Managing and using network connectivity on a unix system

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6
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100 views

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 ...
4
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29 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 ...
4
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0answers
40 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). ...
4
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88 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 (...
4
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65 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 ...
4
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155 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. ...
4
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0answers
28 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 ...
4
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0answers
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. ...
4
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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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647 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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213 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= 00:16:3e:24:26:...
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24 views

SoftIRQs and Fast Packet Processing on Linux network

I have been reading about performance tuning of Linux to get the fastest packet processing times when receiving financial market data. I see that when the NIC receives a packet, it puts it in memory ...
3
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41 views

Why “echo f” in the case of clearing conntrack table doesn't work on debian?

Many people don't clear the conntrack table when they want to reload their firewall rules. When you have some ESTABLISHED connections, all the sessions won't be affected when you add a rule that ...
3
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67 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 ...
3
votes
0answers
87 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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19 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 ...
3
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0answers
39 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 ...
3
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0answers
87 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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260 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 ...
3
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165 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 ...
3
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0answers
252 views

Difference between MTU for a route and MTU for an interface

There is a server I connect to over the WAN and somewhere over the route there is packet loss unless I set the interface MTU to 600: ifconfig eth0 mtu 600 Doing this causes problems with ...
3
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73 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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578 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 ...
3
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158 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 ...
3
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113 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, ...
3
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196 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 ...
3
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0answers
809 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 (...
3
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0answers
82 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 ...
3
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0answers
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 ...
3
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0answers
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?
3
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252 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 ...
3
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0answers
310 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 /usr/lpp/bos....
3
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0answers
240 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 -...
3
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0answers
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 ...
3
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0answers
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 -...
3
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0answers
229 views

router latency measured by tcpdump increases

I am using tcpdump to measure latency on a linux router, i.e. the delay experienced by packets as they pass through the router (made of Ubuntu 10). For this purpose, I captured packets in the IN and ...
3
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0answers
760 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 ...
3
votes
0answers
790 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 ...
2
votes
0answers
8 views

Block port on boot2docker vm on virtualmachine

I have Boot2Docker image running in VirtualBox on my mac. I use Kitematic to run docker on my Mac. I have activemq docker running, on port 32769 in boot2docker vm. I have application running which ...
2
votes
0answers
18 views

Large TCP backlog in docker container, but no visible connections

In a setup with three docker instances, one running haproxy and two others running a flask-based python application through uWsgi, we run into a situation after about a day where no new connections is ...
2
votes
0answers
14 views

Bluetooth Tethering, no IPv4 adresse at interface bnep0

I want to tether my mobile internet from my smartphone (OnePlus One, Android) to my Laptop (Debian 8). I want achieve this without using external tools. At the arch wiki page (https://wiki.archlinux....
2
votes
0answers
23 views

Multicasting with a Debian Router

I have a local network and I want to use NTP in multicast mode on this LAN. The first step to do this is to get multicast networking to work first. In the network I have 5 Debian machines all ...
2
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0answers
25 views

How to share a DHCP Server(Debian) that is created on VMware to other PC in the same switch

I've created a dhcp server(in Debian) on VMware. When I launch a new virtual machine on the same computer it works fine, it receives an IP address from the DHCP server. But how to connect other ...
2
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0answers
46 views

Network traffic monitor “nettop” morphing away from expected results

On Mac, I open a new shell and enter nettop. For a split second I see chrome (as I expected) and some other things going on (had to record screen to catch them); then I'm only shown data on ...
2
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0answers
65 views

ftp failing to retrieve directory listing

I'm trying to connect to my ftp server but I'm getting Status: Disconnected from server Status: Connecting to 127.0.0.1:21... Status: Connection established, waiting for welcome message... Status: ...
2
votes
0answers
42 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 ...
2
votes
0answers
20 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 ...
2
votes
0answers
70 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 ...