Managing and using network connectivity on a unix system

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1answer
26 views

Find out with a command if we can listen on a port

It is possible with a simple Unix command to find out if we can listen on a port or not? I'm building an application in which the user has the permissions to change the port. I have to check though ...
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0answers
111 views

rp_filter dropping packets in linux bridges+vlan_tagged interface + tap interfaces configuration

I've a linux bridge which has it's first interface as a eth0.123 (VLAN tagged interface) & one or more tap interfaces created by kvm. (libvirt+kvm VM) [root@compute1 ~]# brctl show bridge name ...
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3answers
15k views

How to bring up a wi-fi interface from a command line?

I can't figure out how to properly bring up the wi-fi card on my laptop. When I turn it on and issue $ sudo iwconfig wlan0 txpower auto $ sudo iwlist wlan0 scan wlan0 Interface doesn't support ...
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0answers
117 views

Network firewall on CentOS, host cannot be resolved?

I have a centos machine and I am trying install some dependencies using yum. When I do this I keep getting a message saying the host cannot be resolved. I was told the previous person that used the ...
1
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1answer
30 views

Virtual ethernet is not getting its static ip on hotplug

I need to configure an ethernet interface to get its ip address dynamically if there is a dhcp server out there, and always have a static ip whether there is a dhcp server is present or not. I have ...
1
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1answer
37 views

Application specific DNS problem?

I'm working on a live stream transcoder application using nginx + ffmpeg. Everything works fine when I use avconv to transcode, but if I use ffmpeg, I get this error: [tcp @ 0xb4e9da0] Failed to ...
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1answer
98 views

Kali linux network connection icon missing

I was trying to setup a vpn connection in Kali linux but i don't know what did i do that network connection icon (screen top right) is missing and i can't connect to internet! How do i fix it?
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1answer
29k views

How to connect to Internet in Kali Linux after changing IP address manually?

I have a problem in my Kali Linux. I cannot connect to the Internet after changing my IP address using this command: ifconfig eth0 198.168.198.130 netmask 255.255.255.0 up After this, when I open ...
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0answers
37 views

Network communication between two nodes in a Hadoop cluster

I am running a 7 node hadoop cluster with each box running Ubuntu 12.04. It is running CDH4 setup using Cloudera Manager. It was already setup and running when I came in but now I'm running into a ...
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1answer
53 views

Received DUP when using ping. What should I do?

I was pinging Google last night and one of them came back as DUP(!). I did some reading and I found this in the man pages on ping(8): Damaged packets are obviously serious cause for alarm and ...
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1answer
1k views

nmap failed to determine route

I have set about trying to learn nmap, though for some reason it does not work I keep getting the same error, the only time it works is when I specify loopback address, this is the error I get ...
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2answers
61 views

why I can't see the interface in Linux Debian

I set an eth1 interface in Linux Debian, and I rebooted after that, but I don't see it when I would like to use the sudo ifconfig, or ifconfig command (as root) only the eth0 interface. The settings ...
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0answers
18 views

Setting gateway to dynamic IP

My home router (given by ISP, must use it) does not accept static IP connections. I need to set the gateway for eth0 pointing to wlan0. I've succeeded in setting gateway in etc/network/interfaces/ to ...
4
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2answers
33k views

Host unreachable and I do not get why

I can not open a specific website. This is a website hosted by our company, and I know it is up. However, these are my symptoms: VARIABLES: host.com - the website I can not open x.x.x.x - the IP of ...
1
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1answer
34 views

How to return Uptime of successful OpenVPN connection

I'm trying to figure out how to return the UP Time of a successful OpenVPN connection. I've tried different variants of the following code: #!/bin/bash TMP=$(grep 'tun0: link up' /var/log/syslog* | ...
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2answers
92 views

how to test if can connect to port in rhel 7 (telnet client?)

On my local machine some network application is launched on port 3333 and I want to check that it "accepts connections". In this case in Windows I just type telnet to launch telnet client, and then o ...
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4answers
6k views

Is there a way to set network proxy system-wide?

