Managing and using network connectivity on a unix system

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4k views

Centos 6.3 can't resolve hostname of network drive while others can

I have a network drive (external network) being used as media storage for a media server running on my router. I'm trying to switch the media server to my Centos 6.3 machine so I can take advantage of ...
13
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4answers
6k views

How can I find which process sends data to a specific port?

I have a service, keeping a certain port open. I'm getting data to it, that I neither expect nor want to get, and I'm trying to pin-point the source of this data. So how can I find which process that ...
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0answers
727 views

eth0 not getting disabled after setting up br0 interface

On debian squeeze, I setup a bridge based on eth0. My /etc/network/interfaces is # The loopback network interface auto lo iface lo inet loopback # The primary network interface #allow-hotplug eth1 #...
2
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1answer
674 views

Excessive retransmissions on Ethernet

The CSMA/CA variants of Ethernet handle excessive failed transmissions due to repeated collisions by dropping the current frame and relying on upper layers for retransmissions: After 16 attempts ...
2
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1answer
279 views

Madwimax: modem connecting but no internet

I'm using the madwimax package to connect a Samsung USB modem to the internet. It has worked well before, on previous versions of Ubuntu, but now that I upgraded to Ubuntu 12.10 I have had problems ...
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2answers
2k views

“PING” an AP to see if it's alive? (Before associate with it)

I would like to detect if a certain AP address is alive, i.e. by "PING" its SSID or MAC address (both known). What program can I use to achieve that? I'm making a simple script that run as root. (I ...
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2answers
4k views

Debian 6 internet problem: ifconfig doesn't show eth0

I just installed 64-bit Debian 6.06 on my ASUS K53S machine and internet is not working... Wireless is working fine. NetworkManager is doesn't show any wired connections and ifconfig in the terminal ...
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1answer
272 views

Can I set up linux to accept a dial up connection from my old windows95 laptop?

I've got a really old laptop running Windows 95, and I'd like to be able to connect it to my home network. It doesn't have an ethernet jack, nor a usb port. It does have an internal dial up modem ...
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6answers
90k views

How can I monitor all outgoing requests/connections from my machine?

My machine is a server so I want to ignore connections being made to my server (e.g. when someone visits my website). I want to see only connections/requests being made by my server to other places. ...
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3answers
3k views

Monitoring HTTPS traffic using tcpflow

I would like to use tcpflow to monitor https requests. I have read tutorials on how to monitor http traffic but when I connect to a host using https the output is garbled. I am using tcpflow in the ...
4
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1answer
1k views

Problem with path MTU discovery over pppd

I'm having an issue with pppd doing PPPoE on CentOS 6.3. The CentOS system is a dedicated router/gateway which performs NAT (both directions) and various packet filtering. It has separate NICs for ...
2
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1answer
923 views

redirect web server with no-ip and port forwarding in livebox

I want my Apache web server running on a Livebox (home router appliance running Linux) to be accessible from the Internet (WAN). I installed and configured the application noip2 on my Ubuntu PC. ...
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2answers
3k views

lts is there a way to enable sleep mode and wake on lan?

I was wondering if it were posible to make my server go to sleep after a set period of time, but still be listening for lan requests. I use my server as a media server that might get used 3 or 4 hours ...
2
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3answers
207 views

Connecting Debian webserver to network

I am currently running a webserver with Debian 5.0.2. It has been working (more or less) fine for the past 2-3 years but recently it went down due to some power-outage. Ever since I have brought it ...
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4answers
1k views

Check if the residence's connection has internet access

I'd like to be able to test if I have access to the internet. My computer is connected to the residence internet connection. I thought of using ping like this: ping -q -w 1 -c 1 `ip r | grep default |...
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5answers
18k views

What's the easiest way to find an unused local port?

What's the easiest way to find an unused local port? Currently I'm using something similar to this: port=$RANDOM quit=0 while [ "$quit" -ne 1 ]; do netstat -a | grep $port >> /dev/null if ...
2
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1answer
2k views

Terminal server (ser2net) to configure new HP procurve switch

Switch: HP ProCurve 2910AL-48G - J9147A This switch is brand new straight from HP. Anyone familiar with ser2net for creating a terminal server to connect from usb>serial>console port on a HP ...
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2answers
3k views

Is there a faster interface for info from /proc/net/tcp?

