Managing and using network connectivity on a unix system

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Enabling multicast communication between 2 AIX JVM processes

I'm having trouble with multicast distribution on a single AIX machine between two JVM processes. Think ehcache or jgroups. In order to enable on Mac OS X: route add -net 224.0.0.0 -interface lo0 ...
7
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1answer
7k views

Why are incoming packets on a TAP interface seen with tcpdump but not with iptables?

A program injects packets on a Linux TAP interface (these packets are coming from a virtual machine). Specifically, these are DHCP requests (so they're UDP). I can see the packets with tcpdump but not ...
3
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1answer
225 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.
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2answers
825 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.
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2answers
10k views

Oracle Linux 6.1 guest on Virtualbox 4.1 can't connect to network

I just installed VirtualBox 4.1 on my Windows system, and then added a Solaris 11 Express guest and an Oracle Linux 6.1 guest. Both installs went smoothly. But while the Solaris 11 guest has network ...
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1answer
454 views

How to configure a Frame Relay in Unix/Linux?

I am in a Networking course, the course employs a Cisco packet tracer to practice before the real implementation, but I only use GNU/Linux (Debian Squeeze) and I need to configure a next network ...
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1answer
662 views

How to enable TCP connection in Debian Squeeze?

I need enable TCP connections to my system, for use graphical applications in marionnet, network simulation system, in debian squeeze. In older versions of debian it is achieved with ...
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3answers
2k views

Arch Linux doesn't connect to a wireless network

I'm using Arch Linux on a Thinkpad machine. Everything was satisfactory but today I restarted my router and the machine doesn't connect. The router is fine (another machine and a cell phone connect to ...
2
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1answer
69 views

How do I proceed further when my reports of a improper functioning of a gnome component has not met with answers on the respective mailing list

I am unable to connect to internet using my modem. I followed instructions to seek help at http://live.gnome.org/NetworkManager/Debugging and posted on ...
3
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1answer
468 views

KVM: network partially lost for the host, guests are fine

I got KVM working fine on a Linux system, for quite some weeks. Then today something weird happened: suddenly the host (and the host only) lost some of its Internet access: it can still access the ...
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3answers
10k views

Wireless networking with CentOS

I'm running CentOS 5.7 x86 on my Vostro 1700 laptop which has an Intel Pro Wireless WiFi NIC (Intel Pro Wireless 3945 [iwl3945]). I'm a bit confused about how my Wireless connection (wlan0) is being ...
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1answer
2k views

what level of the network stack does tcpdump get its info from?

As I was trying in vain to fix a faulty ethernet controller here, one thing I tried was running tcpdump on the machine. I found it interesting that tcpdump was able to detect that some of the ICMP ...
2
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1answer
138 views

Start and stop multiple executable for easy debugging

I'm debugging a networking project, which involves interacting of 3 programs, ie a server, two different clients. However I find it difficult to start and stop them for debugging. Some methods I have ...
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1answer
8k views

Mount a Windows network drive

I want to mount a netword drive on the server (SBS2008). I have two options: Either using a fedora which already mounts on a CentOS server or directly on the CentOS server. Here is the command I tried ...
2
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1answer
2k views

Where are Proxy Settings Stored?

I'm coding a small application that connects to the Internet and retrieves information from my server using bsd socket. I looked at where the proxy settings are stored under Linux but i couldn't the ...
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2answers
3k views

OpenVPN bridge. Can't access machines on local network

Followed this guide: https://wiki.archlinux.org/index.php/OpenVPN_Bridge This is my setup: I have a wireless router(192.168.2.1) which connects to the Internet through a PPPoE connection and acts as ...
4
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1answer
2k views

Debian 6.0 system with 2.6.39 kernel dropping packets, sandy bridge hardware

I recently migrated an existing Debian system to new hardware, a core i3 chip running on an intel sandy bridge motherboard. I’m experiencing a very strange problem; when I ping my router, about 50% of ...
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1answer
608 views

rpc.statd and avahi-daemon listening on all networks?

Background: - I'm running a home Debian GNOME desktop connected to the internet through an ethernet cable to an ethernet router. - I have a printer connected directly to my PC with a USB cable. - My ...
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1answer
2k views

How to set IP adress automatically in Arch Linux?

I am using latest Arch Linux. But whenever I start my PC, it sometimes gets an IP address but most of the time, it gives me stress. I am getting very confused, how can I make sure it is really setting ...
4
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1answer
412 views

Throughput test setup with two local Ethernet interfaces

I'm currently testing the routing performance of a hardware device (DUT - Device Under Test) with the following setup (all addresses start with 192.168.): eth0 (29.2) <---> eth1 (29.1) eth2 ...
4
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2answers
13k views

Two interfaces, two addresses, two gateways?

I have a system that has two network interfaces with different IP adresses, both of which are in the public address range (albeit via NAT in the case of the first one) and both of which have different ...
3
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2answers
348 views

PCI configuration registers problem

I'm trying to get my new Realtek RTL-8169 NIC (over CardBus) to work, but I'm having this weird problem. My lspci -x output looks like this: [root@comp]# lspci -x -d *:8169 07:00.0 Non-VGA ...
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1answer
282 views

route traffic to github through specific network interface [closed]

okey, I'm a complete NAP, so take it easy on me :) My Situation; My computer is in this stupid cooperate network of the company i work for. They have alot of policies and stuff, so its not possible ...
2
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1answer
946 views

How to use tshark to do this task

I don't have any base knowledge about tshark, and it is hard to find any tutorial to help me with this. So now I have a pcap file which consists a lot of network flows; a time range; an ip addr; a ...
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2answers
2k views

minimal TCP MSS in Linux

The TCP MSS in Linux must be at least 88 (include/net/tcp.h): /* Minimal accepted MSS. It is (60+60+8) - (20+20). */ #define TCP_MIN_MSS 88U My question is: where did they come up with ...
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1answer
6k views

Where are NetworkManager's WiFi settings stored?

