Managing and using network connectivity on a Ubuntu system

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18
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4answers
5k views

How can an application (like Firefox) be forced to use a certain network interface?

I've two interfaces: eth0 and wlan0 on a notebook. Possible use cases: eth0 grants me Internet access, and wlan0 is currently connected to a router which does not have Internet-connectivity. For ...
17
votes
3answers
28k views

How do I route my internet through a SSH tunnel?

Old Q How do I setup an OpenVPN server without root privileges? Is there a way to setup an OpenVPN server without root privileges? E.g. with configuration files in my home directory? If yes, how do I ...
17
votes
2answers
15k views

What does “.local” do?

I've got several Ubuntu machines on my network at home, but the DNS is provided by a windows server (2K). When I ssh to them from another , if I ssh to them as "machine" I can't connect, but if I ...
17
votes
2answers
7k 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 ...
17
votes
3answers
7k views

Why there is no nsenter in util-linux?

I frequently using nsenter command for my purposes in my main system under Arch Linux. Now I have to work on Ubuntu to test my apps on it, but there isn't nsenter in util-linux. Maybe it's a separate ...
17
votes
3answers
21k views

Ubuntu 14.04: Can't connect to new password protected wifi network

After upgrading to Ubuntu 14.04 I can't connect to any new WPA2 wifi access points. Existing ones work. Here is a pastebin of the syslog output: http://pastebin.com/QVgmRmXp Here is an error that ...
17
votes
3answers
70k views

What's the default /etc/network/interfaces?

I messed up my network configuration. Can anyone help me and copy the default /etc/network/interfaces?
17
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2answers
18k views

Problems with networking after suspend [closed]

I have some problems on my Asus notebook since I upgraded to Ubuntu 13.10: Networking (wifi and lan) won't work after resume from suspend. I've seen many posts about this but they wouldn't work for ...
17
votes
4answers
28k views

resolv.conf doesn't get set on reboot when networking is configured for static ip

I'm experiencing what appears to be a name resolution issue in Ubuntu 12.04 Server edition when configuring my computer to use static ip. In /etc/network/interfaces: # The primary network interface ...
17
votes
2answers
9k views

Where to add the Pre-Shared Key for the Server Authentication with Network Manager for L2TP/IPSEC?

Previously, I was trying to figure out how to install the L2TP/IPSEC manager code. I guess Ubuntu/Canonical switched away from OpenSwan to StrongSwan, but didn't really announce it. So that was ...
16
votes
7answers
3k views

What non malicious uses are there for ping's flood (-f) option? [closed]

I have been reading up on common ways in which people attack each other on the internet through things like DDOS attacks etc, and how one would defend oneself from such attacks, and I have come across ...
16
votes
3answers
25k 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.
16
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2answers
90k views

Sharing Connection to other PCs (Via Wired Ethernet) [duplicate]

I have two desktop PCs I use frequently, both running Ubuntu 12.04. One is connected to the internet via wireless, and the other has no wireless card. Is there any way I can share my internet ...
16
votes
3answers
104k views

Using scp to copy files from remote to home machine

This is probably a simple error, but I can't work it out. My computer hostname is Felix (hostname -f returns Felix) I am trying to move a file from my university account to my home computer using scp. ...
16
votes
1answer
2k views

How to build a simple chat using netcat?

I am currently working on a project and I have implemented a simple chat application using the netcat libraries. The client is prompted to enter port number and the command nc -l -p xxxx where ...
16
votes
1answer
24k views

Should I set up my CUPS Printing to use IPP, LPD or URL?

When I got to add a network printer, I'm always confronted with the same dilemma: Do I set up the printer via IPP, LPD, or using it's IP address (AppSocket/Jetdirect?) and why? What are the ...
16
votes
2answers
50k views

How can I set my linux box as a router to forward ip packets?

I am doing a network experiment about ip packet forwarding, but I don't know why it does work. I have a linux machine with two network interfaces, eth0 and eth1 both with static IP address (eth0: 192....
16
votes
2answers
5k views

How do I run Juju on a local server?

