Managing and using network connectivity on a unix system

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No internet access for system services; however, browser access works

Unable to reload repos via apt-get, aptitude, or synaptic. Dropbox does not connect or sync. Pithos does not connect to pandora.com. Chrome and Firefox browsers do work fine. I have been unable to ...
6
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2answers
23k views

eth0 not being configured automatically

When I start an ubuntu 12.10 instance, eth0 is NOT getting configured. davidparks21@MySqlDB:~$ cat /run/network/ifstate lo=lo When I manually edit ifstate and add eth0=eth0 and service restart ...
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0answers
157 views

Modifying resolv.conf when when bringing network interface up on system startup

My Linux box currently has a network interface that allows me to connect to a network on a different subnet. I've achieved this by modifying the routing table when the network interface is brought up. ...
5
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1answer
2k views

tc on bridge port

I have a 4 port bridge: root@Linux-Switch:~# brctl show bridge name bridge id STP enabled interfaces br0 8000.000024cd2cb0 no eth0 eth1 ...
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0answers
1k views

I have a route to the network but from the traceroute output it doesn't leave the server

I have an HP-UX box and I'm trying to determine why a host can't be reached. I'm trying to reach the host 10.32.13.146 root@hp-ux:/root # traceroute -I 10.32.13.146 traceroute to 10.32.13.146 (10.32....
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4answers
43k views

Ubuntu: How to configure DNS servers in /etc/network/interfaces correctly for resolvconf?

All examples I have seen of configurations (/etc/network/interfaces) showed that you configure an interface and then underneath that gave the dns-* lines such as: auto eth0 iface eth0 inet static ...
0
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1answer
143 views

What are the other congestion control algorithms specially designed for lossy Wireless Networks like LTE and WiMax?

I am trying different congestion control algorithms for getting maximum throughput and minimum delay across my setup for TCP flow.Please suggest other available algorithms apart from Veno, ...
0
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1answer
118 views

Problem in connecting server to Internet

I just have setup a Linux server. But currently I am having problem in connecting to the outside world. I am not able to do wget,apt-get or ping. Here ar some relevant details: $ping google.com ping:...
6
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1answer
292 views

Ways to give a process “idle” network priority

When I'm playing a game, I don't want Dropbox taking hogging my network connection. I have been able to noticeably reduce my latency by turning it off while playing. The same is true to a lesser ...
1
vote
1answer
670 views

How to troubleshoot high kernel time (high network usage; high interrupts)

I've noticed that I have high kernel time when doing a lot of network traffic in Linux. I also noticed that 45% of my CPU is spent doing interrupts. How can I further troubleshoot this?
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1answer
18k views

Cannot reach outside network or IP after upgrading to Ubuntu 12.04

I am running Ubuntu 12.04 on my server but since the upgrade from 10.04 I can no longer reach any outside sources of the server. I can SSH into the box, but from inside here I can not reach anything. ...
0
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1answer
4k views

OpenSuse 12.3 keeps renaming network interfaces?

After installing OpenSuse 12.3 (x64) on a server box with a single (onboard) NIC (assigned to eth0), all works fine so far (static IP, static route, no "Network Manager" - just the good old way). ...
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0answers
213 views

To what extent does LXC manage configuring the network interface in a container?

In the LXC config file we can specify an IP address for a container: lxc.network.type=veth lxc.network.link=br0 lxc.network.ipv4 = 10.1.0.35/16 lxc.network.flags=up lxc.network.hwaddr= 00:16:3e:24:26:...
2
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0answers
324 views

Network in LXC not forwading through a bridge

I've got an LXC container, on the host I've got a bridge between the LXC container and eth0. The LXC container can ping it's Host 10.1.0.5, but can't ping the gateway of 10.1.0.2. The host is able to ...
2
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0answers
3k views

Using a bridge, an LXC container can't ping router, but the host OS can

I've got a virtual machine running under virtualbox, and in that virtual machine I've got an LXC container I'm trying to bridge to virtualbox's NAT interface: ------------- ----------- -----...
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vote
1answer
166 views

Communication to device is lost when network starts on boot up?

