Managing and using network connectivity on a unix system

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Simulate ethernet cable unplugged on a remote machine while staying connected

I am working from home on remote embedded Linux machine "X" via ssh. It has one physical network card. I need to simulate Ethernet cable unplugged condition on the same remote machine "X" , while ...
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147 views

Wifi cuts out after some time

I recently installed Debian on my laptop (after playing around with dozens of distros in VMs for a year or so), and while most everything has gone quite swimmingly I'm having some issues with my wifi. ...
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108 views

Disable networking only inside of a single terminal

I want to run a command in the terminal to disable networking, just in that terminal. How can that be accomplished? I'm running OSX. Note: I only want to disable the networking in that terminal. ...
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43 views

Queuing disciplines are per-interface, what happen with interfaces using same device?

I have read about queuing disciplines here http://lartc.org/. I understand that for instance band 0 of pfifo policy is prioritized over band 2 within same qdisc, but what happen when i have ppp0 and ...
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209 views

To what extent does LXC manage configuring the network interface in a container?

In the LXC config file we can specify an IP address for a container: lxc.network.type=veth lxc.network.link=br0 lxc.network.ipv4 = 10.1.0.35/16 lxc.network.flags=up lxc.network.hwaddr= ...
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55 views

How can I create a two-way voice communication system that works over the local network?

I wish to create a simple two-way voice communication system between two Linux computers running Debian-based distros (probably two Raspberry Pi Zeroes). Each computer will have a microphone and ...
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24 views

Ethernet intermittently fails to come up

I'm working with an embedded Debian system and I'm having trouble getting ethernet working consistently. Once every 5 or 10 times that eth0 is brought up something fails and I can't connect to it via ...
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35 views

How do I run a systemd oneshot service whenever my system gets a new IPv6 address?

I would like to run a systemd oneshot service whenever my system gets a new IPv6 address assigned to it from the network router (this would be on boot, and periodically throughout its uptime). ...
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77 views

Simulate a network cable unplugged without login all routes

I want to simulate unplugging a cable from a Linux instance. My initial response was ip link set eth0 down. However, this command has impact on higher-level networking functions, e.g. routes ...
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75 views

e1000 driver update with interfaces gone

Intel server with 3 LAN cards. Board Mfg : Intel Board Product : S5000PHB 06:00.0 Ethernet controller: Intel Corporation 82571EB Gigabit Ethernet Controller (rev 06) 06:00.1 ...
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17 views

download rate limiting based on network usage

I have a Debian Wheezy (Open Media Vault) server with a few different downloaders working most of the time. (Primarily FTP) I would like to be able to adjust the download limits of this server based ...
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57 views

How can I know which IP address of a host is reachable from another?

I don't particularly need a "solution" to something, I'd just like to understand more of the landscape here. So on my CentOS box, I installed a CentOS VM specifically for learning Puppet. When the ...
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36 views

Configuring a Linux Wi-Fi access point to redirect a one-word URL to http://192.168.42.1:8888

've created a Wi-Fi access point on a Linux box (thanks to hostapd). I'm trying to make it easy for clients to access the Freenet service that's running on said box. Ideally, the user would be able ...
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77 views

Dnsmasq problem with Linux network namespace

I have tried to use dnsmasq as the name server for virtual machines. On all the vm-s, /etc/resolv.conf indicates the vm need to access 192.168.15.3 to resolve the domain names. However, the interface ...
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240 views

Debian 8 : where are default static routes set?

i'm facing a strange problem with my newly installed Debian 8 box : default static routes are missing the 0.0.0.0 destination route. $ sudo route -n Kernel IP routing table Destination Gateway ...
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161 views

Can't connect to Virtualbox VM's static IP which is in a different subnet from the hosts's IP, but statically routed to the host HW addr

I have a physical server running Ubuntu Trusty (14.04) at a data centre where they assigned one IP address, as well as a /28 block (16 IP addresses, 14 usable) from a different subnet. They said that ...
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72 views

Linux Routing Question

I was wondering how it would be possible to have multiple IPv6 default gateways on CentOS linux. I currently have two interfaces with IPv6 (venet0 and tb0), both with different blocks routed to them. ...
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1k views

