Managing and using network connectivity on a unix system

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4
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2answers
108 views

Did this tutorial block pings to my server?

I am a programmer teaching myself linux admin stuff. I followed this tutorial to setup a firewall on a VPS. As a part of that tutorial, I block all traffic except for web traffic and SSH traffic. I ...
15
votes
1answer
29k views

Using ip addr instead of ifconfig reports “RTNETLINK answers: File exists” on Debian

I have a Debian system working as a wireless router with eth0 and wlan0. Now I added an additional network manually on eth1 with ifconfig: alix:~# ifconfig eth1 192.168.0.2 netmask 255.255.255.0 ...
0
votes
0answers
26 views

Command to see my current ip if proxy is applied only for a certain website

It might not be a relevent question here on so, but I tried on http://networkengineering.stackexchange.com and there are less users. So, I am not a networking guy and I have the next situation: I ...
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
0answers
19 views

Program like vnStat that filters for only external (Internet) traffic

I've been using vnStat to monitor the ethernet interface on a Linux computer, but found that it includes all local traffic. I do many file transfers from within the subnet which far exceeds the ...
1
vote
2answers
1k views

How to connect to an 802.1x wireless network via nmcli

I am able to connect to 802.1 networks via the nm-applet. I do not like doing this as I am running without a nm most of the time and I would hate to load up one just to connect to a wireless network. ...
4
votes
2answers
112 views

Elementary OS shows WiFi networks, but won't connect

In the top bar, clicking the network icon shows a list of networks. My school's network, which on Windows I would connect to, and then visit a login page in Chrome in order for it to work, shows on ...
2
votes
1answer
23 views

how to overcome conflict between 2 network cards - virtualbox ubuntu

I am running ubuntu 10.4.04 LTS as guest in virtualbox on OSX Yosemite. Unfortunatelly I seem to have the network configured wrong I followed this tutorials ...
9
votes
3answers
4k views

Can't access select https sites on Linux over PPPoE

My internet connection used to be a direct LAN connection to my provider. Back then, everything would load fine on both Windows and Ubuntu (dual boot). However, a while ago they started needing me to ...
4
votes
2answers
275 views

Send traffic to self over physical network on Ubuntu

I have a dual port ethernet NIC and let's say I have connected both ports in a loop and assigned the following IPs to the 2 ethernet interfaces: eth2 -> 192.168.2.1 eth3 -> 192.168.3.1 I want to ...
0
votes
0answers
39 views

Set the TCP window scaling option to 4 & the TCP window size to 65535 [closed]

I want all TCP packet (linux system) to be sent with: TCP window scaling option set to: 4 TCP window size set to: 65535 (0xffff). How I can configure my linux system to do that?
1
vote
1answer
37 views

Bonding two interfaces

I'm trying to simulate bonding between two interfaces eth0 and eth1. So basicly, I need these two interfaces to be on the same subnet. My question here is: How can I achieve this?
2
votes
1answer
35 views

Addresses overlaps

I was putting somes static addresses to my interfaces then it shows me this: 172.16.1.0 overlaps with FastEthernet 0/0 What does it mean when two addresses overlaps and how can we avoid it? EDIT: ...
2
votes
2answers
447 views

How do I route a spare network interface through an SSH tunnel?

I just bought a Raspberry Pi and I am wanting to route an ad hoc wireless network interface fully through an SSH tunnel that was created using another wireless interface. I want to do this so that I ...
1
vote
0answers
30 views

Linux - iptables - get YouTube streaming bytes usage

How do I get bytes usage using iptables for a particular IP, including YouTube streaming videos? Currently, I am using the following IP tables rules to get data usage by IP address: sudo iptables -I ...
3
votes
1answer
41 views

I can't ping my bond interface when simulating 2 WAN connections

I'm actually simulating 2 WANs connexions with Wanem (each one on a different VM), those are connected to my servers. What I need to do here is to create a bonding to improve my bandwidth. I've ...
11
votes
5answers
8k views

How to recover a shell after a disconnection

Am doing some work on a remote centos 5.6 machine and my network keeps dropping. Is there a way i can recover my hung sessions after i reconnect? EDIT: am doing some updating and installing with yum ...
1
vote
1answer
52 views

traceroute / mtr from multiple locations, How can we do it ? (Or alternate way)

