the IP protocol and IP addresses

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10
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3answers
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Can't access select https sites on Linux over PPPoE

My internet connection used to be a direct LAN connection to my provider. Back then, everything would load fine on both Windows and Ubuntu (dual boot). However, a while ago they started needing me to ...
143
votes
21answers
137k views

How can I get my external IP address in a shell script?

I need to find my external IP address from a shell script. At the moment I use this function: myip () { lwp-request -o text checkip.dyndns.org | awk '{ print $NF }' } But it depends on perl-...
5
votes
3answers
23k views

How can I restart a network interface?

How can I restart a network interface? I have a vm that doesn't update its IP address correctly when switching between home and work. The vm runs Ubuntu server and uses a bridged network adapter.
3
votes
1answer
991 views

Route SSH to host through interface

Is it possible to route all outgoing requests for SSH (port 22) to mydynamicdns.afraid.org via wlan0 instead of eth0 when both are connected? Since my IP is dynamic, I would like to use a name ...
23
votes
2answers
11k 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 ...
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13answers
38k views

How to get my own IP address and save it to a variable in a shell script?

How can I get my own IP address and save it to a variable in a shell script?
9
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2answers
6k views

How to know if a network interface is tap, tun, bridge or physical?

As far as i know, there are 4 main types of network interfaces in linux: tun, tap, bridge and physical. When i'm doing sys admin on machines running KVM, i usually come accross tap, bridge and ...
4
votes
3answers
4k views

Send duplicate packets over two Internet connections

I need to duplicate an RTP stream over two different (non-reliable) Internet connections. On the receiver side, I will probably run a custom program that will use a buffer and rebuild the stream ...
4
votes
1answer
3k views

multigateway routing for specific src port

I have two gateway to access internet, somehow I want to load balancing it, so far its working, but some connection or service need persistent gateway IP to be used, so the client should never change ...
5
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3answers
5k views

How to filter IPv4 and IPv6 addresses?

echo "1.1.1.1" | awk '/[0-9]*\.[0-9]*\.[0-9]*\.[0-9]*/ {print $1}' How can I filter IPv4 addresses in a script, and how can I filter IPv6 addresses. I mean more precisely then this so the oneliner ...
2
votes
1answer
171 views

Get the external IP address in shell without dig in 2016?

This question: "How can I get my external IP address in bash?" Solves the question with a call to dig: dig +short myip.opendns.com @resolver1.opendns.com; that is the fastest resolution possible, ...
10
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3answers
17k views

Find out network traffic per IP

We have one central server which functions as an internet gateway. This server is connected to the internet, and using iptables we forward traffic and share the internet connection among all computers ...
2
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1answer
2k views

Static IP address shifting to 192.168.1.251

I have a system with a static IP address of 192.168.1.150. I configured /etc/network/interfaces manually (i.e. without using NetworkManager.) It is a web server hosting three sites. I am having ...
26
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1answer
30k views

What is kernel ip forwarding?

I have seen on many blogs, using this command to enable IP forwarding while using many network security/sniffing tools on linux echo 1 > /proc/sys/net/ipv4/ip_forward Can anyone explain me in ...
20
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1answer
11k 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 - [0:0]...
55
votes
2answers
8k views

How does SSH connection survive a network restart?

From a Linux SSH shell, type /etc/init.d/network restart to restart the network service. I expect my SSH connection to die since the network service goes down. But it doesn't. Very cool. But how does ...
4
votes
2answers
21k 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 /etc/sysconfig/network-...
19
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3answers
7k views

IP to Country console command

Is there a console command that takes an IP address as an input and shows its geographical information like city, country, ISP, etc.?
8
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3answers
6k 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 ...
5
votes
2answers
4k views

Routing for multiple uplinks/providers

I have a PC with two internet connections. The first one is an Ethernet interface to connect to my local network and access internet via my router. The second one use a GSM modem to connect with ppp. ...
9
votes
1answer
1k views

