Managing and using network connectivity on a unix system

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7
votes
3answers
26k views

CentOS on HyperV - eth0 not in ifconfig?

I've launched a CentOS install in HyperV and assigned a NIC the same way I've done on an Ubuntu VM, however, the device simply isn't picked up. Only my loopback is found by ifconfig. How should I go ...
1
vote
1answer
335 views

Multicast on local box

I have an application I need to interface with that listens to a multicast address. I'd like to be able to run a program I've written and have it interface with the other application by multicast ...
1
vote
2answers
2k views

Check the Existence of a Network Interface Card Redhat

I'm aware that I can use ethtool eth0|eth1|eth2 to check the existence of a NIC. But I wonder where the files are on the machine that contain information of an existing interface, as I need to use ...
5
votes
1answer
3k views

Changing Redhat Network Settings From DHCP to STATIC IP Via Configuration Files

In order to make the statically assigned IP work, I have already modified the file /etc/sysconfig/network-scripts/ifcfg-eth0 as follows: DEVICE=eth0 IPADDR=10.33.17.143 NETMASK=255.255.255.0 ...
2
votes
4answers
944 views

Is there a way to determine machine hostname without touching “/etc/hosts”?

Considering that I'm in a LAN that assigns IP addresses using DHCP (and that I'm not its administrator), how do I set things up such that when I ping <hostname> (instead of ping <IP ...
33
votes
3answers
57k views

How to make a machine accessible from the LAN using its hostname

Here are details of the machine I want to access using its hostname: $ hostname hostname $ cat /etc/hosts 127.0.0.1 localhost 127.0.1.1 hostname.company.local hostname It's a default Debian 6 ...
2
votes
2answers
1k views

iscsi target to a folder of a mounted parition?

i'm thinking about installing and setting up iscsitarget on my Debian squeeze box. so far, the examples i saw on various Google searches and the debian wiki: ...
7
votes
1answer
3k views

Why is VirtualBox Bridged networking slow

When logged into the guest, data transfer (scp) from the host is very slow (<1MB/s). Is this expected? setup: VirtualBox host is Debian Unstable VirtualBox guest is Debian 6 (Squeeze) Bridged ...
1
vote
1answer
681 views

Only allow ssh/vpn on OpenWRT

If I don't want to use wireless encryption, but I still want security and I want to use sshuttle (on the clients, see: https://github.com/apenwarr/sshuttle/) for tunneling everything through an SSH ...
5
votes
4answers
2k views

How to share the internet connection?

An ordinally network topology in picture: In words: - "server" (e.g.: an Ubuntu 10.04 LTS) is connected to the "internet" through pppoe connection - "server" is using it's wireless card in AP ...
1
vote
1answer
1k views

Redhat Network Service Restart

I modified the /etc/sysconfig/network-scripts/ifcfg-eth0 file to set a static ip for my redhat. Then I tried to use command "service network restart" to make the change stick, however, it became stuck ...
5
votes
4answers
3k views

ssh hanging then time out

I am new to ssh on linux. I have two computers connected on a switch. The first one is 192.168.1.2 and the second is 192.168.1.3. When I use the ping command I got a reply and everything is good, but ...
24
votes
1answer
11k views

Why are the first 1024 ports restricted to the root user only?

This is more idle curiosity than anything else. A friend of mine asked me 'which port range is it that only root can use under Linux?' I told him 0-1024 were restricted. Then he asked my why it was so ...
10
votes
2answers
10k views

How to refuse routes that are PUSHed by OpenVPN server?

When I establish an OpenVPN client connection over the Internet to our corporate OpenVPN server, it pushes several static routes. Unfortunately, these routes break some connectivity within my local ...
4
votes
1answer
1k 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
8k views

Firmware for wireless card on Ubuntu/Debian?

This is a follow up to my previous question about Debian support for Linksys Wusb600n. I have tried running the Ubunut/Xubuntu LiveCDs and the WiFi does not come up. The Gnome Network Manager menu ...
19
votes
5answers
4k views

What is a socket?

