Managing and using network connectivity on a unix system

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15
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1answer
1k views

“ss” command in iproute package; why query slab table for timewait sockets?

Forgive me if this isn't the best forum for this question, but it seems more relevant to the kernel than to the programming itself. I'm writing a script that queries the system for open ports so that ...
0
votes
0answers
168 views

Network Interfaces Don't Exist After Loading Modules

I installed SourceMage Linux on my laptop and the ethernet and wireless interfaces don't exist after loading the required modules (tg3 and ath9k). On other distros (Xubuntu, aptosid) the networking ...
12
votes
4answers
3k views

Why do we need a firewall if no programs are running on your ports?

When I try to telnet to a port on a server, and if there is no program listening on that port telnet dies with a "Unable to connect ... " error. I understand that. But, why do we need a firewall if ...
2
votes
2answers
2k views

Per Socket network Buffer queues utilization

Is there a way to get a per-socket send and receive Queues utilization on Solaris similar to the way that Linux' netstat displays it? Example on Linux: Proto Recv-Q Send-Q Local Address ...
6
votes
3answers
35k views

how to ping & use specific network card

i have 3 network cards , 1 Lan (wired) , 1 wireless network card & 1 is wireless usb how do i ping from specific network card ? & how do i use specific network card for specific ...
4
votes
6answers
992 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 ...
5
votes
1answer
964 views

What is in the output of “getent ahosts”?

What are the fields printed by getent ahosts DOMAIN? The output for getent hosts is a simple combination of IP and hostname. The getent ahosts has an additional third field that is, in all my test, ...
1
vote
2answers
241 views

How can I use the same IP from the Internet and intranet?

I have an Ubuntu firewall box (Alma), at the office, with a web server on it. It looks like this: [Internet] <-> [DSL Router] <-> [Alma] | ...
4
votes
2answers
8k views

How do I resolve samba share to IP address or host name

I have a list of hosts in the network providing shares via SAMBA. How can I determine either IP address or the host name of one particular host, e.g. the one with the name “SASAK02”. The output of ...
-1
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1answer
2k views

How to transfer files over bluetooth?

How can I connect my mobile phone and Lubuntu 11.10 laptop over bluetooth so that I can transfer files between them?
2
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0answers
301 views

virtual network interface for ShrewSoft VPN Client

I use ShrewSoft VPN Client 2.1.7 under Arch Linux (i686) to connect to the company network using IPSec. It is configured by a .vpn file. How can I make it create a virtual network interface?
3
votes
2answers
828 views

Need help with routing

I have set up a Ubuntu server, that I want to use as a router for my local office. The problem is, that I want to make 2 VPN connections, to remote branches, and then I want to route all traffic to ...
9
votes
2answers
6k views

Merging two internet connections from two network interfaces in order to obtain double speed

I have two network interfaces (one wired & one wireless). I have two internet accounts too (each 256 kBps; one from a modem that I use as wired connection & the other from a wireless network). ...
2
votes
2answers
237 views

How to prevent user applications from knowing about network failure?

I have a very unreliable connection which disconnects quite frequently and becomes a massive problem when downloading, as the option to resume is not always available. The solution that comes to my ...
2
votes
1answer
1k views

Ubuntu machine with RNDIS tethered phone can not receive packets from internet

I tried to tether my old Windows Mobile 6 phone with my Ubuntu computer to use the phone's network. However, even though the kernel seems to recognize the phone and it is used as a network device I ...
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!)
2
votes
1answer
7k 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 ...
47
votes
8answers
84k views

What DNS servers am I using?

How can I check which DNS server am I using (in Linux)? I am using network manager and a wired connection to my university's LAN. (I am trying to find out why my domain doesn't get resolved)
9
votes
2answers
10k views

changing the names of network interfaces, debian wheezy

I'm trying to set a name for an interface, "ethLan" instead of eth0. Doing so also ensures that the if's name will remain consistent at every reboot and kernel. I did find some articles in the ...
4
votes
1answer
294 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 ...
1
vote
4answers
23k views

WiFI access in BackTrack 5 R1

I recently started using a live USB version of BackTrack 5 R1 (A kubuntu-based distro), but I can't find any way to enable access to my home WiFi network. I can't find any comprehensive tutorials on ...
2
votes
5answers
6k 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 ...
4
votes
3answers
6k views

Auto connect to a wireless network (Ångström Linux)

I am using Ångström Linux on BeagleBoard-xM. I have installed a RTL8188SU USB Wi-Fi adapter and configured it properly. But it doesn't connect automatically even though I have marked the interface as ...
30
votes
6answers
57k views

How to limit network bandwidth?