Given a linux TCP socket's inode (obtained via /proc/<pid>/fd), is there a faster way to look up the information that I can get from /proc/net/tcp about this socket? I have written a ...
4
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4answers
13k views

CentOS 6 - nameserver entry in resolve.conf resetting after restarting network services?

In /etc/resolv.conf, I've changed the nameserver line to a new IP address. After saving and exiting, I run service network restart. I then go open /etc/resolve.conf again and see that the IP address ...
3
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2answers
658 views

Connecting to wireless router

According to this manual I tried: $ iwconfig lo no wireless extensions. eth1 IEEE 802.11bg ESSID:"g\xC6isQ\xFFJ\xEC)\xCD\xBA\xAB\xF2\xFB\xE3F|\xC2T\xF8\x1B\xE8\xE7\x8DvZ.c3\x9F\xC9\x9A" ...
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1answer
849 views

Setting mobile broadband connection in Fedora 17

I am using a Dell Precision M4500. I've realized that there is a SIM slot underneath the battery slot, I suppose it is for using mobile broadband access. I am usually connecting to the internet ...
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2answers
16k views

No network connection in CentOS 6.3 Minimal under VMWare Player

I'm trying to replicate in VMWare Player the exact same conditions I have under my Dedicated Server for testing purposes. Now, the thing is that that when I try to install something, or ping http://...
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0answers
1k views

Send print job to printer immediately without queueing, aka increase print performance

I have a ruby/rails web application, one action of which sends PDF files that have been generated by the app to a Xerox 4127 printer on the network. This is accomplished via shelling out and running ...
1
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1answer
2k views

Extract binaries from pcap using command line (script)

As the title says, I'm looking for a way to extract binaries from PCAP's using the command line. I realize it is possible using Wireshark -> File -> Export -> http objects etc. But tshark doesn't seem ...
3
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4answers
3k views

Tools that monitor the network bandwidth based on IP?

In a networked environment, such as SOHO, is there any tools that can monitor the network bandwidth usage based on the computer's IP or mac address? So that we can know which user has the highest ...
5
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1answer
560 views

Using source routing (LSRR) - any ideas?

What I want to do is conceptually very simple, but I can't find any information or help about how to go about doing this. Basically, I want to configure my networking to use source routing (LSRR). ...
0
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1answer
1k views

pcap and raw socket [closed]

I want to develop an application (module or user-level if possible) to create a raw socket in RHEL stealing all level-2 packets directly from kernel (without being routed or handled by other open ...
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2answers
2k views

Best way to find out what Linux Version is used on a Webserver

Is this feasible? Can I find out which distro is used to host specific webpages? Whois doesn't have info for this.
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2answers
615 views

How to find transmission speed?

Two host machine's one as a client and other as a server, i am testing udp load-test in these two machines.Machine Ethernet speed is 100 Mbps but i want to send 30000 packets each of 512 bytes at 1 ...
2
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1answer
1k views

Changing service startup order

I use wpa_supplicant to configure the wireless connection. Now I have a problem in that the network service starts before wpa_supplicant so this happens: Bringing up interface wlan0: Determining IP ...
3
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2answers
799 views

Meaning of log entries from an iptables configuration

My router has Linux as its OS. The system log has a lot of rows about iptable and klogd that I don't understand, could someone explain them to me? The iptables setup: iptables -t nat -A PREROUTING -...
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0answers
250 views

No ports can be found using port scan

Problem: I have a laptop and a server (Home-Server) with fc17. They are both using the desktop environment. I am trying to set up a VNC server on Home-Server so that I can set everything up without ...
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3answers
8k views

How to tell who is connected via vnc to my machine?

How do I check how many vnc connections or different users are currently connected to my machine? Only through wireshark? And how do I kill any other users connected through vnc?
5
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3answers
5k views

DNS Master vs Slave and Primary vs Secondary

I'm a little confused about the difference between a "secondary name server" and a "slave name server" and a "primary name server" and a "master name server"   I understand that a slave name server ...
0
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4answers
9k views

How can I reinstall Network Manager after uninstalling it?