Could someone explain to me what a socket is? I see it in many acronyms in context of SSL, etc. Also, why is it called a socket? Is it purely because it was what a name they invented? Or was it the ...
0
votes
2answers
861 views

Linksys wusb600n support on Debian-6

I'm on my way from Windows 7 to Debian 6. The only problem... I'm not sure about my network adapter. Its Linksys wusb600n and without it - no internet access for me. Does Debian 6 support it? Will ...
9
votes
2answers
1k views

How do I hide/anonymise/defend a computer when on hostile networks?

I connect to a lot of open networks when I'm pootling around. I'm fairly careful to VPN home for anything important but that's not really my boggle. The laptop runs several services (nfs, dev http ...
2
votes
1answer
1k views

Bonding wireless and 3g on Fedora 15

I have access to the internet through either wireless or a 3G CDMA card. Is it possible to bond both connections and join the bandiwdth and have a failover?
5
votes
1answer
1k 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 ...
-2
votes
1answer
262 views

How Can I “CAM attack” a switch/router?

Does someone has any script that can "CAM attack" a switch/router, so that it will act as a HUB? Are there any tools for it in the repositories?
2
votes
5answers
800 views

Remotely access Linux box with no IP address

I have two *nix boxes that are connected via ethernet. However I only have physical access to one of them. In working on the "remote" computer I messed up the ifcfg-eth0 file and instead of typing ...
3
votes
2answers
2k views

Setup WLAN interface on Debian

I am trying to configure wlan on my dockstar. I installed wireless-tools, zd1211-firmware and wpasupplicant. My /etc/network/interfaces file looks like this: auto lo eth0 iface lo inet loopback ...
1
vote
1answer
971 views

How to access shared locations on a windows machine from a linux machine via terminal?

I’ve setup a Virtual CentOS machine and set up a bridged network and static IP so that it can communicate with other Windows machines in the network. Currently, to access any shared directory, I ...
2
votes
1answer
946 views

Tool to monitor in and out data network traffic w graphs and detailed stats

Is there a tool, that can gather stats on network usage? Requirements: Generate HTML (or other format, convertible to HTML) Time line graphs for bandwidth usage, also which hosts use the most ...
1
vote
1answer
657 views

Network fail on FreeBSD: Ping to router fails, but router believes computer is connected

I have a TP-Link TL-WN851N wireless adapter, which is based on an Atheros device. When I attempt to connect to my WPA2 wireless network, ifconfig wlan0 tells me that the connection is 'associated'. My ...
4
votes
2answers
1k views

Telnet over Ethernet for Linux?

I have used MikroTik RouterOS and I found a telnet-over-Ethernet (a layer 2 telnet), MAC telnet on it. I think it's a great tool, when SSH dies, or someone misconfigures IP Addresses. So the thing ...
4
votes
1answer
1k views

How can I configure fair bandwidth sharing between cgroups?

It's fairly easy to use tc with Stochastic Fairness Queueing (SFQ) to configure fair bandwidth sharing between flows, but an application can open multiple flows and get an unfair share of bandwidth. ...
2
votes
1answer
362 views

Сan I configure FreeBSD to use DHCP or a static IP depending on the detected ssid?

I have a FreeBSD 8 machine which can use several wireless access points. I want it to use the first available network and automatically use DHCP or a static address as required (this should be ...
0
votes
2answers
954 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 ...
1
vote
3answers
16k views

Installed TigerVNC, can't connect?

