Managing and using network connectivity on a unix system

learn more… | top users | synonyms (1)

3
votes
1answer
64 views

kernel martian source to and from same IP

We are intermittently seeing kernel: martian source log entries for eth0 on a couple of our servers. The interesting thing is that they are to and from the same IP. For instance: Nov 4 02:20:27 ...
13
votes
3answers
24k views

Can't ifdown eth0 (main interface)

I can't ifdown an interface on a Debian 6.0.5 box; user@box:/etc/network$ sudo ifdown eth0 && sudo ifup eth0 ifdown: interface eth0 not configured SIOCADDRT: File exists Failed to bring up ...
24
votes
4answers
30k views

What DNS servers am I using?

How can I check which DNS server am I using (in Linux)? I am using network manager and a wired connection to my university's LAN. (I am trying to find out why my domain doesn't get resolved)
3
votes
2answers
48 views

Should /etc/hosts contain the domain name or the FQDN?

If I want to add an entry to /etc/hosts to resolve all traffic for example.com to 1.2.3.4, do I need to add 1.2.3.4 example.com 1.2.3.4 www.example.com 1.2.3.4 smtp.example.com 1.2.3.4 ...
1
vote
1answer
35 views

Relay server for generic TCP traffic?

Here's my situation: I have a computer (Mac) on a school network that I want to port forward TCP 5222 to for ejabberd, but of course I can't. I have a server at home (Mac with FreeBSD VM) that I can ...
1
vote
1answer
23 views

U-boot static IP doesn't seem to “apply”

When I enter the command setenv ippaddr xxxx.xxxx.xxxx.xxxx it doesn't seem to actually connect to the network on that address. I have a private network set up with the address in the same subnet ...
1
vote
1answer
55 views

Cannot install Intel NIC in Debian squeeze

I've upgraded an old machine to a brand new i3 (Asus H97-PRO motherboard, cpu and ram only) and Debian accepted it quite well, except for the network card. I'm having some trouble trying to install ...
2
votes
1answer
53 views

How to kill processes using a network interface

The issue I'm having is that whenever I just remove my USB wifi card, it kernel panics and reboots the system. Is there some way to detect and kill any processes using the wifi card automatically to ...
2
votes
2answers
81 views

How can I use avahi without a network connection?

How can I test software that uses avahi while my laptop is disconnected from any router? All of the services run on the same machine, so Avahi would be advertising an IP address of 127.0.0.1 for all ...
1
vote
1answer
46 views

Can I add to Linux's privileged ports?

Ports under ~1000 are privileged in Linux. That is to say only root can bind them. There are various reasons, amongst them security: You know that whatever binds one of these ports had root (or ...
2
votes
2answers
101 views

Understanding hostnames

I was recently setting up an MTA on a VPS, and while configuring it I realized I’m quite confused about the concept and implementation of hostnames in Unix. I have a solid understanding of the DNS, ...
1
vote
0answers
25 views

Run two interfaces on one network card

Is it possible to run two different network interfaces (e.g. being connected to two different wlan-networks) on one card in parallel on linux? If yes, how? If no, why not (I would be glad about a bit ...
0
votes
0answers
51 views

connected to ethernet and wifi, “route” browser's connection to wifi only

Sometimes, in my company, I have to work with a different network (through ethernet) that has no internet. On the other hand, I do have access to out Wifi, which has internet. Since I have to spend a ...
3
votes
0answers
28 views

Xen domU sort of ignores /etc/network/interfaces

I have a Debian based Linux installation, that gets around: It started out on a physical system, then I moved the OS into a VMware container and then into a Xen container. As physical and VMware ...
0
votes
0answers
26 views

How can I compile and run a program designed for an older kernel version (2.6) in a newer kernel (3.16)?