I am running a version of RHCE6 on my laptop, and lately I've been trying various stuff about network configuration through command line. Last night, I tried removing the NetworkManager using yum ...
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0answers
376 views

How can I renew lease when it kept printing eth0 lease expired x seconds ago?

My guest VM cannot get an IP address from my host. It keeps printing: eth0: lease expired x seconds ago I've tried to start dhclient -r and dhclient and restart eth0 to no avail, see here for more....
3
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2answers
1k views

Set the preference for sending packages through an specific network device

I have SL 6.3 installed on two machines. Machine A is a workstation and has two interface eth0 and wlan0. Using eth0, it is connected to Machine B (public facing server) with static IP address. Both ...
7
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1answer
1k views

What is “link beat”?

I have a Linux 2.6 box that uses ifplugd to bring up the network. While initialising, the logs say, "Initialisation complete. Link beat not detected." and then it goes into releasing the present ...
9
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3answers
3k views

How do I find the process generating a lot of network traffic?

My machine is generating a lot of network traffic, all from the same source port, with many different destinations (found this out by running iftop -P, and from my router's logs). How do I find the ...
0
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0answers
692 views

Changes made to ifcfg-wlan0 doesn't seem to make a difference

I am running RHEL6 on my laptop. The wireless adapter configuration file ifcfg-wlan0 didn't come by default under /etc/sysconfig/network-scripts. So I created it myself. The problem is, whatever ...
2
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1answer
382 views

Configuring Wireless Network

After a long struggle I finally seem to have installed the non-free wireless firmware for my wireless NIC. I'm trying to set up a file server, so I want to configure the network to be static. Would ...
3
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2answers
5k views

Driver for Intel 2200BG wireless network card

I'm trying to make work my wireless network card Intel 2200BG in my laptop Acer Travelmate 4002WLMI. I tried so far: $ sudo lshw -C network *-network:1 description: Wireless interface ...
6
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1answer
5k views

nsswitch.conf versus host.conf

Suppose that /etc/nsswitch.conf file contains hosts: files dns and /etc/host.conf file has order bind,hosts then in which order the system would use /etc/hosts and DNS look-up to resolve a host ...
2
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2answers
17k views

Where could I find the ifcfg-eth0 file?

I am using RHEL6, but I could not find the Ethernet interface configuration file ifcfg-eth0 under /etc/sysconfig/network-scripts. Issuing ifconfig -a shows that eth0 does exist. Could it be that the ...
5
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1answer
11k views

What is the difference between virbr# and vnet#?

I am running KVM on RHEL6, and I have created several virtual machines in it. Issuing ifconfig command to the host system command line shows a list of virbr0, virbr1... and vnet0, vnet2... Are they ...
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1answer
3k views

Network Interface Names output from ifconfig

So this has been driving me nuts for a good couple of hours, so I thought I'd ask about it here (let me know if there's a better forum for this question). I have a CentOS Virtual Machine on ESXi. I ...
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0answers
139 views

Unable to access internet if wireless enabled

The following is my route output. eth0 is my wired network and eth1 is my wireless network. Only wired one has access to internet. If I enable wireless, I am not able to access internet, it tries to ...
2
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0answers
787 views

Missing Firmware for Wired NIC on Debian

I'm trying to install debian 64bit from a debian live image using YUMI on my usb drive. I'm installing it on an Inspiron 6400, and there is missing firmware. I can't connect to the internet whatsoever,...
2
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2answers
3k views

Why doesn't eth0 get an ip address when set up in a bridge?

I'm trying to understand how dhcp for IPv4 is used with bridging. eth0 is configured to be in br0. This is working just fine but only br0 gets a dhcp lease, while eth0 doesn't. Both are configured ...
1
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1answer
696 views

How to get the cloned guest connected to the Internet?

I made a clone of a VM(running a version of Centos 6) on KVM, but the clone wouldn't connect to the Internet. Issuing ifconfig shows no interfaces but the lo. Interestingly, the original system can ...