Managing and using network connectivity on a unix system

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2
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1answer
2k 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? ...
3
votes
2answers
3k views

No, I don't want persistent net rules

I have a bootable Linux memstick that I use on a lot of different PCs (but all of the same model and configuration). Trouble is that udev is renaming the eth interfaces so that what was eth0 on the ...
5
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2answers
1k views

What's the next step in troubleshooting this wireless connection failure?

I just installed Ubuntu 10.04.3 to dual-boot with Windows. I can connect to the Internet using a wired connection, but not through wireless. The first time I booted, the wireless notification bar ...
4
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1answer
5k views

CentOS doesn't know what the internet is

So I've done my share of investigating this problem... I just recently created a CentOS 6 VM on my LinuxMint box using VirtualBox. I left all the recommended values the same upon creation (8GB HDD, ...
4
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1answer
150 views

connect() blocked for 3 seconds after a lot of success connect()

I am writing a client-side application which connect() to a server and close it in a for loop. The connect() is done in blocking-mode, and I found that some connect() call will block for about 3 ...
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2answers
327 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 ...
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2answers
459 views

UDP NAT Punching

I have the following two problems. Please help me to solve them: In symmetric NAT, as I know, the local hidden node (behind the NAT) must initiate connection in order to create a window in the NAT ...
2
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1answer
644 views

How can I update the OUI list used for Netdiscover?

Netdiscover keeps showing a lot of "Unknown vendor" devices, when I generally can find the vendor pretty quickly via Google. Is there any way to manually update whatever OUI list Netdiscover uses?
3
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0answers
618 views

Wireless rtl8187 freezes intermittently

I am using a wireless USB ALFA 036H. Linux Mint (32-bit) recognizes it without any drivers but it stops downloading/uploading and I have to reconnect to get it to work again. I tried to find a ...
2
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2answers
1k views

Checking the type of NAT

I have read that there are many types of NATs available like symmetric NAT, full-cone NAT, etc. If I am behind a NAT, is there any way to find out the type of NAT behind which I am currently working ...
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0answers
751 views

Mount Freecom Classic SL Network Drive (NDAS) in Ubuntu 11.10

Both the Network Drive and the Ubuntu machine are connected by Ethernet to a Linksys WRT54GL router (192.168.1.1). To access the Network Drive in Windows, I installed the NDAS software and mounted ...
2
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1answer
634 views

Is vnstat reporting accurate?

I'm checking the stats of a busy site that host mirror downloads. I installed vnstat on the machine and after a few days i saw the number 125.25 Mbit/s or using -ru 0 15.29 MiB/s I'm extremely ...
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2answers
1k views

Why does my USB wireless network adapter disconnect every few seconds?

I don't have experience with drivers and other things. After installing Linux Mint 11 on my machine (I did a dist-upgrade), everything seemed to be great -- I didn't need to install any drivers. After ...
2
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1answer
716 views

VirtualBox host-only network suddenly stopped working , no interface available inside

I'm unable to setup host-only network in virtualbox suddenly , please see my screenshot , there's no entry in "Name" comboBox
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2answers
425 views

Network file sharing with freebsd server

I have a freebsd server at home. I also have other OSes like linux and windows connected to the same network via WLAN (wifi). I want to be able to share stuff (what ever I download ;)) on my FreeBSD ...
2
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1answer
1k views

Atheros ar8151 driver for kernel 3.x (fedora 16)

Yesterday, I installed Fedora 16 and found no wireless connection available. Then I found the ar81family driver But it seems like it does not work with kernel 3. I changed the makefile to ignore ...
3
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1answer
172 views

Doing nmap on a network

I used nmap to scan all the ports in the hosts in a network by using the command: $ nmap 172.31.100.0/24 What I found is that it showed the following in the result: Nmap scan report for ...
6
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2answers
569 views

How can I test the current carrier state for an ethernet adapter in Linux?

In Arch Linux, how can I check if a network device (say eth0) has a carrier signal present?
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3answers
4k views

How I can know the IP address of other users logged at the same remote machine?

I can see the names of other users on the remote machine with the who command... I'd also like know the IP address of those users... I was trying with the commands /sbin/ifconfing and netstat but I ...
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0answers
496 views

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
221 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
777 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 ...
1
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1answer
422 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 ...
0
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1answer
644 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 ...
3
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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
68 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 ...
2
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1answer
406 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 ...
6
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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 ...
9
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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
votes
1answer
136 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 ...
1
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1answer
6k 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 ...
3
votes
2answers
2k 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 ...
3
votes
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 ...
1
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1answer
574 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 ...
0
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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
votes
1answer
399 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 ...
2
votes
1answer
12k 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
votes
2answers
295 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 ...
1
vote
1answer
256 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
votes
1answer
881 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 ...
5
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1answer
5k 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 ...
2
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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 ...
4
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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
112 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
514 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 ...