the IP protocol and IP addresses

learn more… | top users | synonyms

11
votes
3answers
13k views

How can I block a range of IP addresses with an Amazon EC2 instance?

I know a certain range of IP addresses are causing problem with my server, 172.64.*.* what is the best way to block access to my Amazon EC2 instance? Is there a way to do this using security groups or ...
1
vote
0answers
547 views

AIX multihomed multicast

On my AIX machine if I run netstat -ia I get: Name Mtu Network Address Ipkts Ierrs Opkts Oerrs Coll en0 1500 link#2 1e.18.1.1e.78.2 385229 0 1091655 0 0 ...
2
votes
0answers
146 views

How to fairly share bandwidth between IPs with tc?

I have a linux router (d-link 320-nru) with tc installed. I have some users' computers to fairly share bandwidth between them. Also there is such complication as inconstant uplink bandwidth. How can ...
2
votes
1answer
113 views

Gentoo on VM setting IP Manually

I installed Gentoo on Virtualbox with the minimal image. This is the first time I am running gentoo. I need to do ifconfig eth0 192.168.0.10 route add default gw 192.168.0.1 everytime it boots on ...
4
votes
6answers
855 views

Find my computer on a LAN network

Let's say that I have a computer plugged in to a local network using a dhcp connection, so it will get a different IP every time. Is there a way to find this computer (so the IP) from a different ...
9
votes
3answers
20k views

Why are my two virtual machines getting the same IP address?

I have two virtual machines both running on a Linux host (Fedora 16). I set both adapters as attached to NAT. When I boot them up they both have their default gateway set to 10.0.2.2. They also ...
2
votes
1answer
11k views

tcpdump: “packets captured” vs “packets received by filter”

We have a script which calls tcpdump -v src host <IP address> and port <port number> >>out.txt 2>>err.txt -w capture.cap on multiple IP-s while the other parts of the script ...
3
votes
3answers
16k views

How can I get the address of my local machine?

I'm on a macbook running Lion. In Terminal I'm connected to my schools server with ssh. I navigated to a folder on the server and have a file I want to copy to my local machine, but I don't know what ...
6
votes
2answers
5k 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!)
2
votes
1answer
6k views

Static route in Centos 6

Here is my route -n output: Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface 192.168.122.0 0.0.0.0 255.255.255.0 U 0 0 ...
4
votes
1answer
274 views

Inserting a nat solution into a network while it's not the gateway

I have tried this a few different ways. Currently trying with pf on freebsd 8.2 I am trying to insert a nat solution into an existing network that will redirect traffic from an outside ip address to ...
2
votes
1answer
449 views

Should OpenVPN point to point tunnels be on different ports?

The OpenVPN cookbook shows an example for site-to-site VPN (3 sites). They configured each tunnel on a unique port: site A to site B: 1194 site A to site C: 1195 site B to site C: 1196 The author ...
3
votes
2answers
1k views

IP rule for IPv6

When I try to add an IP rule for IPv6 on my Linux system, it errors out: $ ip -6 rule add fwmark 0xfab lookup 0xf RTNETLINK answers: Address family not supported by protocol I checked out the IP ...
2
votes
5answers
4k views

script to scan ip range and return results in a certain format

This script scans IP's and returns a status of Up or Down. How can I alter it so it doesn't scan everything twice? As it sits it scans everything and returns the "Up" addresses only and then scans all ...
2
votes
1answer
3k views

Testing if a port was forwarded correctly in Ubuntu

I have a Ubuntu box connected to a wifi router. This wifi router is connected to a d-link adsl modem/router. I am preparing this Ubuntu box to run a server that will use some special ports in UDP and ...
48
votes
2answers
6k 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 ...
2
votes
1answer
513 views

ICMP destination unreachable

I am working on an Arch Linux machine with an ethernet interface eth1. I have created the interface eth1:0 using ifconfig and given it a dummy hardware address (00:01:02:03:04:05). When I send a UDP ...
7
votes
3answers
7k views

What's the last number in this ip address?

An IP address like this 223.248.0.0/24 or 223.248.0.0/16 What's the last number mean in the IP address (24 or 16 in the above example)? Is there a simple way to understand how to set the number ...
4
votes
2answers
414 views

How can I use one network port for VPN and the other for everything else?

My Linux machine has two network ports with two IP addresses. I want to use one port for my VPN and accounting, and the other port for other usages. How can I tell Linux not to allow any requests from ...
3
votes
1answer
467 views

What is the kernel doing when I bring a TUN/TAP interface up

I'm playing around with the TUN/TAP device on Linux. I've created a simple program that creates a TAP interface and prints anything that is sent through it. When I bring the interface up with ip link ...
7
votes
3answers
46k views

How can I know if IP Multicast is enabled

I have scripts that run IP multicast tests; however, my scripts are failing on a particular linux machine. I know that I can look at CONFIG_IP_MULTICAST in the kernel configuration file to determine ...
3
votes
1answer
438 views

Labeling/Aliasing multiple network addresses

If my machine is connected to several networks and configured with multiple addresses (ipv4), is it wise to configure and use labels to identify them ? By labels I mean the iproute2 ip command's ...
2
votes
1answer
3k views

iptrace for linux: how can I trace full packet contents?

I normally use iptrace on our AIX servers to get packet traces but have recently found out that this doesn't work for other 'nix systems - namely Centos. Does anyone know what the analog would be? ...
1
vote
2answers
370 views

Is it possible assigning an separate LAN IP to service/daemon?

