the IP protocol and IP addresses

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3
votes
1answer
484 views

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) ...
2
votes
1answer
454 views

Masquerade not working sometimes

I have an issue with private network traffic not being masqueraded in very specific circumstances. The network is a group of VMware guests using the 10.1.0.0/18 network. The problematic host is 10.1....
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 ...
1
vote
2answers
12k views

How to determine eth0 gateway address when it is not the default gateway?

In my system I have eth0 (which may or may not be connected) and a modem on ppp0 (which always may be up or down). The the case where both interfaces are up and ppp0 is the default route, I'd like to ...
1
vote
3answers
581 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....
1
vote
1answer
3k views

How to request a specific IP address from DHCP server?

I'm running Angstrom Linux on an embedded device (BeagleBoard-xM). I managed wireless connection via a Wi-Fi adapter. When I load its driver using modprobe, BB-xM requests an IP address from router ...
0
votes
4answers
205 views

Linux routing tables

I'm trying to learn Linux routing tables and ran into bit of snag. In the example below I'm not sure what is happening. My understanding is 0.0.0.0 means that for line 1 and 2 any packets outside of ...
2
votes
1answer
380 views

How do I create an IPv6 overlay network?

I would like to create host-only IPv6 networks on two hosts and then route between them. On each host, there will be a dummy interface, at ipv6_prefix::9. I would like to be able to ping that ...
4
votes
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 ...
9
votes
3answers
4k views

How does one capture traffic on virtual interfaces?

I would like to capture traffic on Linux virtual interfaces, for debugging purposes. I have been experimenting with veth, tun and dummy interface types; on all three, I am having trouble getting ...
1
vote
1answer
251 views

tcp/ip - trigger action or event after period of no network activity on certain port(s)

Is it possible, perhaps using iptables or one of the wrappers/frontends to iptables, to trigger an action or run a script after a certain period of time has elapsed with no network activity on a ...
4
votes
2answers
14k views

Can't access ssh in my VM Centos

My Cento's IP is diferent of the normal. And I cant access it in a ssh command And when I tried access using ssh noting I want to use ssh and samba client, but my IP is diferent. And I have ...
0
votes
1answer
589 views

installation causing error

I have downloaded g2ipmsg from http://www.ipmsg.org/archive/g2ipmsg-0.9.6.tar.gz while installation this package it causing some error checking for G2IPMSG... configure: error: Package ...
1
vote
2answers
481 views

What could cause a ping request to return inconsistently timed results

Here is a sample run: 64 bytes from 192.168.1.9: icmp_seq=27 ttl=64 time=8852.917 ms 64 bytes from 192.168.1.9: icmp_seq=28 ttl=64 time=7918.074 ms 64 bytes from 192.168.1.9: icmp_seq=29 ttl=64 time=...
2
votes
1answer
5k views

Virtualbox NAT + Host-Only Adapter

My host is Ubuntu 12.04 and guest is a Debian squeeze (LAMP server). I want to allow the host to connect the guest. and allow the guest to connect the internet. The guest should not be enabled from ...
3
votes
1answer
187 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 ...
0
votes
0answers
478 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.: ...
4
votes
5answers
14k views

How to get netmask from bash?

I want to get my netmask on Linux. It is outputted with ifconfig but I want to extract the string.
3
votes
1answer
989 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 ...
0
votes
1answer
53 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, ...
1
vote
0answers
122 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 ...
2
votes
1answer
943 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/...
0
votes
1answer
99 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 ...
0
votes
1answer
269 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 ...
1
vote
0answers
217 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 #...
0
votes
2answers
524 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 ...
0
votes
2answers
2k 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. http://192.168....
1
vote
1answer
4k 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?
6
votes
1answer
296 views

Looking for elegant iproute2 solution for host w/ 2 interfaces on 2 networks and 3 gateways

I've got a Linux webserver with 192.168.0.2/24 assigned to eth0 and 172.16.0.2/24 assigned to eth1. I must not change this. Here's the routing so far: 172.16.0.0/24 dev eth1 proto kernel scope link ...
0
votes
2answers
6k 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 ...
7
votes
2answers
7k views

How to build a gateway from my Linux OS

I want to configure my Linux so that it will be used as a network router (gateway). Can anybody give me some hints on this? (links are welcome!)
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....
0
votes
1answer
388 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 ...
1
vote
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 ...
1
vote
2answers
137 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 ...
1
vote
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 ...
1
vote
1answer
960 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 ...
8
votes
2answers
4k views

How can I disable TCP/IP for an Ethernet adapter?

I have CentOS 6.3 running in a (virtual) machine with two Ethernet adapters. I have eth0 connected to a TCP/IP LAN and eth1 connected to a DSL modem. The system is intended as a dedicated router/...
0
votes
1answer
71 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
693 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
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
2answers
848 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: <12&...
3
votes
4answers
22k views

SSH is suddenly not working anymore: “Write Failed:Broken Pipe”

I use a macbook pro at home and regularly ssh into the machines at my lab. For the past 3-4 days however, whenever I SSH into the machine in the lab, I get a Write Failed:Broken Pipe error, hardly ...
1
vote
2answers
943 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 ...
1
vote
3answers
444 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 1.2.3....
2
votes
1answer
2k views

explanation of the output's command “ifconfig ppp0”

I'm trying to understand the meaning the output of the command: ifconfig ppp0 Note that I'm using an internet-usb-board and so I'm sure that ppp0 interface is associated to it. In particular I have ...
1
vote
0answers
307 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 ...
2
votes
1answer
290 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
vote
0answers
277 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
vote
1answer
50 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 ...