Is it possible to throttle upload bandwidth per `IP` basis using `tc`, `htb` and `iptables` ? (Download limitation not required)

Problem I've searched internet like anything but couldn't find much about limiting upload. The solutions given are not limiting IP basis like this one but LAN as a whole. +-----+ ...
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27 views

Radiusd(freeradius): User only for a special client

Is it possible to restrict a user from the "users" file to a special client? I try to use one radiusd server for two wifi access points but I will use one user credentials only for one access point ...
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526 views

Bridge interface - add default route

I used to connect my ubuntu 14.04 laptop on office network via eth0 and the route table gets updated with the office network gateway ip in auto mode. Now, i changed my /etc/network/interfaces ...
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147 views

Trickle not behaving as expected

I'm using Ubuntu Trusty 14.04 64 bits. I've installed trickle network shaper from repositories and I performed some tests: No limits I executed this command to test somehow my network download ...
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109 views

delay in IP route deletion

(Apologies if this is the wrong StackExchange for this question, but there does seem to be some confusion regarding appropriate targeting of IP networking questions) I am very much a network newbie, ...
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186 views

tc cbq doesn't work (no traffic limitation)

I've been trying to use cbq weight attributes after HTB failed to do so. I've tried using a command set I've found in an example just to verify it works (HTB works fluently) Here are the commands I ...
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768 views

VirtualBox guest machine as a nginx host

I have VirtualBox 4.3.12 with Fedora 20 and nginx 1.4.7 installed. Machine has Bridged Network interface and pings can be done both ways: from host machine (Windows 7) using ping 192.168.0.15 ...
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81 views

Configuring pulseaudio for receive mode

I am working on a project where I'll be running PulseAudio in receive mode on my raspberry pi. As for the server side, we've been writing a custom application on windows that will send an RTP audio ...
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3k views

Unable to start network, <IP> is already in use for device eth0, but its not

A wierd issue after we migrated some of our servers to a new DC. We assigned new IPs to all the machines and all the servers are working fine except one. It is not picking up the new IP address and ...
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47 views

Log if no network

I have a router with OpenWRT. I noticed that sometimes (during night time) I have no internet connection. How can I log when this happens?
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239 views

AppArmor Profile: Deny internet access

I want to deny the internet permission for some applications. Therefore, I tried first to deny the internet permission for ping, but it doesn't work. Here is the profile of /etc/apparmor.d/bin.ping ...
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2k views

Linux - Only first virtual interface can ping external gateway

I created 3 virtual interfaces with different MAC addresses all linked to the same physical interface. I see that they can successfully arp for the gateway (gw) and they can ping (the request is ...
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304 views

AIX NIM Master replicate / sync fails to an Alternate Master

I am getting a error when I try to replicate / sync my NIM database and resources to an Alternate NIM Master newly created in my environment: error replicating resources: unable to ...
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234 views

Raspbian: how ifplugd works on lo and other interface

On my raspbian, I'm wondering why ifplugd (link detection daemon for ethernet devices) is also running on the lo the loopback interface. The ps command displays: /usr/sbin/ifplugd -i lo -q -f -u0 ...
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628 views

How to setup networking for Linux Mint - VM when host machine uses a PAC file

My host is a Windows 7 x64 machine. The office network uses a PAC file for the LAN settings. So, under Internet Options -> Connections -> LAN Settings, I have Use automatic configuration script with ...
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1k views

Send print job to printer immediately without queueing, aka increase print performance

I have a ruby/rails web application, one action of which sends PDF files that have been generated by the app to a Xerox 4127 printer on the network. This is accomplished via shelling out and running ...
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0answers
1k views

I can SSH and HTTP, but not ping or access particular UDP services over my LAN

So I've encountered a weird problem when trying to set up a Linux server running a variant of CRUX Linux. I am trying to configure it to be a Teamspeak server, but no clients can connect. The ...
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3k views

