Managing and using network connectivity on a unix system

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4
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2answers
14k views

No MAC corresponding to IP in `arp` table: how to troubleshoot?

I've got a Debian 7 linux machine and a TP-link MR3020 router attached to it via ethernet cable at eth0 interface, working in WISP mode meant to make it a client rather than an access point: I also ...
1
vote
1answer
315 views

OpenVZ bridged networked adapters won't work from sample configs

I've made a copy of the basic config and added the line: NETIF="ifname=eth0,bridge=br0" When I create a new machine and enter it I can't make the network adapter work yet creating an instance from ...
4
votes
1answer
649 views

NetworkManager connection sharing doesn't seem to NAT packets

After setting up network sharing the easy way on the Ubuntu machine, and getting an IP address via DHCP on the Arch Linux machine downstream, the Arch machine is able to ssh to the Ubuntu machine and ...
2
votes
1answer
938 views

Process calling getaddrinfo() at boot gets permanently stuck with bad /etc/resolv.conf?

I'm running pianod, a Pandora client/server, on a Raspberry Pi with Arch Linux ARM. I have pianod set up to run as a service at boot. It starts up before the network stack, so getaddrinfo() fails. ...
2
votes
4answers
6k views

How to change user agent on all http requests made from my machine with Squid intercepting proxy?

I'd like to change the user agent on all HTTP requests made from this machine. It's easy enough to change the user agent in each browser, but other apps also make http requests. It's vital I catch ...
4
votes
2answers
5k views

ethtool get permanent MAC address returns all 0's

I need to read permanent (burned-in) MAC address of network adapter. Since MAC address can be easily spoofed, I need to read the real one which is written on EEPROM. I need to do it using C++ on ...
2
votes
0answers
1k views

Adding multiple gateways for separate physical interfaces with various metrics/priorities

My system has 3 interfaces. These are eth0, eth1 and usb0. eth0 is linked to my router and is the line I want to be used by default. eth1 is un used. usb0 is a 3G phone that's tethered. My issue is ...
2
votes
2answers
581 views

How to disconnect a remote volume in dolphin [closed]

I understand how I can mount a distant volume in Dolphin, through the Network place and the Add Network Folder command, but how can I disconnect from such a remote file system? I want to ensure a ...
5
votes
2answers
575 views

LD_PRELOAD or similar to prevent network access

I'd like to start a program disconnected from the network (because immediately upon starting it tries to download huge amounts of data, which can be prevented by changing settings as soon as it ...
0
votes
2answers
2k views

Unix: How to Test Ip Address is resolved to name

Unix: How to Test ip Address is resolved to name. I need to check whether ip address can be resolved to name using DNS entry via shell script. Code: DNS_Lookup() { LOOKUP=$(nslookup $1) ...
2
votes
3answers
19k views

OpenVPN - Socket bind failed on local address [AF_INET] IP:1194: Cannot assign requested address

How get it resolved? I am trying to start the openVPN server so that i can login remotely using username: demo and password: demo, but openVPN server is failing to start. What am i doing wrong, how ...
2
votes
1answer
403 views

How do I test the performance of my Wifi access point?

I have a home wifi access point consisting of a small Intel board with Atom CPU, 4 GB of memory and a PCI wifi card. Everything works fine, only that I experience major lags during playing of computer ...
1
vote
2answers
473 views

VNC connection taking a long time to connect (essentially…never)

I have my Ubuntu 13.10 desktop with vnc setup and installed. I'm using both a Macbook's integrated vnc remote desktop program and Windows 7's built-in Remote Desktop program to vnc. Both give the same ...
1
vote
1answer
132 views

Unstable network on integrated Debian environment

Good afternoon, I recently installed Debian Wheezy (7.0) on a freescale board (SABRE MCIMX6Q / iMX6Q) and discovered some disturbing lags for all network communications. What I have tried so far was ...
0
votes
1answer
514 views

How to get switch MAC address if it's a layer2 one?

arp -a doesn't show it. How can I get the MAC of it then? (on ex.: from a Linux)
2
votes
0answers
25 views

Route a particular process over another gateway [duplicate]

I have 2 internet connections on differnet interfaces. I have eth0 which is internal ip of 192.168.1.70 and then I have another network connection to a different network which is on wlan0 ...
6
votes
1answer
2k views

Can VirtualBox return IP address for launched VM?