I have a website, recently due to some network issue, Most of my customers are reporting slow loading time of my website. When I reported this to my DataCenter, they are asking me to send the ping / ...
0
votes
2answers
22 views

Unable to connect to certain IP address, but able to connect to other IP in same subnet

I'm running a 14.04.2 LTS ubuntu box in a DMZ with IP of 10.10.30.35 and I have the following network mystery. I'm trying to connect to another unix box outside the DMZ but in our internal network at ...
6
votes
3answers
6k views

ssh from host to guest using qemu

How do I setup ssh from the host to the guest using qemu? I am able to use port redirection when I boot the VM without any special parameters, as follows: /usr/bin/qemu-system-x86_64 -hda ubuntu1204 ...
1
vote
1answer
32 views

Unable to access another server over local network on Digital Ocean

I have two servers. Let's call them A and B. Both are running ubuntu server 14.04. B runs percona server. Now I do not have any firewall set-up on either servers still I am unable to connect to server ...
4
votes
1answer
92 views

SSH server listening on multiple ports with passwordless access not allowing connections to second port

I have my Synology NAS running an SSH server listening on the default port 22 and I set up passwordless authentication with a public/private key and a passphrase: From sshd_config: ...
0
votes
1answer
14 views

What happens to TCP when a write fails to enqueue with the device tx ring?

Lets say the device tx ring is full and you do a normal C non blocking write(fd, buff) to enqueue data in the TCP SND buffer. What happens when this fails? In UDP - the packet would be dropped but ...
6
votes
1answer
147 views

In Archlinux, it has a valid ip, but no connection could established

Later I changed a wireless router, and everything goes OK. Maybe there were something incompatible between the former one and the latter. Yet I can't get the reason. ...
0
votes
0answers
26 views

URXVT network issues

So yeah. Whenever I maximize URXVT my friend's computer's League of Legends client, while in-game, latency goes up to around 3,000. Wireshark, ntop and tcpdump do not reveal any outgoing packets ...
0
votes
0answers
11 views

How much of Linux's recent TCP bufferbloat remediation also applies to SCTP?

I am looking at rebuilding an existing communications sub-system within a shared-nothing cluster. The current message protocol is built on UDP but layers on reliable, in-order delivery and ...
0
votes
2answers
967 views

Need to add virtual interface in Suse Enterprise Server edition permanently

How can I add virtual interface in SUSE Linux Enterprise Server 11 permanently?
1
vote
1answer
25 views

Sharing the loopback interface across network namespaces

I'm interested in using a separate namespace for running a VPN client, so that every process I run into that namespace accesses the Internet through the VPN. That part I've managed to accomplish. ...
5
votes
3answers
21k views

how to ping & use specific network card

i have 3 network cards , 1 Lan (wired) , 1 wireless network card & 1 is wireless usb how do i ping from specific network card ? & how do i use specific network card for specific ...
0
votes
1answer
27 views

How to force nm-tool to update its DNS servers

Using Ubuntu 14.04LTS and having a problem with changing DNS. I can change servers in the /etc/resoolvconf/resolv.conf.d/base and head files and restart resolvconf using sudo resolvconf -u and it will ...
0
votes
0answers
11 views

IPvsadm, cannot get it to work at all

From my production server, I should make several connections (>50) to two different IP addresses. I am trying to load balance among these two IP addresses when making outbound connections so that the ...
2
votes
3answers
2k views

No route to host after upgrade to Fedora 19

I recently upgraded a system from Fedora 17 to 19. Now, I am not able to connect to any service other than ssh (perhaps a few others may be available but not sure) on it. Earlier this was not a ...
1
vote
0answers
21 views

Get Debian Wheezy netinstall to detect wlan

I'm attempting to install debian wheezy from the netinstall iso burned to usb. I'm trying to use a Belkin F9L1002v1. First time I attempted installation, I was notified of some missing firmware, so I ...
1
vote
0answers
33 views

Running a systemd service file after the network is up to bypass an OpenVPN default gateway

I would like to add a static route using a systemd service file on system boot. I have a DMZ network on a separate 192.168 class C network reachable via my default gateway. I also use OpenVPN to ...
3
votes
2answers
31k views

How to properly set up 2 network interfaces in CentOS (running in VirtualBox)?

