The ip tag has no wiki summary.
7
votes
3answers
2k 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
245 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
233 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 ...
1
vote
3answers
7k 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
116 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
710 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
220 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
187 views
Detecting multihomed machine
Is there a way to reliably detect whether or not a machine is multihomed? I'd like to be able to write a script that will return a true or false regarding that information. Thanks.
2
votes
4answers
1k 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
416 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
134 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?
2
votes
2answers
1k 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 ...
1
vote
2answers
1k 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
255 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
274 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 ...
4
votes
3answers
2k 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
347 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, ...
3
votes
1answer
538 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
780 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 ...
3
votes
1answer
486 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 ...
-1
votes
2answers
668 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 ...
1
vote
1answer
397 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
546 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 ...
2
votes
2answers
1k 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 ...
1
vote
0answers
276 views
Wrong route taken on a network with two gateways [closed]
In the following output, why does vpn1 route pings to 10.100.0.1 instead of 10.100.0.112? 10.100.0.1 is a network gateway with no NAT; 10.100.0.112 is a dual-homed host with NAT enabled.
root@vpn1:~# ...
2
votes
1answer
287 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
564 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
265 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
658 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
553 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 ...
2
votes
3answers
2k 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
1k 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 ...
11
votes
5answers
3k 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?
1
vote
2answers
457 views
squid (reverse proxy) configuration
I would like to configure squid in such way, so that only specific (public) ip (reverse proxy), could connect to the server, but I don't know how... can someone tell me how to do this?
6
votes
3answers
312 views
SpamAssassin Under Linux VPS
I am getting bald with this guys:
On a Linux VPS (CentOS), I have setup a mail server (Exim+Dovecot+Clamav+SpamAssassin) but scanning mail for spam using SpamAssassin is proving to be a challenge.
I ...
4
votes
2answers
1k 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 ...
3
votes
1answer
1k views
avoid IPv6 link local address on interface
I have a setup with virtual Xen hosts connected to a set of VLAN-s. On Dom0, I have set up a bridge for each of my VLAN-s to connect DomU-s to. Bridges are set up in /etc/network/interfaces like ...
5
votes
1answer
850 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.?
6
votes
2answers
720 views
Measuring internet connection quality
I'm having WLAN trouble on my dualbooting win/linux laptop - the connection on linux side has occasional trouble, and seems somewhat slow and chunky. I would try to fix this issue by fiddling with all ...
2
votes
1answer
286 views
Redhat Enterprise Linux 4.7 - Ping problem
When I try to ping some of the IP addresses I get "connect: No buffer space is available" error. Also when I check /var/log/messages, there are some errors like as following
printk: 99 messages ...
5
votes
3answers
2k views
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 ...
4
votes
1answer
845 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 ...
9
votes
3answers
783 views
Parsing log files for frequent IP's
So, I hacked this together while undergoing a DDOS attack to pull naughty ips out of my logs. Anyone have any improvements or other suggestions to make it better?
Here's the general idea:
pull ...
4
votes
5answers
6k views
How to route specific adresses through a tunnel?
There are certain websites/services which I can only access from the subnet on which my server is located (think of the typical intranet scenario). Is there a way to transparently route traffic that ...