If I want to have GNOME applications (as well as Firefox and Chrome) access the network through a proxy, I need only use gnome-network-properties (a nice and simple GUI I must say). For other apps ...
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1answer
931 views

Why does't stopping the nginx server kill the processes associated with it?

When I stop nginx like this on ubuntu 12.04, I get the following errors: $ sudo service nginx stop Stopping nginx: nginx. $sudo service nginx start Starting nginx: nginx: [emerg] bind() to 0.0.0.0:80 ...
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0answers
24 views

Find out the cause of “Hard Block”

I have a Beaglebone Black I managed to install wifi drivers, find networks to connect to, but I always fail to do so. Apparently rfkill is setting Hard Block which is ( correct me if I'm wrong) ...
0
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1answer
42 views

trouble bridging tap0 and tap1

I have a GNS3 router that is connected to tap1 in my host. On the other hand, I have an user application connected to tap0 running locally in my host. I can ping both the router and my application. ...
0
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1answer
576 views

Raspian, Huawei E303, Public IP address

After configuring Raspian linux and a Huawei E303 3G USB stick, I am stuck accessing the machine from the Internet by its public IP address. Details: The E303 stick was configured to work as an ...
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0answers
46 views

How to exclude LAN traffic with iptraf-ng?

I'd like to use iptraf-ng to see how much data my machine is sending/receiving from the Internet, but I want to exclude traffic on my LAN as I am only interested in data going off-site. I have ...
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4answers
8k views

hostapd will not start via “service” — but will start directly

I am having trouble getting hostapd to start as a service. It fails when I try to start it: $ sudo service hostapd start [FAIL] Starting advanced IEEE 802.11 management: hostapd failed! From what ...
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0answers
28 views

How is it possible to send ping to all 127.0.0.0/8 successfully? [duplicate]

I have some wonders about 127.0.0.0/8 network and have 2 question about it. Firstly, why 127.0.0.0/8 is not considered as private network? I wonder this because wiki page does not mention about it. ...
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4answers
37k views

Why the default eth0 interface is down by default on CentOS?

I am already a little bit familiar with Linux distros like Debian or Ubuntu (yeah, very similar) but I wanted to try Red Hat based - CentOS 6.2 . I have installed it on my Windows 7 host in virtualBox ...
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0answers
41 views

Where to find a basic tutorial/book on Linux networking? [closed]

I am not sure this question is eligible for this forum, so if not, please provide which forum is more suitable for this question. What I am looking for is a basic introduction in how networks work ...
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0answers
56 views

how to route traffic on port to ip:port on linux?

I'm trying to route all traffic on port udp 5000 to udp 192.168.0.1:12333 with the following command: $ iptables -t nat -A PREROUTING -p udp -m udp --dport 5000 \ -j DNAT --to 192.168.0.1:12333 ...
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1answer
386 views

Using source routing (LSRR) - any ideas?

What I want to do is conceptually very simple, but I can't find any information or help about how to go about doing this. Basically, I want to configure my networking to use source routing (LSRR). ...
2
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0answers
85 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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0answers
28 views

Where do the frame overruns come from?

I have a network setup like this: +------------------------+ | Switch | | | +---------+-----+----+---+ | | | | ...
2
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1answer
193 views

recvmsg returns 'EAGAIN (Resource temporarily unavailable)'

After a recent server move, we are troubleshooting this wierd issue of one of the server losing n/w connectivity for no apparent reason and regaining the connectivity in a few seconds or minutes. ...
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0answers
49 views

How to bridge a VM to public IP

I wish to to assign the IP from my eth1:2 to a VM; I also have no use of this IP for the host, it would be desirable to be exclusive to the VM. I've ended up with a setup just like this (eth1:1, ...
0
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2answers
65 views

How to get the list of ports which are free in a Unix server

I have a requirement to know which all ports in my Solaris machine are free to be used for any kind of network communication. I tried the netstat -a command. But the information returned didn't give ...
1
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1answer
1k views