I've just installed TigerVNC on my Fedora 15 machine from the package manager then in terminal (as root): chkconfig vncserver on service vncserver start None gave me errors, so I went back to the ...
2
votes
1answer
2k views

Unable to make outbound SNMP connections when IPTables is enabled

I have a bunch of windows servers configured with the windows SNMP agent. Each server has four IP addresses and SNMP listens on all of them. There is something very odd with my monitoring server ...
3
votes
1answer
274 views

Set up network to share a printer connected to one particular machine on the network

How do I set up my Ubuntu machine to allow other computers to print to it? The set up is: All computers are connected to the network 1 dual Ubuntu/Windows 7 netbook 1 multibooting ...
2
votes
1answer
623 views

How to execute udhcpc as non-root

On a Linux machine, I am trying to run the udhcpc command as non-root. I am getting the error udhcpc: socket: Operation not permitted. Is there any way to execute udhcpc as a simple user in Linux?
6
votes
2answers
912 views

Configuring a vncserver so it's only accessible from my ssh tunnel

Since I use vnc through an ssh tunnel, is there any way I can block the open vnc port that the remote machine is listening on without it affecting my ability to use the ssh tunnel? Both machines are ...
2
votes
2answers
1k views

Reducing packet loss in tc rate limiting

I use this tc command to limit upload speed on an interface: tc qdisc add dev eth1 root tbf rate 2mbit burst 10kb latency 70ms peakrate 2.4mbit minburst 1540 But it results in heavy packet loss. ...
7
votes
2answers
1k views

Suggestions needed for udev, udisks, autofs, notification setup for a complete automounting solution on Linux

Continuing on Automounting plugged devices in linux, which left things a bit basic. Running Gentoo, I'm automounting a combination of local and network devices on my laptop with autofs-5.0.4-r5. Doing ...
2
votes
1answer
411 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
720 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 ...
1
vote
1answer
640 views

Fedora 15 won't remember wireless password

I just installed Fedora 15 beta with Gnome 3. I've done all the updates. The networking applet asks for the wireless password every time it connects. I found this bug, which says that the issue is ...
1
vote
2answers
665 views

Socksify like program for Fedora?

I need a program that allows me to pass an application through a socks server, even if the program does not have native socks support. Under Ubuntu I can use socksify for this. What can I use under ...
19
votes
2answers
15k views

how to check rx ring, max_backlog, and max_syn_backlog size

Quite often in the course of troubleshooting and tuning things I find myself thinking about the following Linux kernel settings: net.core.netdev_max_backlog net.ipv4.tcp_max_syn_backlog ...
2
votes
1answer
514 views

ntop versus mrtg

I'm evaluating tools for measuring network activity and although mrtg seems to be the most highly regarded, I'm really impressed by ntop. Are there any reasons that mrtg is preferred to ntop?
1
vote
3answers
8k views

How to reach a Vbox guest from host when using NAT networking

Using Fedora or Ubuntu for the host with firewalls turned off on each side (vbox guest&host), what do I have to do to reach the guest machine using a NAT interface just like it would be with a ...
3
votes
2answers
600 views

How to block outgoing connections from process/user on FreeBSD?

My server executes third party software which processes user submitted files. I want to block outgoing connections from my process. How can I do it in FreeBSD?
2
votes
1answer
929 views

netcfg error in Arch: 'Profile doesn't exist'

To setup automatic wireless connection in Arch, I configured netcfg as directed in the Arch wiki. When I try: [root@geckko ~]# netcfg adsl it gives an error: > Profile "adsl" does not exist ...
6
votes
1answer
308 views

`hostname` - host name or FQDN?

What is the right thing to set a computer's hostname to? (/bin/hostname, /etc/hostname, sethostname(2), etc.) I usually just use the "name" part, and it works perfectly (for me at least), but I've ...
10
votes
3answers
12k views

Only allow certain outbound traffic on certain interfaces

I have rather an odd issue. I have a server with two network interfaces eth0 and eth1. Each are connected to a different network. Each network has a internet gateway. The server has various outbound ...
2
votes
1answer
432 views

Whole program name not visible in nethogs

I'm using the command sudo nethogs to watch network traffic. I have a problem in that the name of the program is too long (it doesn't fit in the PROGRAM column). I haven't found any nethogs ...