...
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