Questions tagged [networking]
Computer networking is the connection two or more computing devices for transmitting and sharing data. The devices use common communication protocols over a physical or wireless connection. Use this tag for questions about managing and using network connectivity on an Ubuntu system.
23,121
questions
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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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votes
25
answers
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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?
542
votes
8
answers
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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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406
votes
43
answers
1.9m
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 ...
335
votes
17
answers
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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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328
votes
18
answers
2.1m
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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 /...
- 4,812
315
votes
10
answers
1.3m
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 ...
- 3,751
304
votes
6
answers
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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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256
votes
10
answers
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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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241
votes
8
answers
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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 ...
- 5,115
201
votes
1
answer
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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?
- 118k
186
votes
3
answers
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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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171
votes
9
answers
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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 ...
- 1,811
165
votes
12
answers
140k
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 ...
- 2,165
164
votes
6
answers
50k
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 ...
- 2,103
161
votes
4
answers
478k
views
How can I display the list of available Wi-Fi networks?
My Ubuntu laptop's Wi-Fi works fine on various Wi-Fi networks. But the list of available networks accessed from the toolbar icon of nm-applet no longer appears. I just see the known networks. The list ...
- 2,941
160
votes
8
answers
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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 ...
- 1,782
155
votes
9
answers
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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?
- 2,437
148
votes
5
answers
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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?
- 5,464
140
votes
3
answers
230k
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 ...
- 5,751
140
votes
4
answers
141k
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. ...
- 8,300
133
votes
18
answers
201k
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 ...
- 17.5k
124
votes
9
answers
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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 ...
- 2,624
119
votes
5
answers
432k
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....
user84277
113
votes
8
answers
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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?
- 3,563
110
votes
3
answers
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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 ...
- 2,325
109
votes
12
answers
493k
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)?
- 84.9k
109
votes
11
answers
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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
...
- 2,821
109
votes
10
answers
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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 ...
- 2,129
105
votes
9
answers
302k
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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?
James
104
votes
7
answers
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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 ...
- 3,207
102
votes
7
answers
182k
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.
- 2,413
101
votes
5
answers
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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) ...
- 2,391
100
votes
4
answers
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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
...
- 2,617
96
votes
7
answers
710k
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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94
votes
9
answers
394k
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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....
- 213k
94
votes
6
answers
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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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92
votes
5
answers
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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 ...
- 1,565
92
votes
4
answers
134k
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 ...
- 1,021
91
votes
3
answers
226k
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 ...
- 10.3k
90
votes
5
answers
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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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89
votes
3
answers
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views
How I can limit Download/Upload bandwidth?
How I can limit Download/Upload bandwidth for:
Entire OS.
One network interface.
Single application.
- 1,546
86
votes
7
answers
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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 ...
- 1,041
86
votes
3
answers
228k
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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82
votes
10
answers
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views
How do I renew my DHCP lease?
Short of rebooting, how can I release and renew my DHCP lease? It would be useful to know a GUI and terminal method.
I'd especially like to know if there is a means to do this without requiring admin ...
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82
votes
4
answers
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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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81
votes
6
answers
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views
How can I make VirtualBox guests share the host's VPN connection?
Question
When I start my VPN on my ubuntu desktop computer which acts as a router, the attached subnet loses internet connectivity, but is still accessible (LAN). Ideally, I would like to know how to ...
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votes
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answers
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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 ...
80
votes
7
answers
227k
views
How to disable IPv6 permanently?
How can we disable IPv6 system wide via terminal commands?
I've read editing /etc/modprobe.d/aliases
and replacing:
alias net-pf-10 ipv6
with:
alias net-pf-10 off
alias ipv6 off
Is this safe to ...
- 809
79
votes
8
answers
234k
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 ...
- 1,087