I'd like to use juju on my server at home to get to know juju and play with it. I have multiple computers and would like to access what's on the server from any of them. When I went through the ...
16
votes
9answers
149k views

How to configure proxy authentication to work with Ubuntu Software Center?

I have tried put in apt config Acquire::http::proxy, and in Network>Network proxy with and without user:password@server:port and using environment variables http_proxy and https_proxy. Nothing seems ...
16
votes
2answers
42k views

Network Manager Icon disappeared 14.04

So a couple of weeks ago my network manager icon stopped appearing; I still get automatically connected to my saved networks and the internet works fine, etc. If I go into System Settings and look at ...
16
votes
2answers
6k views

How to configure preferred network for internet?

I am connected to a LAN network and wireless network. Both provide access to internet. Sometimes when the internet on LAN is not working, the browser simply throws an exception instead of switching ...
15
votes
7answers
27k views

Is there a program to see channels used by wifi networks (similar to Vistumbler) in Ubuntu?

I need to see the channels used by all wifi networks in range in order to improve my wifi connection by selecting the channel to be used by my modem (a procedure related to the 'freebox' modem). In ...
15
votes
2answers
18k views

nameserver 127.0.1.1 in resolv.conf won't go away!

I've read that I should have nameserver 127.0.1.1 in my /etc/resolv.conf file only if my machine has its own DNS server. Since it doesn't, having it causes problems. But no matter what I do I can not ...
15
votes
6answers
12k views

Ubuntu One behind a proxy, how to make it work?

I am behind a web proxy server at work (no authentication) and I have set it up in Gnome (configuration applied system-wide). It works fine for accessing internet with a browser, but numerous ...
15
votes
1answer
23k views

How to allow remote connections to Flask?

Inside the system, running on virtual machine, I can access the running server at 127.0.0.1:5000. Although the 'remote' address of the vm is 192.168.56.101 (ping and ssh work fine), I cannot access ...
15
votes
1answer
35k views

What are ICMP redirects and should they be blocked?

After enabling ufw and the Tiger security auditor, I see warnings saying: The system accepts ICMP redirection messages What are ICMP redirection messages? Should they be disabled for security ...
15
votes
7answers
35k views

Two ethernet ports on motherboard. How can I get double the bandwidth?

Direct Question: My evga classified motherboard has two ethernet ports. I want to use them simultaneously to improve the speed of a remote connection. (Yay for programming remotely). How do I do ...
15
votes
1answer
41k views

What does the dns-search option mean in /etc/network/interfaces?

Can anybody explain to me about the dns-search directive in /etc/network/interfaces file: iface eth0 inet static address 192.168.3.3 netmask 255.255.255.0 gateway 192.168.3.1 dns-...
15
votes
4answers
39k views

Network not starting up on boot

Basically my network won't start. Can't use wired connections. To make it a further brain-scratcher, when booting into recovery, and using the network console, the network comes up and works. Outside ...
15
votes
6answers
15k views

Why is my Internet connection randomly dropping?

Ever since I have installed 12.04 (clean install not an upgrade), I have been having a drop in the Internet connection. The drop in the connection can be anything from 15 seconds to about 3 mins, and ...
15
votes
4answers
18k views

Wifi keeps disconnecting and extremely slow at low signal - Ubuntu 13.04

First off, I just want to say that I work as an IT engineer (Windows Desktop/Server etc) so I am willing to go right down to the ground when it comes to advance technical troubleshooting. ...
15
votes
0answers
12k views

Command to know my external IP address? [duplicate]

How can I get my external IP address using the Command Line?
14
votes
3answers
16k views

Configuring Firefox to use a proxy from the command line

I'm looking for a way to tell Firefox to use a proxy in Ubuntu Ludid (10.04.1 LTS). I'm installing Ubuntu semi-automatically on several identical machines. For this, I use a script that, amongst ...
14
votes
3answers
66k views

KVM Bridged Network Not Working

I just installed KVM on my Ubuntu Server according to this guide : https://help.ubuntu.com/community/KVM/Installation Then prepared a bridged network as shown in here : https://help.ubuntu.com/...
14
votes
2answers
15k views

persist port routing from 80 to 8080

I use amazon EC2 instance which works via ubuntu. By default according security restrictions I can't bin my application to port 80, so I just bind it port 8080 and then set routing redirect from port ...
14
votes
3answers
50k views

How to successfully restart a network without reboot? [duplicate]

When I am using Ubuntu, sometimes the network goes down and there is no option to bring back the wired network. There is always option for wireless, but no option for wired network. In such case I try ...
14
votes
1answer
4k views

How do I ignore a proxy if not available?