I would like to start my VM from the command line and without the GUI using the following command: VBoxManage startvm <MY_VM> --type headless and the SSH into it from the next prompt. The ...
1
vote
2answers
1k views

Clone hard disk while PXE booting

I would like to boot a PC from the network (e.g., PXE), then let the PC clone its hard disk from an image located on a server, then boot from the hard disk. Is it possible? FAI (fully automatic ...
2
votes
2answers
1k views

make permanent virtual interface?

I want to have two IPs sharing the same interface and it's just working fine by creating a virtual interface using the following command (eth0 is my original interface): ifconfig eth0:0 ...
1
vote
0answers
64 views

Courier-MTA not listening, how to increase debugging information?

i Follow tutorial from https://wiki.archlinux.org/index.php/Courier_MTA based on systemctl status command, the server is working fine # systemctl status courier courier.service - Courier Daemon ...
2
votes
3answers
37k views

Method to check connectivity to other server

I want to check connectivity between 2 servers (i.e. if ssh will succeed). The main idea is to check the shortest way between server-a and server-b using a list of middle servers (for example if I'm ...
2
votes
1answer
54 views

IPTABLES chain need help for restriction

I have two network cards eth0:- 172.16.91.70 (External Zone) eth1:- 172.16.85.70 (Internal Zone) I have clients in my Internal Zone which can access the external network. The ping goes fine and can ...
0
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2answers
2k views

Need to add virtual interface in Suse Enterprise Server edition permanently

How can I add virtual interface in SUSE Linux Enterprise Server 11 permanently?
1
vote
1answer
5k views

How do I generate an SNMP community string for MRTG?

I have trying to set up MRTG on my server, following this guide: https://help.ubuntu.com/community/MRTG I followed it as far as, cfgmaker ...
1
vote
1answer
683 views

Difference between virtual interfaces with ifconfig and iproute2

I am wondering what is the difference between: # ifconfig eth0:0 1.1.1.1/24 and just # ip addr add 1.1.1.1/24 dev eth0 Btw I cannot do # ip addr add 1.1.1.1/24 dev eth0:0 RTNETLINK answers: ...
0
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0answers
71 views

Ping wireless interface from wired interface

I'm performing some wireless measurements. The setup I'm now using is composed of a WiFi AP and two laptops. One laptop (A) and the AP are connected to a common switch, while the second laptop (B) ...
5
votes
3answers
2k views

How to test the quality of my network connection for VoIP services

Sometimes when using VoIP I experience disruptions. I would like to check if the problems could be caused by my internet provider. How could I best test the quality of my bandwidth (throughput and ...
2
votes
2answers
4k views

Manual configuring network interfaces on Cubieboard

I have installed Cubian (It's Debian for the Cubieboard). After the system has started, the wired network works fine. I've read this and configured the network interface(I added only the wlan0 ...
2
votes
1answer
265 views

Linux GUI to track connections made from/to this computer

Is there a GUI to track any socket connection sent to this computer and which program that initiates it? Also if possible track any incoming connection sent to this computer and which program that ...
22
votes
2answers
10k views

Is there an easy way to programmatically extract IP address?

Is there an easy way to programmatically extract IP address, without tedious parsing of ifconfig? I would not mind simple command output processing using sed to do it but not processing multiline ...
2
votes
0answers
426 views

Mint changes default route when eth0 comes back and breaks existing tcp connections

I have two interfaces on my laptop (eth0, wlan0). lets say I am moving away from desk and connecting to an internal network A using openvpn software which uses wlan0 as gateway. I then ssh to a few ...
1
vote
2answers
437 views

IP packets have wrong source address

I have two 4g modems connecting to a network and sending and receiving data. There is a problem though, as the modems keep getting kicked off the network because the source IP address of the packets ...
6
votes
1answer
613 views

Is “zero-copy networking” implemented by default on Linux?

I saw this article: http://lwn.net/2001/0419/kernel.php3 Zero-copy networking will be in 2.4.4. This patch, by David Miller, Alexey Kuznetsov, and others, has been in development and testing ...
1
vote
2answers
119 views

Can an arbitrary process read data coming to/from a network port? How?

