Managing and using network connectivity on a unix system

learn more… | top users | synonyms (1)

31
votes
7answers
42k views

What DNS servers am I using?

How can I check which DNS server am I using (in Linux)? I am using network manager and a wired connection to my university's LAN. (I am trying to find out why my domain doesn't get resolved)
0
votes
2answers
864 views

Route wlan0 to openVPN tunnel and rest to eth0

I'm having problems to create route/iptables rules for following configuration: I have an openVPN server (tun type) running on my raspberry machine at home At work i have company pc (behind proxy) ...
5
votes
1answer
347 views

Unable to configure eth1 and eth2 properly on Ubuntu

I am completely new to network administration, and so am finding things a bit tough. I have a machine, whose 1 interface I have to set to the subnet 10.0.20.0/24, another to 10.1.0.0/24 and a third to ...
2
votes
3answers
67 views

One-liner for getting an IP address of an internal DNS name?

I have an internal DNS name for which I'd like to get the IP address. Is there a nice Bash one-liner I can issue to convert internalip1.mydomain.com into 10.10.10.10?
0
votes
1answer
25 views

Connect through different interfaces to the same server

i have two pppoe interfaces - ppp0 and ppp1. I would like to reach the same server on both interface. I added the desired ip address to the route table: route add 10.88.40.13 ppp0 And I could ...
2
votes
2answers
713 views

keep losing IP with dhcpcd

I have an Arch Linux install in a VirtualBox VM, and as I'm working all of a sudden, it will lose it's dynamic IP address. When this happens, if I check on the status of the dhcpcd service it says ...
19
votes
7answers
18k views

How to get my own IP address and save it to a variable in a shell script?

How can I get my own IP address and save it to a variable in a shell script?
5
votes
2answers
2k views

Cannot connect to any localhost connections

I'am using Centos 6.5 with latest updates. My problem is that whenever i try to connect to some local service it just hangs for example: wget wget 127.0.0.1 --2014-03-11 12:43:42-- ...
2
votes
2answers
28 views

mknfsmnt fails with “System call error number -1”

This system is part of a cluster and the other node mounts the nfs share successfully. This is currently the active node which means it has a secondary service ip address. I think this is related to ...
0
votes
0answers
39 views

How can I configure multiple tap interfaces for a single KVM virtual machine

I am trying to setup a VM using Linux KVM for a F5 BIG-IP VE deployment (used in a lab) ...
2
votes
1answer
42 views

make my Debian laptop switch autoamtically to a backup connection

I have a laptop with Debian OS installed under it. It is initially connected to the internet using an Ethernet cable (via a modem) and I want to automatically switch to a backup wifi connection (which ...
1
vote
1answer
23 views

I need dhclient to flush IP address/routes when link goes down

I am running one Ubuntu Server 14.04 with network configuration using /etc/network/interfaces and so ifup/ifdown scripts. I realised that if I configure one interface in DHCP mode, then I unplug the ...
1
vote
0answers
14 views

Transport keyboard/mouse events to a keyboard/mouse-less remote host

I want to send keyboard and mouse events from a small ARMv7 computer board to a remote one, which has no keyboard nor mouse. I'm planning to send these events on a locally implemented CAN bus. The ...
1
vote
1answer
36 views

How do I run a program without network access? [duplicate]

I am making a program that scrapes information from some web services. I want to test how my program reacts when it can't reach the web service, like if the web service is down or if the local ...
0
votes
0answers
19 views

how do I disable the firewall through YaST?

The fine manual states: The Start-Up section defines how your firewall will start. You can either have the firewall start automatically when booting (recommended), or you can set the firewall ...
4
votes
1answer
64 views

what is “rfc3442-classless-static-routes” in /etc/dhcp/dhclient.conf

I am trying to debug DHCP on my laptop (I am using dhcping and dhcdump to see what the DHCP server sends back). Following is my /etc/dhcp/dhclient.conf. option rfc3442-classless-static-routes code ...
1
vote
1answer
590 views

How to monitor network performance for each application in FreeBSD / PC-BSD?

I'm using a PC-BSD workstation, and I would like to know if there is a way to monitor which app / process is using the network. I use a Mac OS X (Mavericks) laptop, and the "Network" tab in the ...
2
votes
5answers
8k views

Cannot delete bridge - “bridge br0 is still up; can't delete it”

I have the same problem as this guy : Bring down and delete bridge interface that's up But that solution does not work for me. I remove all interfaces from the bridge using brctl delif . I then ...
0
votes
0answers
61 views

can't connect to remote host with MySQL…firewall problem?

