the IP protocol and IP addresses

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1answer
43 views

mechanism of IP alias

I am a Linux admin beginner and knew that Linux can do so called ip alias today for the first time. My question: How can one NIC have two IPs at the same time? IP addresses must be identified by MAC ...
3
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2answers
282 views

IPv4 link-local address in Linux

I remember that in Windows XP, when DHCP client did not receive an IPv4 address from DHCP server, the host assigned itself an IPv4 link-local address from 169.254.0.0/16. However, I have never seen ...
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2answers
89 views

Meaning of address netmask without route to subnet?

My understanding is that the netmask of the interface tells what subnet the interface belongs to. Meaning of this information is that the routing system knows that packets to this subnet should be ...
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2answers
85 views

my linux pc not pingable using hostname

From a remote machine I am able to ping my computer by its IP address, but not by its hostname. How can I make it accessible by its hostname as well?
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1answer
260 views

How to add static route in Virtual Guest to reach Host network?

I have a Linux mint virtual machine running with public IP as 203.x.x.x with bridge mode Ethernet adapter whereas my physical machine IP Address is 145.17.x.x subnet. To access my physical PC's ...
2
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1answer
387 views

IP address assigned when using 3G USB modem

If I use a 3G USB modem with a SIM card on my linux machine, do I get the IP address assigned by the carrier just as my phone when it uses the same SIM card, or do I get a different IP address (as it ...
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0answers
263 views

Can't find connected devices on wifi network

I've been having some issues with finding my devices on the network.. Ettercap & nmap and everything else I have tried does not find a host that is connected to my gateway? I have three devices; ...
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0answers
60 views

server1 ssh's to server2 but server2 sees server1 by it's private ip due to both servers being on the same firm/network

I ssh into server1 via it's public IP from server2. I then ask server1 what my IP is. i.e. server2's IP. It shows me server2's private IP. I want it to show me server2's public IP. If server2 was ...
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1answer
76 views

Networking fundamentals: what IP is assigned a NIC if there is no successful DHCP negotiation?

On Windows computers, when there is no DHCP server found on the network interface, it gets assigned some IP address like: 169.254.x.x So it is supposed you can find it on the network using tools ...
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0answers
109 views

conntrack -E - traffic counter reporting

I'm currently in the process of writing small solution which would continuously receive output from conntrack -E command and along with some other stats, it would count/monitor traffic. The only ...
0
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1answer
2k views

scp ssh: connect to host 10.0.0.109 port 22: No route to host lost connection

I use SCP command on Debian Linux to transfer a file to my colleague via LAN. But I encounter the problem: $ scp filename.file username@10.0.0.109:/tmp ssh: connect to host 10.0.0.109 port 22: No ...
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2answers
34 views

How to use routing to use the next available inetface

My system has 2 interfaces (eth0, eth1). I open a socket and bind it with an ip attached to eth0, now I want the OS to route the packets to another ip (which attached to eth1 but i'm not sure it's ...
0
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1answer
657 views

Arch-Linux after system-update no internet connection but connection lan

Yesterday I updated my Arch Linux after 2 Months with sudo pacman -Syu and after the reboot I don't get any connection with the Internet neither from Browser nor with Skype, etc. When I try to ping ...
2
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1answer
545 views

Local port is not accessible with public IP address

I have a linux server which has public IP and Private IP. So, when ever I login with public IP, the terminal directly shows private IP. example: $ ssh root@55.27.XX.XX root's password: root@10.1....
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1answer
27 views

installed application keeps open port

I installed an application (a text editor) and it keeps a connection alive. I blocked the IP with iptables, but the port stays open. netstat shows: tcp 0 0 127.0.0.1:<port> 0.0.0.0:* ...
2
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1answer
151 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 ...
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0answers
70 views

Can two USB RNDIS gadgets with the same IP connect to one computer's VNC servers?

I have two android gadgets set to USB tether mode, connecting to one computer. I'd like to have one gadget connect to VNC on port 5900 and the other on port 5902. When they're both connected, the ...
2
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1answer
113 views

what does none in “tun0@none” stand for?