For example, postgres does the following as shown with lsof -i: COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME postgres 29200 postgres 8u IPv6 470362 0t0 UDP ...
4
votes
1answer
269 views

Strange ping behavior

I built a linux distribution using the Yocto Project, with little customization. It runs on a Single Board Computer. When I ping this machine, I get the following result: PING 10.128.11.1 ...
1
vote
1answer
1k views

How to set up a “child” proxy that doesn't need a “parent” proxy

I run Linux on a laptop that is sometimes on a corporate network which uses an NTLM proxy server, and thus I have cntlmd running on the laptop as a child proxy to connect to the parent (corporate) ...
20
votes
4answers
31k views

Can I create a virtual ethernet interface named eth0?

I am running Arch based on the Linux 3.10.5-1 kernel. The system uses the new de-facto naming conventions of ethernet interfaces enp*s* and wlp* etc. This is a problem however, as my educational ...
1
vote
3answers
6k views

Cannot connect to internet in Fedora 19

I am brand new to linux and am unable to connect to the internet in Fedora 19. When I type ifconfig I get: lo: flags=73 mtu 65536 inet 127.0.0.1 netmask 255.0.0.0 inet6 ::1 ...
1
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0answers
562 views

wpa_supplicant connection issue: iw dev wlan1 link shows connection, but network unreachable

I've been testing a Wifi card in my machine and I can't seem to get it to connect to my home router. The card is a ralink rt37, I compiled the modules that I needed into the kernel and downloaded a ...
1
vote
1answer
248 views

Redirecting all IP over USB traffic to a fixed address

I'ma bit of a network newbie, so apologies for the inaccurate vocabulary. Say I have a device connected by IP over USB to my computer (running Ubuntu), that connects to 10.0.0.1. I configured my ...
3
votes
3answers
3k views

No route to host after upgrade to Fedora 19

I recently upgraded a system from Fedora 17 to 19. Now, I am not able to connect to any service other than ssh (perhaps a few others may be available but not sure) on it. Earlier this was not a ...
3
votes
3answers
257 views

How to host a website on personal computer

I want to start hosting my website at my own computer as well websites of my friends too (say mini hosting platform). I learned Debian, Bind9 and Apache for this purpose. On my system everything is ...
1
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0answers
304 views

How to set up network for Ekiga on Arch Linux?

I've got two machines with identical Ekiga versions and settings (including accounts), both behind the same router. Both have contacts referencing myself and the standard call back test. Machine A: ...
16
votes
3answers
18k views

Can one ping a NIC by MAC

I have an NIC card on a Debian machine somewhere. The machine is turned off, but I need to know whether the NIC card is turned on so that I can send a wake-on-lan magic packet later (from another ...
0
votes
2answers
201 views

How to attach my domain with bind in real www

How to attach my domain with bind in real wwwI install bind9, with apache. By God's very grace every thing went smooth. my dig, host, nslookup and ping provide this info: my system ip address: ...
10
votes
2answers
4k views

Why does Linux require moving IP from eth interface to bridge interface

When a network interface (e.g., eth0) is added to a Linux bridge (e.g., br0), the IP address must be removed from eth0 and added to br0 for the networking to function properly. I recall reading in ...
1
vote
1answer
98 views

Cannot access ubuntu server from other machines other than the machine which is hosting the virtual machine which is my ubuntu server [closed]

I created a ubuntu server on vmware. I am using it as a file server. I can access it if I am connecting through the machine which hosts the virtual machine. I am not able to do it from other machines ...
7
votes
2answers
546 views

Strange temporary network outage in Linux

I'm facing a very annoying problem that I noticed a week from now and for which I can't find an answer: my network suddenly stops responding, usually coming back exactly 25 seconds later. I was using ...
1
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0answers
147 views

AR9485 Wireless Network Adapter with Linux

Lately I change my VivoBook 500ca for Linux. I installed the latest Mint Cinnamon. I have been having some problems with my wireless card : description: Wireless interface product: AR9485 ...
2
votes
1answer
259 views

about route table setting, and ssh between vmware

firstly i got 2 physical machines PC and notebook 1. under PC(WIN7, 192.168.1.2) have a VMWARE, VMWARE installed one solaris(172.168.1.50). I can use putty to access to solaris from PC. ...