Following the instructions in Best way to cache apt downloads on a LAN?, I've set up a caching proxy in my local network. Since that machine is not always up, I'd like to be able to refresh the ...
14
votes
3answers
8k views

How can I set up a Dynamic DNS fetching service on Ubuntu Server?

I've created accounts and hostnames within my http://no-ip.org/ account, which is by far the most commonly used service for my type of server. Can somebody walk me through the configuration process ...
14
votes
2answers
9k views

Switching a server to static IP from DHCP

I am running an Ubuntu 10.04 server installation and I recently had to switch it from DHCP to static ip. I edited /etc/network/interfaces file and switched iface eth0 inet dhcp to iface eth0 inet ...
14
votes
6answers
6k views

No more AnyConnect compatible vpn transport in Ubuntu 16.04?

Following my previous experiences with setting up Cisco AnyConnect VPN connections on Ubuntu 14.04 I tried the same approach here by installing packages: sudo apt-get install -y network-manager-...
14
votes
3answers
8k views

Is there a tool for validating /etc/network/interfaces files?

I always like to test new config files before deploying them--with tools like apachectl configtest and named-checkconf. It's rare that mistakes crop up, but catching them before deployment ...
14
votes
1answer
5k views

Automatically disable wifi (wireless) when wired?

What's the best way to automatically disable my Wifi/wireless connection whenever I plug in a wired Ethernet cable? I'd like it to be re-enabled when I later unplug the wire. Also, I sometimes like ...
14
votes
4answers
14k views

docker.io DNS doesn't work, it's trying to use 8.8.8.8

I have a new Ubuntu 14.04 install, and want to use Docker to run my old stuff that needs 12.04. DNS inside Docker doesn't work. My laptop's resolv.conf looks like: nameserver 127.0.0.1 Which doesn'...
14
votes
2answers
499 views

Identify “rogue” internet accessing Applications

At the moment I have an application/service/widget/plugin/cronjob whatever, accessing the internet on a regular basis. I could go into the details of my specific issue but I'd rather have an answer ...
14
votes
3answers
2k views

How do I restrict user bandwidth usage?

I want to restrict each user to 300 gigabytes of internet usage per month. Are there any GUI or command-based tools to manager my users' bandwidth?
13
votes
7answers
2k views

I accidentally deleted the network-manager and don't have access to internet anymore

I cannot connect to any wifi connection since I deleted the network-manager. Is there any way to get it from another computer and then install it on mine or is there a way I can get an internet ...
13
votes
3answers
9k views

How to monitor, who is pinging me?

Is there a way to know who is pinging my PC on my network. Is it possible to monitor all ICMP packets , how can i do that ?
13
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6answers
25k views

How do I stop my ethernet network connection from dropping?

My ethernet-based network connection doesn't stay up consistently. I'm running a ping against the gateway and it will: Work for a minute Freeze, time out, or give multi-second response times Repeat ...
13
votes
5answers
25k views

How do I connect my desktop and my laptop using an ethernet cable to transfer files?

I have an ethernet cable (not a crossover cable) to connect my laptop and my desktop ubuntu machines. I want to transfer large amounts of data. Is it possible with such a cable? I believe that between ...
13
votes
1answer
1k views

How to tell which processes are uploading and downloading data (and how much)? [duplicate]

I can see in my System Monitor that data is being uploaded and downloaded, I can see in Etherape which sites it's connecting to and which protocol is being used. However without looking at the actual ...