IP stands for "Internet Protocol". It is one of the fundamental protocols that powers the internet. IP is how data is able to be routed to the correct destination - your computer is assigned an IP address, and when you need to get data back, that data gets sent to your IP address.

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tcpdump command works only on local ip

I am trying to capture some IP packets in my personal LAN with tcpdump, through the command tcpdump -A -i eth0 'tcp and (((ip[2:2] - ((ip[0]&0xf)<<2)) - ((tcp[12]&0xf0)>>2)) != 0) ...
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129 views

On ssh connection the auth.log shows as source IP the external IP of the server instead of the IP of the client

I have a very odd situation with my ssh connection. Every time I connect to my server, whatever is my external ip, the connection have as source the server's external ip. Example Server S.O.: ...
0
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1answer
49 views

IP Prefix - how do I declare this?

Hi I have an IP Prefix issue I would like to declare the following IP's as "safe" using ip prefix "methodology" ("?") The IP's first three parts of the IP have been doctored to protect the innocent, ...
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0answers
55 views

Linux Source Routing with one gateway

I've a Linux box which have IP 10.1.1.100/24 on eth0 with gateway 10.1.1.1 and as well as 20.1.1.1 on eth0:1 and 20.1.1.2 on eth0:2 . Is there any way that I could communicate to a remote machine ...
10
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1answer
501 views

Is it better to set -j REJECT or -j DROP in iptables?

There's an example of iptables rules on archlinux wiki: # Generated by iptables-save v1.4.18 on Sun Mar 17 14:21:12 2013 *filter :INPUT DROP [0:0] :FORWARD DROP [0:0] :OUTPUT ACCEPT [0:0] :TCP - ...
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3answers
2k views

Why can't I ping Google?

I can't ping google.com (unknown host). But I can ping IP addresses. I tried to ping the IP address of Google but it doesn't work. resolv.conf nameserver 8.8.8.8 nameserver 209.139.209.33 ...
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2answers
2k views

Hostname and IP address mapping in /etc/hosts

In my linux machine, when I run hostname, it shows mongodb, but when I run host mongodb, it shows: mongodb@mongodb:/var/hadoop/hadoop-1.2.1/bin$ host mongodb Host mongodb not found: 2(SERVFAIL) My ...
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1answer
135 views

how to check if the kernel support for ip alias?

it surprisingly that I get no explicit results when I googled "kernel ip alias support", and I have looked up the linux network administrator, 3rd edition, it says: check that you have a ...
0
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1answer
56 views

host only ip address: can it be 10.*.*.*?

My router is set to have computers IP range from 10.1.1.1 to 10.1.1.60 I'm trying to run Linux in virtual box in a host computer with windows 7. The host computer has 10.1.1.5 currently, which is ...
2
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2answers
193 views

SSH access from inside and outside a LAN using the same terminal command

I have a Raspberry Pi (RPi) and I am making remote connections to it using ssh. I have managed to set up ssh correctly such that I can access the RPi both from a local area network and from the ...
0
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1answer
40 views

ssh login after changed IP

I have server running Ubuntu 12.04.2 LTS (GNU/Linux 2.6.32-042stab078.28 i686) Had no problem logging in to the server via ssh until my Internet Provider changed my IP. Now, the server keeps adding ...
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2answers
676 views

Finding the PID of the process using a specific port?

I am installing hadoop on my Ubuntu system. When I start it, it reports that port 9000 is busy. I used netstat -nlp|grep 9000 to see if such a port exists and I got this: tcp 0 0 ...
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0answers
93 views

Debian access point is detected, but provides no Internet access

I am use Debian sid. I want to share my network (ppp0) via AP (Access Point) to my mobile device. This is my configuration. /etc/hostapd/hostapd.conf : # WiFi Hotspot interface=wlan0 driver=nl80211 ...
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1answer
246 views
+50

Send a packet over the network even when its target is the local host

Under Linux if you send a packet to the address of one of its network interfaces, this packet is routed internally, it is never sent over the network. That's the right thing in 99.99% of the cases. ...
0
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2answers
266 views

Connecting to localhost via system IP address

I am using Linux Mint 15, and I am running a Ruby web server(Thin) on port 3000. I can connect from my machine via localhost:3000, but the moment I type in the system IP address (eg. ...
3
votes
1answer
87 views

Using shell script to select static IPv4 configuration according to router address

I have Linux Mint 15, I live in a university where the hostel and lab have separate static IP settings. Is there a way to set up the connection mechanism so that my laptop will automatically select ...
2
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2answers
731 views

Static routes in route-eth0 ignored

Why might route-eth0 be ignored but route-eth1 not? Might be because eth0 is using DHCP and eth1 is statically-configured? I have some static routes configured in ...
0
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2answers
401 views

Need IP for my Virtual Machine

I want to scp to my virtual machine (CentOS 6) from my Windows 8 machine. I have installed VMPlayer and installed CentOS 6 on my machine. I have enabled Bridged adapter setting, but I still can't see ...
0
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1answer
802 views

Is there any IP messenger for Linux (CentOS)?

Currently am using a Linux (CentOS) machine. Is there any IP messenger for CentOS like iptux and Gnome IP Messenger?
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2answers
216 views

Static IP for 2 PCs on crossover cable in interfaces(5) file?