Problem: We are hosting an application on remote server. We need to test it with a limited network bandwidth (for users with bad Internet access). Question: Can I limit my internet bandwidth? For ...
2
votes
1answer
4k 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 ...
-1
votes
1answer
169 views

Linux 3.x: what wireless chipsets will support a bridged connection?

I have asked a similar question on the Ubuntu pages but this is likely a generic Linux issue: what variety of wireless cards/drivers will support being placed in a bridged connection? I have been ...
53
votes
2answers
7k 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
628 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
2answers
20k views

Check whether network cable is plugged in without bringing interface up

I am trying to identify NICs on ~20 remote servers (2-6 NICs on every server). To begin with, I want to identify those ready for use and free ones. How can I check the state of the physical media? I ...
5
votes
2answers
1k views

how to set what route would be added when bringing interface up

I have one two interfaces on one machine, one is the Internet connection that get its IP from a DHCP, no problem. The other interface (eth1) is to local machines, and it has the gateway 192.168.3.1 ...
3
votes
1answer
447 views

Configure applications to ask for a user:pass behind a proxy

Here's the deal: I'm trying to set up a SQL server with Debian Linux, I managed to install Debian - but I can't get apt-get to work, since I'm behind a proxy. I already managed to setup Iceweasel to ...
3
votes
1answer
824 views

How can I network these two computers using eth1394/firewire-net, automagically?

I have two partly-dead laptops. The first will not run X, and the second has some sort of problem with the monitor. I am not interested in repairing either of them, but since they both have firewire ...
2
votes
5answers
3k views

full access to remote computer without remote static IP

How can I access to remote computer that the remote computer is in a local network? I worked with reverse ssh : http://www.vdomck.org/2005/11/reversing-ssh-connection.html I don't want just SSH but I ...
7
votes
3answers
9k 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 ...
2
votes
3answers
8k views

Can ping any hosts but localhost. What's wrong?

I got a freshly installed red hat box on a server. I can ping another machine on the network usnig both ip and server name but I can't ping localhost or 127.0.0.1 or 192.168.4.42 (local ip) ...
3
votes
3answers
552 views

Questions about nmap

I have several questions about nmap. First, nmap can detect servers via: link-layer network-layer transport-layer What are the differences (not in the layer, but in the way that nmap does it) and ...
3
votes
1answer
695 views

Filter out HTTP GET request within wireshark?

I'm trying to filter out HTTP GET with wireshark, but the string provided on the official page isn't working at all: port 80 and tcp[((tcp[12:1] & 0xf0) >> 2):4] = 0x47455420 Wireshark on ...
4
votes
2answers
478 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 ...
0
votes
1answer
3k views

How to run tcptraceroute utility on UNIX machine?

How can I run the tcptraceroute utility on a UNIX machine? I want to run a TCP traceroute for port 80.
1
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0answers
381 views

Juniper SRX210, how to make DHCP to Static IP?

I am very new to Juniper device. I have a SRX210 router, and i am testing how to setup Static IP. So i did: set interfaces ge-0/0/0 unit 0 description ISP Link set interfaces ge-0/0/0 unit 0 family ...
22
votes
5answers
9k views

What is the need for rsync server in daemon mode

I don't understand the need for an rsync server in daemon mode. What are the benefits from it if I can use rsync with SSH or telnet?
5
votes
2answers
4k views

How to connect two computers via internet with ssh?

I want to connect another computer via internet that doesn't have a public IP. Is there any away to do this?
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0answers
203 views

configuration for my wireless connection

I had connection issues so I changed some wireless configuration. I think I solved the problem, but I still have minor issues. First thing I had my Internet connection freeze badly, Then after doing ...
2
votes
4answers
5k views

Can't Install/Update packages on newly installed CentOS

I installed CentOS6 and it is the first time. I tried to install/update packages. But I coudn't. Here is the output and it doesn't stop. How can I solve this? [root@localhost suranga]# yum update ...
9
votes
3answers
68k 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
0answers
749 views

tunneling FON traffic via Tor

I would like to tunnel the traffic of my FON router through Tor. For that I added a second network card to a local server and connected the FON router to it. Then I set up a DHCP server and configured ...
1
vote
1answer
461 views

NetworkManager on Fedora 15 can't find frequently used wireless network

NetworkManager has refused to find the wireless network I always connect to. It sees other wireless networks except the one which I need. In recent past occasions, I've had to delete the wireless ...
0
votes
4answers
4k views

How to set domain name in Crunchbang GNU/Linux?

How can I set the domain name in GNU/Linux?, I am using Crunchbang and I need to set the domain name for my LAN network. EDIT: Let me talk more about my problem: I need to configure a LAN network for ...
3
votes
1answer
669 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
4k 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? ...