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. ...
6
votes
2answers
1k 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 192.168.2....
6
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2answers
10k views

Discover MTU between me and destination IP

In a case I can use only UDP and ICMP protocols, how can I discover, in bytes, the path MTU for packet transfer from my computer to a destination IP?
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votes
2answers
5k views

Can't ping broadcast

We're running four computers connected to a hub (yes a hub not a switch) on Fedora 13. They were installed using images from a colleague that has recently left us to go back to school, they may have ...
7
votes
2answers
2k views

SSH session through OpenVPN cuts off / locks up after a few lines

I have a large number of identical fanless PCs running debian 6 (ARM). Most of these are connected via comcast and work ok. There are some that are connected to 'WiMax' modems and are having ...
4
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1answer
1k views

Why is this static route not taking effect?

Original Question I am running Ubuntu and network manager. I have two different interfaces, eth0 and eth1. Network manager has (as far as I can tell) correctly added this manual route: ~$ ip route ...
6
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3answers
156 views

Is it possible to initiate an IP connection between two NICs in same PC externally?

If two NICs in a Linux machine are directly connected with each other using an external cable, then is it possible to initiate an IP connection between those two NICs over this cable? I configured my ...
3
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2answers
82 views

How to track my public IP address in a log file?

I'd like to save my public IP address to a log file so I can use them to exclude my own visit to my websites in the stats collections. At the moment I can see my actual public IP address--whatsmyip....
3
votes
0answers
113 views

delay in IP route deletion

(Apologies if this is the wrong StackExchange for this question, but there does seem to be some confusion regarding appropriate targeting of IP networking questions) I am very much a network newbie, ...
3
votes
2answers
871 views

Bash: Permission denied when trying to echo data directly to Network

I am trying to send characters directly to the network stack as explained in this thread. Even when the process work OK under CygWin (Windows), the same lines do fail on Ubuntu v14.04: luis@...
2
votes
1answer
947 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 /proc/...
2
votes
1answer
140 views

If I use an SSH tunnel to forward a remote port to a local one, and my IP address changes, will that tunnel still work?

Simple - trying to use my personal computer as a server, by forwarding a public static IP address's port to mine, but I'm worried about Comcast pulling out the rug from underneath my feet and changing ...
1
vote
1answer
612 views

Unable to get embedded device to ping anything on the network

I have an embedded device, built using buildroot, kernel version 3.6.11 running busybox. The kernel is built with completely default options. I have configured the device according to what the network ...
1
vote
2answers
135 views

host can't ssh guest, but guest can

This is a follow-up question from: Make virtualbox get a different IP address than my laptop. I ended up with these /etc/hosts files on both my laptop running Ubuntu 14.04 (the host) and my virtualbox ...
1
vote
3answers
583 views

Enabling IP forwarding at kernel compile time

I am compiling a kernel for a router. I know a way to enable IP forwarding in an existing Linux system. At compile time, CONFIG_IP_FORWARD is said to do the same task. I am configuring version 3.12....
0
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2answers
3k views

How to generate random IP addresses

$ nmap -n -iR 0 -sL > RANDOM-IPS-TMP.txt $ grep -o "[0-9]*\.[0-9]*\.[0-9]*\.[0-9]*" RANDOM-IPS-TMP.txt | egrep -v "10.*|172.[16-32].*|192.168.*|[224-255].*" > RANDOM-IPS.txt egrep: Invalid ...
0
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1answer
166 views

Problems setting up Ubuntu Machine as a router

I have been at this for over 24 hours, here is what I have so far. -I have an Ubuntu Server running version 14.04.2.amd64, called SV-01 -SV-01 has two NICs. ETH1 is for the external network (goes to ...
0
votes
1answer
2k 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?
0
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1answer
237 views

Make virtualbox get a different IP address than my laptop

I am trying to setup a 2-node Hadoop cluster (following this guide), where the master is going to be my Ubuntu laptop and the slave a virtualbox running ubuntu. I also read about networking in ...