I'm using pfsense for prioritizing traffic around LAN. It works well for specified port, IP, network, but I'm having a problem with torrent (transmission bittorrent) outbound connections. The outbound ...
3
votes
1answer
229 views

Detecting multihomed machine

Is there a way to reliably detect whether or not a machine is multi-homed? I'd like to be able to write a script that will return a true or false regarding that information.
2
votes
5answers
8k 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.
4
votes
2answers
869 views

How to configure Linux to use DHCP or static IP depending on presence/absence of DHCP server?

I would like to configure a network interface to make use of DHCP if a DHCP server is present on the network during boot, but otherwise default to some default static IP address.
2
votes
2answers
304 views

How to deny rdesktop access to others?

Someone keeps trying to connect to my Ubuntu machine through remote desktop. Is there any way I can determine who it is, and permanently block access to my machine?
10
votes
2answers
21k views

show gateway IP address when performing ifconfig command

Currently, when using the ifconfig command, the following IP addresses are shown: own IP, broadcast and mask. Is there a way to show the related gateway IP address as well (on the same screen with ...
76
votes
19answers
64k views

How can I get my external IP address in bash?

I need to find my external IP address from a bash script. At the moment I use this function: myip () { lwp-request -o text checkip.dyndns.org | awk '{ print $NF }' } But it depends on ...
4
votes
4answers
7k views

Make some virtual MAC address

I want to make some virtual MAC addresses for my network adapter or wireless adapter, so I can connect to network with more than one IP address from one computer or laptop. How can I do it? (I know ...
-1
votes
1answer
513 views

How to “grep -v” private/broadcast IPv4 addresses?

time nmap -n -iR 0 -sL | cut -d " " -f 5 | egrep -v "^10.*|^172.[16\-32].*|^192.168.*|^[224\-255].*" > RANDOM-IPS.txt so the important part is: egrep -v ...
2
votes
1answer
791 views

static ip to a freebsd server

I have Comcast cable <====> modem <===> router <===> freebsd server My freebsd server is connected to wireless router via a network cable. What I want to do is, to have a static ...
5
votes
3answers
4k 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
686 views

Is it possible to use Internet Connection Sharing with DHCP?

I know it is possible to share an internet connection with another pc using ip-forwarding and masquerade. Is it possible to set up the sharing computer as a DHCP server, so the settings (ip, gateway, ...
4
votes
1answer
2k views

How to set a static IP in Ubuntu

How do I set my computer to have a static IP in Ubuntu 11.04? The only two lines in /etc/network/interfaces are: auto lo iface lo inet loopback I think usually when people do this they have a wired ...
4
votes
2answers
2k views

What tools do I need to intercept and change an incoming packet on a WP2-Personal wifi hub

Which tools should I research into to intercept a plain text packet, edit it and then continue it on it's way. I am using Ubuntu 11.04 and Backtrack 5; my wifi is WPA2-person encrypted. I need to edit ...
5
votes
1answer
2k views

Two IP addresses assigned to the same machine?

I seem to be using two IP addresses on my PC. I use DHCP to get an IP address and then I statically set an IP address and activate it. ifconfig says that I am using the address given by DHCP but I am ...
0
votes
2answers
2k 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 ...
4
votes
1answer
1k views

Running vim on a remote Linux machine “freezes” OS X SSH connection

(cross-posted this from SuperUser as the question seems more relevant to this audience) I am attempting to SSH to a Linux (Fedora 14) machine and then open up vim to edit a file, however on my new ...
0
votes
2answers
951 views

Understanding tcpdump output on a linux router

My router has an atm0 interface and a VLAN (atm0.1) interface, atm0.1 has the WAN IP address. When using tcpdump -i atm0, the packets captured are only outgoing packet (LAN to WAN). 05:34:19.504895 ...
12
votes
1answer
15k 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 ...
2
votes
1answer
410 views

Can't access HTTP contents, but HTTPS and SSH are fine

I'm having a weired issue wih my Fedora 14 recently. Many details involed. Let's start from this: I've been using Fedora 14 for months, and recent few days, offten I can't access Internet for hours. ...
1
vote
3answers
718 views

How to set Internet Protocol properties using terminal?

When I set up a Virtual Machine with windows (using VMPlayer), I set the Network Connection properties from the VM settings from NAT to bridged. Then I proceed to set the following IP Properties in ...
2
votes
3answers
449 views

Port monitoring on GNU/Linux based NAT router

I am using a Ubuntu machine as a NAT router. How can I find out the following: the ports on which the LAN machines are listening or communicating (both tcp and udp); which local machines have ...
3
votes
3answers
2k views

Accessing a linux machine with a name (not ip address)

When I access a linux machine with sshfs, I take the following steps. Get the ip address of the linux (the ip address is dynamically allocated to linux) Run sshfs id@ip_address:/HOME_DIRECTORY Can ...
1
vote
3answers
1k views

Connect my laptop through desktop to internet

I'm currently at work and our wifi is down. I usually connect my desktop to the internet through eth0 and my laptop connects through wifi. I have an extra port on the back of the desktop (eth1) and ...
4
votes
3answers
3k 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 ...
3
votes
4answers
2k views

Sniffing packets through router

I would like to create a system like this. The user would connect through a wifi network which would reroute all http requests and responses through the network card on a computer thus allowing that ...
19
votes
7answers
19k 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?