I'm trying to run a driver for a network card, but it only supports kernels up to 2.6.32. I need to be able to use this piece of hardware to connect to the Internet. The device I'm using is "VIA ...
7
votes
4answers
13k views

Reverse DNS lookups slowing down network operations on LAN

Environment My LAN setup is quite basic: A router connected to the ISP's modem and the internet My development pc directly connected to the router The router provides DHCP but does not run its ...
0
votes
1answer
47 views

Can't use hostname for my linux machine

I installed apache on my RHEL machine yesterday and found I could access it from a browser using http://. Of course, sshing using the hostname was also working. So, I made an index.html file inside ...
1
vote
0answers
70 views

Setting up a 802.11s mesh network for mobile devices to communicate with a wired server

I'm in the process of developing an android app that maintains a device's connectivity to a linux-based WiFi mesh network, and periodically sends status information (GPS, battery life, etc.) to a ...
1
vote
1answer
26 views

Start a service on a network request (socket activation)

I have a program that under normal activation listens on some port. I don't want the program running continuously. Is there a "quick and dirty" way to wrap the application in a shell script or ...
1
vote
0answers
72 views

How to reach interface alias bond0

I'am setting up an interface alias with my bond0 network. Why am I not able to ping/reach the second ip address, in this case 192.168.30.84? However I can ping the address from another server. ~# ...
11
votes
3answers
20k views

VirtualBox: two network interfaces (NAT and host-only ones) in a Debian guest on Ubuntu

I created a Debian VM on VirtualBox with two interfaces: a NAT one (for accessing internet) and a host-only one. However, I do not know how to make both interfaces work at the same time. If I the ...
15
votes
11answers
55k views

Cannot enable network after CentOS 6.3 fresh install

I am trying to perform a fresh CentOS 6.3 installation then run various yum commands such as yum install httpd. The installation runs fine, however I cannot run any network based commands like yum I ...
3
votes
0answers
33 views

Workstation-like environment across Debian clients

At our university we have a workstation-like system. It's windows XP (or Win-7 on some machines) and you can sit to any computer and log in with your credentials. It seems to be pulling some of your ...
5
votes
2answers
76 views

Is there an ICMP echo request service?

Often, in applications that I develop, I like to include a network status indicator for various devices on the network. The easiest way to monitor these devices is by pinging them. But ICMP echoes are ...
0
votes
0answers
16 views

What is the functional difference between wpa_supplicant and the system's /etc/networks/interfaces file?

I understand that one is a program and that one is a configuration file used by linux, but practically what is the function of each of these pieces in conjunction with my computer's network ...
1
vote
0answers
65 views

Connect to IPsec VPN using OpenSwan

I'm connected to Internet with a simple ADSL router with NAT. I have a smartphone and a laptop running linux. I need to connect to a IPsec server using OpenSwan. First I tested that it is possible to ...
1
vote
1answer
51 views

tcpdump won't capture entire packet

I'm using sudo tcpdump -A -s0 -ien0 port 80 | grep schemas-microsoft >> ~/Downloads/convert.txt to capture microsoft-schema xmls being sent throught the internet, when tcpdump is supposed to ...
2
votes
2answers
1k views

Redirect the default HTTP port to an application

On my CentOS server at mydomain.com, I have an svn web application running on port 8880. I want to hide the port: at this moment, if anybody wants to access, they need to access through ...
1
vote
1answer
67 views

Reverse DNS PTR lookups ocurring on each connection

I'm running a Debian-based VPS (Linux vps 2.6.32-042stab092.3 #1 SMP Sun Jul 20 13:27:24 MSK 2014 x86_64 GNU/Linux) which is behaving a bit strange. Whenever a new connection is established to it, it ...
0
votes
1answer
18 views

Fedora does not load some sites in home network

Since I switched from Windows 8.1 to Fedora 20 (my first time Linux experience) I have problems in my home network. When I surf from the office with the notebook, every site loads fine. As soon as ...
2
votes
1answer
49 views

How to do mac spoofing on Linux Mint 17?

How to do mac spoofing on Linux Mint 17? Through macchanger -a I've tried to changemy mac address but new mac id doesn't authenticates successfully. pppd gives successful authentication message only ...
2
votes
2answers
67 views

How to find out how many TCP retransmits are occurring?