Problems with Dell Wireless 5570 HSPA+ Mobile Broadband card

I've got a new Dell Latitude e7440, and a Dell Wireless 5570 HSPA+ mobile broadband card. I cannot get the broadband card to work. I can see the card: # lshw .... *-network DISABLED ...
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3answers
132 views

Generate networking configuration files using sed and bash

I am a bit rusty on my scripting abilities and am trying to find a good starting point for creating a script that creates files (generating new file names) and edits the IP address in the file by ...
0
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1answer
36 views

Understanding NAT concepts

I began learning networking on Linux, and I am looking for a way to associate a particular IP to a particular MAC address (i.e. a way to edit the NAT table?). Actually I am trying to assign some IPs ...
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0answers
31 views

Using PulseAudio to receive RTP audio stream

I'm trying to set up simple communication between my Ubuntu distro and my Rasbian distro on the raspberry pi. I'm more concerned about the rPi side of this project. I've been looking around the ...
0
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1answer
34 views

Understanding linux Bridging

I have started learning networking and recently been through bridging in Linux. Bridge in Linux could be set in two ways as far as I have got by reading on internet i.e. either by bridge-utils ...
1
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1answer
430 views

wget is unable to resolve host address 80% of the time

I have a wget 'http://xxxx.net/somepage.asp?params@abc' in a bash file. When I run it, four out of five times it says: Resolving xxxx.net (xxxx.net)... failed: No address associated with hostname. ...
2
votes
3answers
111 views

Bridge/Router with custom logic

I've a Linux box with 3 network adapaters, which I'd like to configure as follow: Adapter A is connected to computer A Adapter B is connected to computer B Adapter C is connected to the Internet. ...
2
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1answer
24 views

what happens during nic master failover?

During NIC master failover, will the mac address of bond0 change?
2
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1answer
109 views

reset Ethernet bonding without rebooting

I have the following Ethernet bonding configuration: old configuration: bond0 eth0 eth1 bond1 eth2 eth3 new configuration : bond0 eth0 eth2 bond1 eth1 eth3 I have made the ...
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0answers
23 views

Use more than one provider [closed]

I wanna know of it is possible to bond my network interfaces, so that I can use two or more different providers and combine the speed of those. Is this possible and how?
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2answers
750 views

Which user group can use the 'tap' net device?

I use the 'tap' net device with KVM to get my vm connect to the Internet. But I have to be root, or use 'sudo', which is inconvenient. I think I can put my user account into some group so I can access ...
1
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1answer
17 views

Xen and Networking

I'm using Xen 4.1 I have a (debian) host with 1 ethernet adapter on 172.16.1.0/24 range, static configuration. I want to have various (centOS) guests, that will be on a different network: ...
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0answers
23 views

How can I display an altered Network-icon to show when downloading is in progress? [closed]

Summary: When downloading is in progress, how can I change the appearance of the icon (in the Panel) which shows that the Network Connection is enabled? I realise this means using a different icon. I ...
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2answers
1k views

WiFi not working after restoring from hibernation (authentication times out)

My Intel 6205 wireless network card does not work after hibernating. It sometimes also does not work on boot, failing in the same way. Occasionally, it also stops working after ~10 minutes of ...
1
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1answer
72 views

/etc/network/interfaces not loading correctly at boot

I'm trying to use my Beagleboard Black as a wireless access point (using hostapd and dnsmasq). I've found that I can connect (I'm assigned an IP address, get a DNS Server and Default Route), but I am ...
1
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1answer
21 views

Network translation, one to one, not one to many

Desired scenario: a small subnetwork of Linux machines, all accessible through another Linux machine (acting as an IP router). These machines would be pre-configured with addresses on a private ...
4
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1answer
447 views

Fedora 20 dosen't accept correct PIN for mobile broadband

I have a problem with the WWAN (Qualcomm Gobi 2000) in my Lenovo ThinkPad W510. I can not unlock my SIM card with the correct PIN. I enter the PIN in this dialog and after this I get immediately ...