Managing and using network connectivity on a unix system

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8
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2answers
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escape characters in /etc/network/interfaces

I want to be sure that whatever string I pass into the line wpa-ssid "abc" in /etc/network/interfaces won't be used to break out of the configuration. All I can find in the manual is that \ can be ...
1
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2answers
3k views

I am trying to open port 19132 on my Ubuntu server, but not working

I am trying to set up a server for my son to play Pocketmine. This is a PHP server and it is running on port 19132. I have opened this port on my router and if I run another server, like a Rails ...
5
votes
1answer
11k views

Firefox: use system proxy settings, but where are these?

Running Ubuntu 13.10, Firefox is configured to use the system proxy settings, but it seems it fails to pick them up. The computer is connected to the network, and it's possible to establish a ...
0
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0answers
1k views

Debian bridge doesn't accept IPv6 config

I'm currently trying to configure my bridge in Debian 7. I do have a working config for IPv4: auto eth0 iface eth0 inet manual auto br0 iface br0 inet static address xx.xx.xx.131 netmask ...
0
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1answer
148 views

why gentoo livecd can not detect the linked network card?

The original os is Ubuntu 12.04, machine has 4 network cards, and the first netcard is linked. If use ethtool, will get Link detected: yes. When I use gentoo livecd to start, and config network, I ...
1
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1answer
45 views

Measure time to get DHCP address?

Is there any tool or way to measure how much time your DHCP router needs to give you IP address? I'm sure that there is something, as it's pretty important when debugging network.
2
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1answer
140 views

Port forwarding using iptables on Linux

I want to forward a local port to a remote port (8041) to a port (8042) on a remote machine (10.0.0.42). I can do this via ssh -L 10.0.0.41:8041:10.0.0.42:8042 user@localhost where 10.0.0.41 is ...
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2answers
135 views

how to identify IP address on eth0 when console isn’t available

I need help about the following I have very old Linux server with one IP address, unfortunately I can’t to access to Linux machine VIA console and I not remember the IP address So I now thinking ...
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0answers
222 views

How to make Network alive but speed low, slow for upload, download?

I have own application written (Python, Java) which does upload/download for streaming. Now in my local office network and home network setup i can't simulate slow/low latency network (as a result i ...
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2answers
8k views

Check a range of IP addresses to see if a host is active

I need to write a bash shell script that will check a range of IP addresses to see if a host is “alive” at that address.I also need to list the IP numbers of those that are “alive”, and provide a ...
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0answers
472 views

Debian: Network connection dropping randomly

I am having an issue with my network connection dropping after a while, sometimes an hour if I'm lucky two. I can regain the connection by running: sudo ifdown wlan0 sudo ifup --force wlan0 when I ...
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0answers
108 views

What should be the right dhcp configuration for generating a new network over eth0?

Even not under a real server like scenario, I'm testing with dhcpd for learning and practice purposes. I'm using Ubuntu 12.04 LTS. I want to offer a network by my eth0 interface. I receive ip and so ...
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0answers
81 views

Network connecting trouble shooting

I am trying to connect to the network of my school. With Windows 7 + IE it is not problem at all. I connect to it, no matter what web-page I try to reach, I get forwarded to ...
1
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1answer
504 views

How to calculate Linux Network RX, TX total stats - not just between reboots?

Is there any way to calculate the Linux network interfaces RX , TX for all times? The suggested method mentioned in this Cyberciti article titled: Linux See Ethernet Statistics only returns the stats ...
3
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2answers
13k views

tcp dump outgoing connection packets

What is the command syntax to log all tcp connection packets? I am trying to see what address and ports my computer is trying to connect to outgoing so that I may config my firewall.
5
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2answers
5k views

BIND9 as a DNS server refuses requests

I am trying to set up a DNS server on Amazon Linux using BIND9. It has to act as a master nameserver for a lot of domains. I have imported all of the DNS zone files using NamedManager (a web ...
4
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2answers
20k views

Set Static IP in CentOS 6.4?

Most guides seem to revolve around modifying ifcfg-eth0, which doesn't exist on my system.. [root@Azaz07]# vi /etc/sysconfig/network-scripts/ifcfg-eth0 [root@Azaz07]# ls ...
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2answers
931 views

How to monitor network performance for each application in FreeBSD / PC-BSD?