In the output of ip a I just got the lines: 4: tun0@NONE: <POINTOPOINT,MULTICAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UNKNOWN group default qlen 100 What does the NONE in there ...
3
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2answers
939 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@...
0
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1answer
375 views

Routing tables with two network interfaces

When I try to access the internet with my raspberry pi via ethernet, it works, but when I do ifdown eth0 and try to ping any server outside my home network, it tells me connect: Network is ...
0
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1answer
180 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 ...
2
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3answers
71 views

Is there a command to deny an IP

Looking at the access log I found excessive access from an IP address. I then edit either .htaccess or .conf files to deny access from that IP. I wonder if there is a command or a oneliner that can do ...
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2answers
267 views

`ip addr` in one-line per interface

I would like to print specific information about network configuration for different interfaces over all the servers I manage: the interface name the interface ipv4 address the interface hardware ...
0
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1answer
33 views

What things should be kept in mind while assigning static IP addresses to Virtual Machines

I always face problems pinging the base machine whenever I assign statics IPs to VMs. I also don't understand what gateway IP should I give,to connect to the internet or just to be able ping the Base ...
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3answers
57 views

Can't identify IP addresses

I got several interesting :) e-mails from IP addresses where I can't identify country and owner (internet provider), it's by example 10.180.221.97 10.220.113.130 10.52.135.39 I tried several IP ...
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0answers
102 views

How to communicate with modem over Ethernet?

I have an old modem I was considering repurposing. The first step I thought to do was connect my computer with the modem and try to map the open ports. I found that, upon connecting the device, that ...
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2answers
2k views

How safe is it to change the Linux Ephemeral Port range

I see the following ephemeral port range on my Linux box. sysctl net.ipv4.ip_local_port_range net.ipv4.ip_local_port_range = 32768 61000 I want to extend the port range to start from around ...
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1answer
90 views

Forwarding traffic coming from SSH tunnel to VPN tunnel on a Linux device

I want to route network traffic that comes from one end of an ssh tunnel (constructed by ssh dynamic port-forwarding) into one end of a VPN tunnel. Given four Linux devices A, B, C and D, for ...
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2answers
1k views

Tell socat to listen to connections from a single IP address

socat TCP-LISTEN:22,fork TCP:192.168.0.15:5900 How can I tell to socat, that port 22 is only trusted from the remote IP address 8.8.8.8, and it should not accept connections from other IP addresses? ...
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1answer
58 views

Delay after a MAC change

I am writing a script that will change my ethernet MAC address on a local network. It will work as follows: Initially eth0 will be brought down MAC will be changed using the ifconfig utility eth0 ...
0
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1answer
42 views

Letting a device access the Internet through an Ethernet port via a laptop [duplicate]

I have Internet access to my laptop, over Wi-Fi. I have connected a device with an Ethernet port (with an Ethernet cable from my laptop to the device), and set up a local area network between the two, ...
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68 views

Script to remove IPs or network ranges from an IP space

As per the tittle, I have a tool that accepts both lists of IPs or network ranges (CIDR format) to perform a task. Unfortunately, it does not support exclusions of IPs or ranges from the IP space ...
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0answers
979 views

Hostname resolves to wrong IP address

When I ping the hostname of my phone from a RaspberryPi (with Raspbian installed), it resolves to the wrong IP address: pi@raspberrypi ~ $ ping isimon.fritz.box PING isimon.fritz.box (192.168.178.153)...
0
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1answer
196 views

Gentoo: how do I get an IP assigned to the network interface?