SCTP support for Linux kernel 3.3.4-5.fc17.x86_64

I'm using Fedora 17 64-bit version, with Linux kernel version 3.3.4-5.fc17.x86_64. I installed lksctp using yum. sudo yum install lksctp-tools.x86_64 When I try to run sctp_status -H 127.0.0.1 ...
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759 views

tunneling FON traffic via Tor

I would like to tunnel the traffic of my FON router through Tor. For that I added a second network card to a local server and connected the FON router to it. Then I set up a DHCP server and configured ...
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785 views

Wireless rtl8187 freezes intermittently

I am using a wireless USB ALFA 036H. Linux Mint (32-bit) recognizes it without any drivers but it stops downloading/uploading and I have to reconnect to get it to work again. I tried to find a ...
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24 views

DHCP to assign different addresses for multiple interfaces and subnets

First of all, I'd like to point out that I've read any related questions asked here. So, on my desktop computer (running Ubuntu) I have three NICs - eth0, eth2, eth3. I have links connecting these ...
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14 views

SNR or signal and noise levels in ad-hoc mode

I am using the WiPi dongle which is based on the rt2800usb driver on my Raspberry Pis (running raspbian) in an ad-hoc network, and I can't seem to be able to get any SNR, signal or noise level ...
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46 views

How do I get Consul to work so I can get Docker Overlay to work?

I am running CentOS 7 with Docker. I am trying to install Consul on the Docker server. Consul is unzipped. The binary file works for showing the version. I ran this: echo $CONSUL_RPC_ADDR This ...
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46 views

Why would all our CLOSE_WAIT connections have 24 bytes in the receive queue?

We have an Apache reverse proxy that is having connectivity issues with the back-end. This results in timeout errors such as this: [Thu Apr 21 12:12:26.031207 2016] [proxy_http:error] [pid 64620:tid ...
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41 views

Change with the command iptables not reflected in the output of the command netstat

Scenario: A virtual machine UU (abbrev for Ubuntu) is serving a web-page. The web-page is accessible on CO (abbrev. for CentOS) which has the Virtual Box on which UU is running. However the web-page ...
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80 views

Configuring and Testing Freeradius on debian

I'm trying to set up a freeradius server on debian (LTS kernel 3.2.0.4amd64; Wheezy 7.10) it seems to want to use freeradius version 2.1.12 Installing the package wasn't a big deal (apt-get install ...
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30 views

why does nmap shows same ports sometimes as filtered and sometimes as closed?

When I'm scanning port range 4050-4060 of an smart metering device all ports are reported as closed: root@abc:~/rvm/dlms# nmap -p 4050-4060 192.168.1.242 Starting Nmap 6.47 ( http://nmap.org ) at ...
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58 views

How to debug what is stopping ping to respond on our server?

We used to have a sysadmin person months ago who had disabled ping response on one of our servers. But now we want to re-enable ping response. I tried to check if the ping was disabled from config. ...
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129 views

Create a script that connect to wifi, and if it fails fallback to ad-hoc network

I'd like to create a script that tries to connect me to the wifi specified by my wpa_supplicant conf, and if it fails, create a ad-hoc network. But I'm struggling with it. Here is what I do for now: ...
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16 views

Why does `ping -M do -s 8000` still work between hosts with different MTU values?

I have two hosts: alice (192.168.0.1, mtu 9000) bob (192.168.0.2, mtu 1500) They are directly connected with a cat 6 cable, with no switch in between. Why is it that I can still ping bob from ...
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15 views

ipv6 rule priority duplication

When I add ipv4 policy rules using ip rule add the resultant rules get added to the end of the policy table with decrementing priority from 32767 eg: # ip rule add lookup 8 # ip rule add lookup 9 ...
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42 views

SSH/web servers in Linux containers improve security?

Scenario: A 'gateway' machine functioning as a router and firewall, connecting a small LAN to the internet. The machine also runs a webserver (hosting a simple website) and an SSH server, providing ...
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29 views

Removing Incorrect WINS record

So I have a Ubuntu 14.04 server that I'm trying to get to run as a Domain Controller for a set of Windows machines. I've set up a Bind9 DNS and it works fine, pinging the nameserver gives the correct ...