I'm using a PC-BSD workstation, and I would like to know if there is a way to monitor which app / process is using the network. I use a Mac OS X (Mavericks) laptop, and the "Network" tab in the ...
3
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3answers
4k views

/usr/bin/host not picking up changes to /etc/hosts even after reboot

I have a Ubuntu Server 12.04 (amd64) machine on which, when I change /etc/hosts, the changes aren't picked up, even after a reboot. I am using /usr/bin/host to test, but none of the other programs ...
3
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1answer
257 views

Discover clients connected to a network [duplicate]

How can you discover who is connected to a wifi network near you? (you not being connected to it). I know that some tools can scan your own network, and that some tools like Wireshark can monitor ...
1
vote
1answer
743 views

Wake on LAN through PHY and unicast only works in the first ~30 seconds after pm-suspend

I'm having some trouble with Wake on LAN through PHY and unicast. I'm able to wake the system by pinging or sshing the shut down machine, but only within the first ~30 seconds. Why's that, what could ...
0
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2answers
832 views

Frequent connection aborts with arch-linux

I have an arch-linux system which I use as a server. I try to connect with ssh and samba from different Windows 7 machines. However, I get frequent connection aborts. ssh (e.g. putty or kitty) says ...
4
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1answer
7k views

TCP buffers keep filling up (Recv-Q full): named unresponsive

Using netstat -an, I set the message that the Recv-Q is full. It is filling up to the rmem_max: Active Internet connections (servers and established) Proto Recv-Q Send-Q Local Address ...
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0answers
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 ...
2
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0answers
391 views

iptables REDIRECT in combination with matching on interface vs. IP address

I've successfully set up Tor for transparent proxying using iptables (ie, all outgoing traffic is sent through Tor without the application's knowledge). In doing so, I discovered both an odd problem ...
4
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1answer
371 views

Can I pipe lpt port over tcp?

I'd like to pipe data in and out to a lpt (parallel IEEE 1284) port on another machine, to remotely use a device. Can it be done in a common unix-y system? I have ubuntu 12.04. :) I was thinking ...
1
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1answer
184 views

Can only get one network to be accessible from outside

So here's a quick overview of my setup: I purchased a new Mac Mini server and I am hosting it with a Mac Mini co-lo facility. At first I had them keep OSX installed and I was using VirtualBox to ...
4
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1answer
1k views

how to intercept IP packets on linux

I am trying to achieve this goal on Linux (not sure if it is possible and how if so): I need to write a program to intercept all IP packets on an interface, and deliver this packet to a specific set ...
24
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1answer
61k views

Using ip addr instead of ifconfig reports “RTNETLINK answers: File exists” on Debian

I have a Debian system working as a wireless router with eth0 and wlan0. Now I added an additional network manually on eth1 with ifconfig: alix:~# ifconfig eth1 192.168.0.2 netmask 255.255.255.0 ...
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2answers
449 views

Traffic not being routed through Cisco VPN

I'm unable to use my school's VPN correctly in Linux. This is what I did: Installed a fresh x64 Kali linux (latest). Updated all current packages through apt-get Installed the required vpn ...
25
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2answers
98k views

Sending messages to another user

Is there any command to send messages through the Linux shell to other people on the same network? I'm using write user and then write the message itself. But there's any command that doesn't show my ...
0
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1answer
3k views

virtual box debian guest with nat & host-only adapters: 'No route to host' when trying to access host from guest

I have just set up a Debian guest inside VirtualBox, on a Fedora host. I use two adapters: NAT (internet for the guest, which works fine) and host-only (ssh from host to guest, nfs, etc.). I am able ...
11
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1answer
2k views

how does ping zero works?

can anybody explain how does ping 0 works and it translate to 127.0.0.1. [champu@testsrv ]$ ping 0 PING 0 (127.0.0.1) 56(84) bytes of data. 64 bytes from 127.0.0.1: icmp_seq=1 ttl=64 time=0.039 ms 64 ...
1
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1answer
2k views

Cannot Connect to Internet but can SSH into Solaris x86 (vs. 11)

I am able to connect remotely to the machine using SSH, but I cannot ping www.google.com through the machine. I did the following to make sure SSH was enabled (well I know it is, as I am using ...
1
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1answer
331 views

`cat /dev/ttyACM` loses data when piped through netcat

I'm reading data from /dev/ttyACM0 using cat /dev/ttyACM0 on a Raspberry Pi. The data comes from a device, which sends lines in the form 15.00 1316013 15 where the first number is a value, the ...
0
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3answers
676 views

Why do two Ubuntu systems in the same network behave differently in DNS resolution?