I have a VirtualBox machine running CentOS 6.5. I've created 2 network adapters for it in VirtualBox's networking settings for the machine. The first is NAT which I want the guest to use to connect to ...
0
votes
1answer
36 views

What does “network interface” mean in /etc/network/interfaces, ifconfig and iwconfig?

/etc/network/interfaces is a file configuring network interfaces, and ifconfig and iwconfig are commands operating on network interfaces. I saw the logical name for a network interface they use can ...
0
votes
0answers
16 views

Snort alerts analysis (web interface)

I have a question about Snort (or maybe any other IDS/IPS, any working solutions would be ok). The goal is to set up some web interface providing a way to view the whole TCP stream packets of each ...
-1
votes
0answers
17 views

Is netcat or socat zero copy

netcat or socat could run like a broker in messaging systems. For example: a one-line forward server socat TCP4-LISTEN:www,fork TCP4:www.domain.org:www Are they zero-copy under the hood?
1
vote
2answers
31 views

How can I bring up up a non-boot (ONBOOT=no) network interface with iproute2?

Have a network interface that does not come up on boot-up: [belminf@tito ~]$ grep ONBOOT /etc/sysconfig/network-scripts/ifcfg-enp0s3 ONBOOT=no I know I could do the following for DHCP: ...
1
vote
2answers
164 views

Linux lock down route to avoid changes to the default route

I have a problem that every time I connect my Android phone with USB tethering it hijacks my computer's internet connection. Even if the phone's WIFI is off. I try to manually remove the default ...
1
vote
1answer
52 views

ifconfig not showing ip address under eth0

Usually when I connect my raspberry pi to my laptop using an ethernet cable, the ifconfig command in each computer would show the ipaddress of each computer under eth0. I recently got a new raspberry ...
3
votes
1answer
2k views

Accounting for /proc/net/dev reported traffic

I noticed that according to /proc/net/dev I am constantly receiving around 6Kb/s on my wireless usb interface. But I can't account for anything even close to that with the individual connections that ...
1
vote
1answer
181 views

ubuntu 13.04 wifi lost connection - how to get it work again? (broadcom4313)

I am new to ubuntu, meaning I have a lack of funded knowledge and skills, but I hope I provide any necessary information you need to know for solving the problem. My problem is that I moved to a new ...
0
votes
1answer
19 views

SUSE 12 setting up virtual network interface

I'm struggling to setup virtual eth interface on Suse 12 When I run: ipconfig eth0:1 10.0.0.2 netmask 255.255.255.0 Output from ifconfig is as expected: eth0 Link encap:Ethernet HWaddr ...
1
vote
0answers
24 views

List all layer 3 protocols available in my system?

I am studying the OSI model and I have some doubts. How do I list layer 3 (OSI) protocols available/running in my system? Can I monitor them? Can I access to them (other than IP) from an programming ...
1
vote
1answer
20 views

how to use tc with htb on arch-linux

I'm trying to use this tc script on my arch box. Specifically, the first line, roughly equal to tc qdisc add dev eth0 root handle 1: htb default 3 fails with RTNETLINK answers: Operation not ...
0
votes
1answer
52 views

-bash: auto: command not found

I'm going to config my network interfaces and run this command: auto eth0 but it returns -bash: auto: command not found. It seems I've missed something which I don't know. Any idea? What should I ...
1
vote
2answers
2k views

Split DNS (bind9), match-clients any doesn't work?

I've been fighting with this for the last few days. A few of my entries have external and internal IP's. My internal network is 10.0.0.0/8. When I nslookup pc1.clase.net internally it responds with ...
4
votes
1answer
2k views

Networking and Samba from a quest OS running on qemu

I'm trying to test some software on a big endian system to ensure compatibility. My plan is to use qemu on Ubuntu 12.04 to emulate a MIPS system. So far I've been able to create the quest system ...
1
vote
0answers
17 views

Change of Network Interface using Metrics

I want to achieve dynamic interface change between eth0 and wlan0, one solution I am looking into is to change interface metric. Different than this question, I don't want to make any change to ...