I've got 2 PCs connected on an Ethernet crossover cable. On PC1 I run: sudo ip addr add 192.168.2.1 peer 192.168.2.2 dev eth0 sudo ip link set dev eth0 up On PC2 I run: sudo ip addr add ...
0
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1answer
115 views

Current IP address as visible from the internet? [duplicate]

I know I can get the locally assigned IP address of my current machine by the local router like so: ifconfig However, I want to know what my IP address is as visible from the outside world. Or, in ...
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2answers
528 views

How does ifconfig find a machine's external IP address?

Normally when I want to check the external IP address of a given machine, I simply curl some external website that sends me a response telling me what my IP address appears to it. However, I've ...
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2answers
88 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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2answers
1k 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 ...
1
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1answer
110 views

How to resolve when the IP of a NFS server changes

I have a Windows NFS server and several CentOS linux servers which were mounting volumes from it. The Windows server moved to a new network and even though DNS works and the NFS mount was mounted by ...
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0answers
57 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 ...
2
votes
1answer
4k 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 ...
3
votes
1answer
6k 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 ...
0
votes
1answer
46 views

Ip connectivity with two interfcaes

I have two network interfaces in Linux machine , eth0 and eth1. IP is assigned to both interface from two different VLANs and default gateway to eth0. Now if interface eth0 is down I am unable to ...
0
votes
3answers
94 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, ...
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3answers
445 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 ...
0
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2answers
178 views

I want a static IP address for my (network? or computer?)

Me and two friends have been making a video game. We've thought about download hosting a bit, but found that Mediafire, Box, and those sorts of file-hosting sites' maximum free file-upload size is far ...
3
votes
2answers
345 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: ...
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2answers
190 views

Resolving pseudo domain name to private IP

Assume I have a VM running on OSX with private IP 10.0.0.1 which can be accessed from the host machine. I was wondering how can I map a pseudo domain, *.app.dev, to the private IP on my host machine ...
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3answers
229 views

Is there any alternative to echo daemon to display ip?

Is there any alternative to echo daemon to display ip instead of given string? For ex: my ip = 80.1.2.3 server ip = 1.2.3.4 root@my-machine bash$ telnet 1.2.3.4 Trying 1.2.3.4... Connected to ...
2
votes
2answers
1k views

What does ifup do when “/etc/network/interfaces” has an invalid netmask address?

The interfaces file looks like below: auto lo iface lo inet loopback auto eth0 iface eth0 inet static address 192.168.0.130 netmask 250.255.255.0 gateway 192.168.0.254 As you can see ...
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183 views

Share (masquerade) Internet connection from Debian desktop to a bunch of computers

I need to share the Internet connection of my Debian desktop to some other devices (a Mac Laptop, and an Android tablet). The Debian desktop is connected to the local network via eth0, and the rest ...
0
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0answers
55 views

When adding a ip via ifcfg how do you have it auto increment the clonenum?

I'm writing a script that adds ips to a multihomed machine. I'm not allowed to use network-scripts folder because well that's what they said. They also stated they wanted to clone num to increase. ...
2
votes
1answer
109 views

Share an external IP with several virtual hosts

For a centos server hosting a few LAMP virtual machines (using VirtualBox), I have a single external IP. I would like to be able to use this single host external IP to address the virtual machines. ...
1
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0answers
111 views

SSH to a machine that is getting it's network connection from an Android device(Google TV)

I have a Linux(Ubuntu) machine for my HTPC. It's running XBMC and I control it via my IR remote control. I don't have a (wired) keyboard to control it. It has Wifi adaptor but it's not installed. I ...
1
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1answer
45 views

Reach service on VM with private address

I have this configuration: source: https://www.lucidchart.com/publicSegments/view/5256a1e5-afb0-4c7a-96fa-35750a00527d/image.png Basically, I have to reach a service which is running on the virtual ...
4
votes
3answers
1k views

Difference between 'ifconfig' and 'ip' commands

I read some articles/tutorials on 'ifconfig' command, most of them included a common statement - "ifconfig is deprecated by ip command" and suggested to learn ip command. But none of them ...
2
votes
2answers
375 views

keep losing IP with dhcpcd

I have an Arch Linux install in a VirtualBox VM, and as I'm working all of a sudden, it will lose it's dynamic IP address. When this happens, if I check on the status of the dhcpcd service it says ...
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votes
2answers
1k 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 ...
3
votes
2answers
734 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 ...
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2answers
2k views

binding ip address to hostname

I just registered a domain name and paid for hosting with CentOS and I found that I had to do the binding myself following the lengthy steps http://www.linux-sxs.org/internet_serving/bind9.html I was ...
2
votes
1answer
595 views

Environment variable for ip address

I see somewhere people use: IF_ADDRESS="$(echo "$IP4_ADDRESS_0" | cut -d'/' -f1)" to get the IP address in a network configuration script. In my system, I create a script under the directory ...
4
votes
1answer
885 views

Can't ssh to beaglebone?

After I did: route add default gw 192.168.7.1 I also changed /etc/resolv.conf: nameserver 192.168.7.1 in order to share internet between Ubuntu in VMware. I've got internet working but after a ...
2
votes
1answer
376 views

What is the simplest way to connect to wireless on a Debian system with nothing but essential?

I have a Debian Jessie system which, for reasons unrelated to this question, has nothing installed but the set of essential system packages. What is the simplest method for connecting to a wireless ...
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vote
2answers
975 views

Get my country by IP in bash

I want to use the name of the country where I am now in a bash script. I can get the external IP using next command: curl ifconfig.me But how can I get my country name?