I am running Debian Wheezy on an ARMHF platform and do most of the communications over fairly unreliable cell phone networks. Is there a way to read the no. of re-transmits the TCP stack has done ...
1
vote
1answer
69 views

Allow multicast packages from the bridge to wire in KVM

On a CentOS 6.5 host, I have a couple of guests - Ubuntu 12.04 and CentOS 6.5. The Ubuntu guest is generating mcast traffic that is visible via a tcpdump on the br3 interface. It is also visible on ...
0
votes
0answers
28 views

route -n gives output “route: fscanf”

If I boot my system and no interface has an IP address I get the above output. However if I give an interface an IP, even if I remove it again, this will disappear. Why does this happen? Is it that ...
1
vote
1answer
14 views

How to apply a parameter to packet so TC can prioritize\classify it

I want to add a parameter to the packet so that I can later let TC (HTB in specific) prioritize my packet (based on filtering that parameter). I thought about filtering by socket but as I understand ...
2
votes
2answers
2k views

Guest OS Ubuntu 12.04 no network connection

Recently added a new *.VDI image with Ubuntu 12.04 to my existing VirtualBox. The machine hangs with a "Waiting for network configuration" error, eventually times out after 60 seconds and boots in ...
0
votes
1answer
70 views

Getting all IPs of devices connected to the same router

I have several linux devices connected to the same router (of which I am not a administrator). How can I find out the ip addresses of all other devices by executing some commands in one of them?
1
vote
0answers
42 views

How do I write the rule that has an edge server forward a clients request to an internal network server and back?

I have a network situation as follows: -server1:1.1.1.1 -server2:2.2.2.2 -tunnel 10.8.0.0/24 -client: 3.3.3.3 I'm trying to have client IP 3.3.3.3 do an HTTP request from the 1.1.1.1 server. ...
0
votes
1answer
56 views

Isolate subnets on the same interface

I need to isolate Subnets on a linux machine CentOS that act as gateway. I have the following scenario. CentOS eth0 pub ip addres eth0.1 192.168.1.1 eth0.2 192.168.2.1 Now eth0.1 and eth0.2 can ...
5
votes
2answers
116 views

How to check programatically if the Ethernet cable is plugged in?

As you know, in Windows, when we plug in the network cable, the network symbol will change to another status. How can I know whether the cable is plugged in or not via the command prompt in Linux?
8
votes
3answers
4k views

How do I get to use .local hostnames with Arch Linux?

If I'm using Ubuntu or Linux Mint (the only two flavours I've tried and know work for sure), I can run something like this: wayne@myhost$ ssh wayne@otherhost.local And the name is automagically ...
3
votes
0answers
60 views

Create virtual network adapter with own MAC and IP?

I have a server with 4 different IPs over one real NIC. Now i try to setup different virtual network adapter in debian with this IPs. The Problem is, that each IP needs also a specific MAC. Otherwise ...
2
votes
2answers
2k views

Multicast UDP not working

Multicast UDP on raspberry pi I haven't narrowed things down enough to know if my issue is because of debian, raspbian specifically, or if I am just missing a something completely. I have a python ...
4
votes
2answers
203 views

Why is ping much faster when using -f

I'm pinging the same host from the same machine at the same time. And when using -f, the result is almost twice as good: [root@localhost Desktop]# ping 196.1.6.16 PING 196.1.6.16 (196.1.6.16) 56(84) ...
2
votes
1answer
386 views

Check for plugged in network cable on startup

I actually wanted to post the below as an answer to this question titled: ifup eth0 timeout during boot. But am not sure if this is right approach or it's a way of screwing up things badly. We can ...
1
vote
0answers
76 views

TCPDump To Capture A Tracepath6 Datagram

I'm trying to use TCPDump to capture an IPv6 datagram using: tcpdump -c 1 -i eth1 -vvvs0 ip6 and dst host H2.net2 & tracepath6 H2.net2 I'm running this script on H1.net1; R12.net1 is the ...
1
vote
0answers
26 views

NAT-T set up using 3 linux machines

I am trying to have a simple NAT-T setup using 3 linux machines. Linux1 Linux2(NATdevice) Linux3 (eth0) 192.168.1.51 <--->(eth1)192.168.1.80 & ...
1
vote
1answer
270 views

Networking issue in IBM x3650 after install Ubuntu 14.04.1

I have a problem making TCP connections after a fresh Ubuntu 14.04 installation. First of all, after booting the interface is always off. In my case the interface is manually configured and named em2. ...
1
vote
0answers
61 views

How to populate /etc/network/interfaces automatically

I am trying to populate /etc/network/interfaces with a dhcp config for all interfaces at the first system boot (Debian 7.6 server). I modified the script in : /lib/udev/write_net_rules by adding: ...
0
votes
2answers
22 views

net cat client and server model

I tried to make server client model as below on one shell nc -l -p 8080 this works as a server and on another nc 127.0.0.1 8080 and this works as a client all of this is fine ... the ...