I remember the days of playing with /etc/$WE/wpa_supplicant.conf to try and force a semi-secure network on a debian based system, but now on to xubuntu, I haven't needed to do any *.conf-ing in a ...
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1answer
5k views

Linux Mint 11 won't connect to Windows 7 Wireless Ad Hoc

I apologise if this question has been asked before, but I am not exactly sure what I should be looking for, hence my reason for posting a new question. I am a newbie to Linux and have been using ...
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1answer
1k views

How to create an ad-hoc connection?

I need to make an adhoc connection on Archlinux (netbook used as a wifi repeater), I was using this tutorial to do it on Ubuntu : At the terminal install execute sudo apt-get install dnsmasq-base ...
2
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1answer
113 views

ifconfig shows an IP out of the lan range

I have set router IP to 192.168.112.20 and starting IP address to 192.168.112.25. But when I run ifconfig command it shows the following IPs: inet addr: 192.168.174.12 Bcast 192.168.174.255 ...
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2answers
3k views

How can I debug a problem with my network connection?

On one of my computers with Xubuntu 10.04 there is a problem with the network connection. How can I debug it? I tried the cable on my laptop (running the same operating system) and it worked, so ...
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2answers
621 views

How to keep overwriting the contents of a file instead of appending to it

How do I clear the contents of a file before writing to it? For example: echo one > filename.tmp # filename.tmp now contains "one" echo two > filename.tmp # filename.tmp should now contain ...
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1answer
2k views

How to do “netcat” relays properly so that I have more control?

How to use the netcat to have relays? Like following I tried but not working: cd /tmp mknod backpipe p nc -l -p 7007 0<backpipe | nc 192.168.1.101 9001 | tee backpipe I want to receive data on ...
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3answers
2k views

How to get list of computers similar to what is shown under “Network” in Windows

In Windows 7 when I click on Network I get a list of computers with the same workgroup of mine. But in Fedora when I click on Network I just get a single item Windows Network and I can't see the ...
3
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4answers
6k 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 ...
2
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2answers
2k views

What do the three values mean on network monitoring tools

Often in network monitoring tools there are three values for one measure. Ex rx: 2.0 kb/s 40 kb/s 10 kb/s Are these similar to how cpu load works, they are taken at different length time spans. ...
3
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1answer
464 views

Running a pbk file in Linux

To connect to my university's network, they provided me with a .pbk file. The file is made for windows of course and I have no idea how to use it in Fedora (I'm using Fedora 15)
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2answers
133 views

Use Linux to backup a MSWindows network?

Is it possible to use a Linux machine to backup everything on a Windows network? I would like to backup MS databases and also drives, so if a database record needs restoring, it can be done easily, ...
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3answers
10k views

How does traceroute resolve names?

While writing a script, I wanted to reference a machine by the computer name that I gave it (e.g. "selenium-rc"). I could not ping it using "selenium-rc", so I tried the following commands to see if ...
4
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3answers
4k views

Source code of netstat

Can I view the source code of netstat on my Linux machine?
4
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3answers
2k views

IPTables and transparent proxies

I have set up a local, transparent TCP proxy on localhost. I want to redirect ALL TCP traffic to this proxy, so it can handle it and nothing "leaks out," circumventing the proxy. I need to use ...
2
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1answer
204 views

Testing intranet network

This is probably a question already discussed here and there. I'd like to try to gathering here all the information. Suppose I'm on a machine connected to a network. This network has access to the ...
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3answers
3k views

How do I deploy Firefox Bookmarks for all Users in Network?

I have a bash-script for installing Firefox which is downloaded and executed from every client workstation in the network. The script is on the server and all workstations are running Ubuntu. Now I ...
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3answers
22k views

Output traffic on different interfaces based on destination port

My question is basically the same as Only allow certain outbound traffic on certain interfaces. I have two interfaces eth1 (10.0.0.2) and wlan0 (192.168.0.2). My default route is for eth1. Let's say ...
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5answers
1k views

How can I test whether connection to the given host/port is established in Bash?

Currently I'm using netstat for this: if netstat -an | grep ESTABLISHED | grep $address:$port > /dev/null; then # command fi Is there a more elegant solution?
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4answers
16k views

How to speed up X over SSH on a slow network connection?

Are there any specific recommendations on speeding up X applications over ssh on a slow network connection? In this specific case, I am accessing a server located in west coast from a laptop in east ...
0
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1answer
463 views

Private vlan concept (rfc 5517)

I'm learing vlan concept and came around private vlan rfc. I think that i understand the reason and implication of isolated domain, but i'm not sure that i understand the community domain. ...
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3answers
5k views

How should I determine the current network utilization?

I want to display the current network utilization (bandwidth usage) of one interface of a Debian box on a website. It is not supposed to be very elaborate or precise, just a simple number such as "52 ...
12
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3answers
12k views

Does mount always require root privileges?

I was under the impression that any sort of call to mount requires root privileges. But recently I was told "You should instead create appropriate entries in /etc/fstab so that the filesystems can be ...
4
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1answer
3k views

How do I recover/kill an SSH session after losing connection?

I lost my connection while I was logged via SSH into my university server. Classic. Now I can't log in since the session appears to be still running and I get the error "Too many logins for ...
0
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2answers
1k views

Dropbox doesn't connect properly on boot

I'm having a problem with Dropbox (version 1.1.35). When I first boot it takes some time before Network Manager connects to the WLAN. Then I see the Dropbox icon in the task list, claiming to be ...