I have two systems, both running Ubuntu 12.04, which are within the same network (connected by hubs without routing logic). Both systems are configured quite similar, but not identical. In particular, ...
2
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1answer
42 views

Ubuntu blocks access to services when not logged in

I'm not really sure what's going on here. I have the following: A fresh install of Ubuntu 12.04 LTS. Jira 6.1.2 installed as per instructions from Atlassian. Confluence 3.5.13 installed as per ...
2
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2answers
3k 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 ...
3
votes
4answers
17k views

TFTP configuration problems

I can not get TFTP to work properly on my system. I have set /etc/default/tftpd-hpa to /srv/tftp/ which I have set to permissions 777 like all the contents as well (and /srv/ too) however, whenever I ...
3
votes
1answer
77 views

Per executable UDP port redirection possible?

I have a black box program which listens on a particular UDP port. I'd like it to listen to a UDP port of my choosing. Is there a way to trick the executable into listening on a differen port. I ...
2
votes
1answer
9k views

hostapd, ath5k, nl80211 - how to get it working?

I have this network adapter in an Asus notebook running Manjaro Linux (based on Arch), everything up to date (Kernel: 3.10.11): > lspci -k | grep -A 3 -i "network" lspci: Unable to load libkmod ...
4
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2answers
9k views

The netcat command can't access an open port

I have two servers over which I am trying to install some software. One is server1(IP 10.1.2.205) and the other is server2(IP 10.1.2.206). Both are able to ping each other by name and by IP address ...
2
votes
3answers
3k views

Programmatically extract private IP address(es)

I'm looking for an easy way to programmatically extract the private IPv4 address(es) of a computer. Something similar to this question, but restricted to private IPs. As an example, I can extract ...
3
votes
1answer
525 views

VLAN setup on CentOS

I have two networks I want to separate from each other (no inter-routing). I'm using a Linux host as a router and I have a Juniper switch as the switch (obviously). My LAN interface on the Linux ...
3
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2answers
832 views

Converting Webserver Logged IP Addresses to DNS

I'm trying to use a bash script to process a webserver log file and replace any IP's it finds with their corresponding DNS hostnames. An example entry of a single line from the log file is: ...
4
votes
1answer
3k views

How to assign an additional IP/hostname to a chrooted environment?

While I can simply have e.g. sshd in a chroot environment ("chrootenv") listen to a different port than its parent ("parentenv"), it would be more convenient to have that environment have an ...
5
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1answer
1k views

getaddrinfo() from shell? [duplicate]

When you call ping name.domain, it goes through both /etc/hosts and the DNS resolver to obtain an IP. It could be an IP hard-coded in /etc/hosts, or it could be one from the DNS server. It does so by ...
5
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2answers
3k views

My Ping command does not seem to ever finish. Does that mean it is suceeeding?

I am pinging a remote IP. I know very little about the Ping command. When I ping the IP, it keeps going and going... I am not using the -t option. Me$ ping 137.30.124.104 PING 137.30.124.104 ...
0
votes
1answer
2k views

Mint 15 on Lenovo G700: wired internet not working (Atheros QCA8172)

Mint 15 doesn't see internet after installing it in dualboot with windows 8 (in Windows internet works well). My network card is Qualcomm Atheros QCA8172 Fast Ethernet (rev 10). What I did: Install ...
3
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2answers
4k views

run a script at shutdown in Debain

I am using Debain wheezy. My problem is , I am using a limited 2.5 GB net connection. My idea is simply running a script as #!/bin/bash date >> ~/mydatausage.txt ifconfig -a >> ...