I have an application that opens a socket on port 4444 to a device (/dev/linkToDevice). The "linkToDevice" is a link to ttyUSB0. The application is a c++ program of which is now a daemon and runs at ...
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2answers
3k views

Use eth interface to connect to a router and wlan for the internet

I am currently trying to configure a router to which I connect to (to its web interface) using an Ethernet cable through the eth0 interface. That router doesn't have access to the internet. Now, I ...
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2answers
4k views

Routing for multiple uplinks/providers

I have a PC with two internet connections. The first one is an Ethernet interface to connect to my local network and access internet via my router. The second one use a GSM modem to connect with ppp. ...
3
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2answers
7k views

Extra bridge interfaces get added automatically

I have a bridge set up between eth0 and br0, the bridge works fine, but sometimes, for unknown reasons and circumstances, I keep getting these off vethXXXXXX interfaces added to the bridge. When this ...
0
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1answer
212 views

Make application listen to hosts under a different gateway

Network Structure A typical college network. Different Hostels connected through LAN. All hosts in a hostel use the same gateway. I can directly communicate to hosts in other hostels using their ...
38
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8answers
13k views

Block network access of a process?

Is it possible to block the (outgoing) network access of a single process?
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2answers
2k views

How to transparently monitor SSH access/network traffic in Gentoo/general linux?

What's the most effective way to monitor SSH access in Gentoo Linux? My Gentoo box is operating locally behind my broadband router. I have SSH port forwarding on the router and a DNS entry pointing ...
1
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1answer
88 views

Enforce strict outbound ports (or ranges) for protocol

Is it possible to narrow the allowed range of outbound ports that can be used for a specific protocol (e.g. HTTP(S))? I understand that, by default, the system will randomly allocate any available ...
1
vote
3answers
593 views

Packet analyzer to intercept and filter incoming traffic before any client app

I am curious if most Linux distros make it possible to intercept incoming network traffic as soon as it enters the system and filter its content based on some rules before any other client can use it ...
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0answers
199 views

No AirPlay in XBMC on EeePC (Debian)

I have a Asus EeePC (900 model I think) and I've installed Debian 6.0 on it. I've managed to get WiFi working on it and I've installed XBMC. It's working with our NAS drive on the network but for some ...
2
votes
1answer
97 views

Custom application running on embedded device - do I need to register my listening port in /etc/services?

I have written an application that will run on an embedded device. The installation is very minimal and uses busybox and not many other things. Part of the software includes a listener thread that ...
0
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1answer
200 views

Local host always being added to /etc/hosts.deny when trying to SSH

I have a rather odd problem with my server. For some reason the local hostname for my workstation keeps getting added to the /etc/hosts.deny and when I try to SSH I get: ssh_exchange_identification: ...
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0answers
768 views

Tools to find OpenVPN UDP packet corruption

Are there Unix tools to troubleshoot UDP packet corruption? I'd like to avoid writing my own... I think ping might report when a packet is corrupted, but it doesn't really seem to have options ...
0
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1answer
170 views

Samba connection slowness after ip change

we have encountered with a problem when we chaged the samba server's ip address. There are so many OS varies from Windows,GNU/Linux, Solaris and IBM. The samba server is running on SOlaris. And all ...
26
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1answer
853 views

Why does it take up to several minutes to clean a listening TCP port after a program dies?

If I kill a program that is listening on a TCP port, it takes up to several minutes until the port is reclaimed by the system and usable again. I've seen several Q/A mentioning this phenomenon, but ...
5
votes
1answer
3k views

Very slow response from localhost when pinging

Networking is working fine on my gentoo machine. One connection is made, everything works fine with normal speed. But it is slow to wake-up : starting up connection is taking time. Even pinging local-...
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1answer
11k views

Use of /etc/sysconfig/network-scripts/ifcfg-eth* files

What's the use of /etc/sysconfig/network-scripts/ifcfg-eth* files ? In some cases ifconfig lists the interface eth0 but I don't find the corresponding ifcfg-eth0 file whereas in other instances if I ...
5
votes
2answers
6k views

Use an USB tethered phone as network adapter

I am running CentOS 6 and was able to tether my HTC phone using a proxy called proxoid . This allows me to redirect HTTP. But how do I redirect the entire TCP traffic, e.g. if I need to setup openvpn ...
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votes
2answers
5k views

Cannot access to web server, but can ssh to it

I have a Ubuntu server but there are some weird things I can't understand. I cannot ping to the server via IP address, but I can ssh to it. I can access to apache server inside the server via command ...
2
votes
1answer
547 views

Solaris 11: How to use ILB to create HA loadbalancer across two backend servers?