I'm noob. I'm trying to install Gentoo from the LiveCD (just for fun as well as for getting better understanding what's going on under the Linux's hood) on my notebook. I've faced an issue which is ...
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0answers
623 views

VirtualBox network interface with custom CIDR and internet access

I have an OpenStack setup running on VirtualBox. The host OS is Ubuntu, and the guest OSes are all Ubuntu. I use 3 VirtualBox VMs to setup and install OpenStack. My OpenStack setup further spawns ...
2
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0answers
143 views

Binding nonlocal address on NetBSD

This is not a programming question, but a question about NetBSD. Linux, FreeBSD and OpenBSD have mutually exclusive but similar interfaces to allow binding the local end of a connection to an address ...
3
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2answers
446 views

What is stopping our UDP packets (how does it know the route is down)?

We have a server (camera) sending RTSP video packets via UDP. At a customer site it travels over several hops, one of which may be an unreliable WiFi link that drops the odd packet or five. Usually ...
1
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1answer
123 views

What ports will an ssh daemon use outbound?

I am making a bastion ssh server. When I use the following rules in its ip tables, I am able to connect to the server just fine: Inbound Rules Allow traffic on port 22 from my client's IP Block all ...
1
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1answer
346 views

Static IP changes to dynamic automatically after time

I have found only one discussion about my problem here, but not a solution. I have access to one Debian 7.8.0 amd64 virtual machine (under VMware) and its IP address is gained through DHCP, e.g., 192....
2
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2answers
267 views

How can I allow SSH and SMTP only using IPTables?

I've got a raspberry pi set up to send me periodic emails. As it's connected to the internet 24/7, I need IPTables set up properly. I want to allow incoming SSH and allow emails to send out on port ...
1
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1answer
534 views

Why `ip addr` showing inet 192.168.122.1/24?

My local ip address is : 10.102.42.102, but i don't understand the rest of the address. Can someone explain why ? root@HitHiFitHai:~# ip addr 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc ...
2
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2answers
217 views

How can I change the IP and gateway addresses permanently?

I recently installed Linux Ubuntu 14.04 to my computer. To enable internet connection I needed to change my IP and Gateway address. I did the following as a root user # ifconfig eth0 "my ip address ...
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77 views

CentOS 6 Include Gateway for Static IP Address

I've just set up a static IP Address for my CentOS Machine using the following settings in /etc/sysconfig/network-scripts/ifcfg-eth0 #eth0 Config #IPv4 DEVICE="eth0" NM_CONTROLLED="yes" ONBOOT=...
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1answer
118 views

Interfaces, IPTables, Connections, Local Connection - Confused :/

I configured my iptables today and ran into some questions i could not resolve yet. So it would be nice, if someone could verify or answer the following to clarify: Each interface can be configured ...
2
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1answer
658 views

How can I share my internet connection (wireless) with an ethernet only computer?

I have a raspberry pi B+ set up in a server configuration and it connects to internet succesfully over Wifi with a USB dongle. My other pi (an A+) has always been located downstairs in the garage, ...
3
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1answer
134 views

package from IP arrives at certain port => open portrange to IP for x seconds

I have been toiling with an issue on iptables: I am trying to make a portrange open to a specific IP for x seconds/minutes as a result of a single packet being sent to a specific port. Not exactly ...
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1answer
4k views

How does OpenVPN server assign client IP addresses in case of multiclient configuration?

For a multiclient OpenVPN configuration, as we can find from the relevant documentation (server.conf comments), Configure server mode and supply a VPN subnet for OpenVPN to draw client ...
0
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1answer
359 views

noip2 can't update my IP address correctly after computer reboot

I want to set up a server with using no-ip DDNS service. I follow this guide, but it can't update my IP address after reboot the following message is command # noip2 -S 1 noip2 process active. ...
0
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1answer
709 views

How to make virtual interface ping to a host in the network

I crated a virtual interface as indicated in this link. sudo modprobe dummy sudo ip link set name eth10 dev dummy0 sudo ifconfig eth10 up sudo ifconfig eth10 192.168.1.150 now if I want to make a ...
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0answers
511 views

Add vlan to interface with unique mac - different syntax for different Linux distros

I need to add a subinterface to an existing interface, which is on a VLAN. Furthermore, the subinterface must have it's own MAC address. Through the man pages I found this syntax which works fine on ...