I'm attempting to use Solaris 11's ILB to create a loadbalancer across two backend DNS servers. Here's my requirements: Two external IPs: .XXX.YYY, .XXX.ZZZ - these are the DNS IP's that our clients ...
3
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2answers
4k views

Guest OS Ubuntu 12.04 no network connection

Recently added a new *.VDI image with Ubuntu 12.04 to my existing VirtualBox. The machine hangs with a "Waiting for network configuration" error, eventually times out after 60 seconds and boots in ...
2
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2answers
163 views

Remote access SSH problem

I have been asked to setup a lab with 1 PC (fedora 18 OS) and 4 SGI (IRIX 6.5 OLD OS). I am using a switch to connect them to university's network, and I asked tech guys to assign static IPs to them. ...
16
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4answers
3k views

Is there a top-like command that shows the network bandwidths and file accesses of running processes

For example, we'd like to see: PROCESS IF TX RX FILE(regular) R/W prog1 eth0 200kB/s 12kB/s -- -- wlan0 12kB/s 100kB/s -- ...
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2answers
5k views

Unable to connect to remote host using ssh

I have recently installed Fedora in my system. But I am facing some problem in ssh login from remote machine. I am able to login in that system but every time its requires me to login using GUI in ...
3
votes
1answer
311 views

Is there a way to renice the network stack?

I have an ARM Linux board that is a router to 16 other boards. When all these download their updates via the router, the network routing effort starves the user space so that a software watchdog (and ...
5
votes
2answers
5k views

Network naming on Arch Linux

I've just installed Arch Linux on my old PC, to do the installation I used wifi-menu wlan0, now I've reboot but if I type: ifconfig wlan0 up I have as a result: wlan0: ERROR while getting ...
2
votes
1answer
4k views

How to monitor other nodes to get RSSI?

I need to measure RSSI between two peers of nodes in same network. If I have these two information: SSID for their network. IP for the target node to get the RSSI regarding it. So I found this ...
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2answers
2k views

Why TCP TIME-WAIT State is present at both ends after a connection termination?

I am reading how the TCP states work and especially the connection termination part. All of the books or online material I read, shows that for the termination procedure these states are followed ...
3
votes
3answers
199 views

How to use a “hardware key” to control Linux networking

Sometimes I have trouble controlling myself while in front of the computer and I tend to procrastinate a lot doing Internet surfing. Fortunately I do not need Internet for most of my work. So I would ...
1
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1answer
808 views

No DNS on Debian wifi after unplugging the DNS cable

I have installed wheezy Release Candidate 1 to my old laptop (Benq Joybook A52) right now, and I have some problem with my wireless card (Atheros 5006). It can actually see the wireless networks, I ...
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2answers
23k views

Getting current TCP connection count on a system

Instead of doing wc -l /proc/net/tcp, is there a faster way of doing it? I just need a total count of tcp connections.
3
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2answers
825 views

tshark dump only when string is matched

I'm working on a web capture script where I only want to dump the traffic if the HTML body or URL contains a string defined in a .txt file. Here is my tshark command which dumps src ip dest url (HTTP ...
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1answer
3k views

With two interfaces, how can I make one the default route and the other an alternate?

I have wired connection to intranet / lan of my work (with proxy) and one wireless without proxy that doesn't have access to the office lan. (Like Guest Wifi) My idea is to route all traffic to eth0 ...
2
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3answers
3k views

Can conky monitor other Linux computers on the network?

I know conky can monitor my personal computer, but can it monitor the other Linux servers I have on the network? I'd like to see data on CPU and memory usage and some critical processes each server ...
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0answers
3k views

Openswan established NATed tunnel but, I can't ping remote end's lan PC

I am establishing site to site tunnel. 192.168.2.0/24===10.103.6.40<10.103.6.40>---10.103.6.1...10.103.6.29<10.103.6.29>===192.168.1.0/24; Local ip: 10.103.6.40 Local lan: 192.168.2.0/...