I've granted privileges to thufir for remote access through the shell (correct?), but cannot seem to actually connect. The router firewall has SPI to off. I've disable the IPv6 firewall on the ...
2
votes
2answers
88 views

How to print from a given range of ip addresses every class-c with the last octect replaced by an asterisk

example: I have a range from 10.0.100.0 to 10.0.224.0 and I want the output like this: 10.0.100.* 10.0.101.* 10.0.102.* and so on
1
vote
2answers
1k views

ping: unknown host with iptables enabled

I can't ping www.google.com. However I can ping the IP address: ping 74.125.237.142 At first, I thought it is a problem with my DNS settings. But I checked my resolv.conf, hosts, and hostname ...
0
votes
1answer
32 views

WiFi only connects to my router, not to any other access point

I have a Raspberry Pi 2 with a WiFi USB dongle. I don't know the brand or model, I got it for free with my Xtreamer Mk1 in 2009. My Windows 7 PC installs some generic Realtek RTL8191SU WLAN adapter ...
0
votes
0answers
31 views

eth0/usb0 bridge breaks after removal and replacing android phone

I'd like some help with a networking bridge issue I've run into. I'm trying to make a bridge with eth0 and usb0 (my android phone). After running the brctl commands the bridge works wonderfully. But ...
1
vote
1answer
45 views

Test for open TCP port in bash script

I want to delay the script execution until a certain server process is ready, which it is once it accepts incoming TCP connections. How do I test if a local TCP port is open (I get a SYN/ACK answer)? ...
4
votes
2answers
250 views

Using bash's `/dev/udp`, how would I know if the port was open?

I do not have access to netcat or nmap so I'm trying to use bash and the /dev/udp/ special files to test ports. I could do something like: echo "" > /dev/udp/example.com/8000 But $? is always 0 ...
0
votes
2answers
4k views

Setting up hostapd with a iwlwifi device to run a hotspot

I am trying to configure my opensuse 13.1 system to function as a hotspot (on my dell xps13 computer). So I tried setting up hostapd as explained here, but I get an error: hostapd ...
2
votes
1answer
1k views

Ubuntu: wire network is not stable and must restart network-manager periodcally

I don't know why my wire network now is not stable. After a short time of using, maybe 30 minutes, 15 minutes or maybe just 2 minutes, my network is down. When my network is down, I must run this ...
1
vote
1answer
2k views

How can I disable IPv6 in custom built embedded setup

I have an embedded system built using buildroot. I have had a number of network issues, one of which is that my machine cannot see its gateway despite it being on the same subnet. I have tried using ...
1
vote
0answers
12 views

shared filesystem with offline access

I would like a shared filesystem with offline access. I have two machines. One is a light laptop with a small amount of SSD storage that I carry with me. The other is a stay-at-home computer with much ...
3
votes
1answer
469 views

How do I create a USB networking interface for passing internet to my Android phone?

I am working on passing through the internet from my computer to my phone (running Android) over USB. I'm not sure how to achieve this, but I know I will need a usb network interface, such as usb0. ...
2
votes
1answer
2k views

Understanding ifconfig stats

Please help me understand ifconfig stats, in particular over what time period are they? From the example below the combined receiving bytes for both interfaces is 7.7 GiB. Is that since midnight? ...
3
votes
1answer
627 views

Determine whether XBOX 360 is on

I want to determine in close to real-time (up to 5s lag would be OK) when my XBOX 360 is switched on or off over the network. The XBOX gets a static IP address which I know. However the XBOX seems to ...
2
votes
3answers
4k views

Auto connect to a wireless network (Ångström Linux)

I am using Ångström Linux on BeagleBoard-xM. I have installed a RTL8188SU USB Wi-Fi adapter and configured it properly. But it doesn't connect automatically even though I have marked the interface as ...
5
votes
1answer
1k views

What is SSTP vpn server and how can I run one?

I've read a couple of L2TP and PPTP tutorials on the net and there are just dozens of "running PPTP/L2TP on Linux" guides available out there and I successfully made packages like open-swan or pptpd ...
0
votes
1answer
30 views

How do I limit inbound and outbound bandwidth to and from a specific host on CentOS

As the title says, I am trying to limit inbound and outbound bandwidth to and from a specific host on CentOS. The reason is that this host consistently uses a large amount of bandwidth and this needs ...
0
votes
0answers
34 views

Dropped connections with b43 driver using Broadcom BCM43228 wireless chip on Arch Linux

I managed to get my wireless working with the b43-firmware package in the AUR and for at least a month it worked perfectly. However, recently the internet connection has been dropping out. I'm ...
0
votes
2answers
153 views

Debian autossh boot script not working properly

I wrote the start script at the bottom of this question to try to get one of my devices to automatically create several remote forwarded ports with my VPS upon boot. (I've stripped the LSB tags to ...
1
vote
0answers
12 views

Fair traffic classification using TC

I want to apply a qdisc I developed on myself (quite similar to netem. Think netem.) to several IP-addresses using the filter classifier. No problem this far, I could do so using the prio qdisc or HTB ...
2
votes
1answer
140 views

Understanding why such a discrepancy in network transfer?

Summary: I can't understand a peculiar discrepancy in network transfer. Why is there such a discrepancy in syncing from one machine to the other and vice versa? Also: Given the maximum network ...
1
vote
0answers
103 views

Make docker containers accessible via vpn

I have three physical machine A, B, C, each of them has docker installed. I want to install openvpn server on machine A, and install openvpn client on B and C. B and C will connect to A. I want to ...
0
votes
0answers
28 views

how to set a route and firewall for a static ip

These directions on setting the static ip address for vicidial seem at once very specific and overly broad: Type 'yast lan' and press ENTER Optionally, you can type 'yast' and navigate to the ...
0
votes
1answer
66 views

why can't I ping Google with a static IP address?

I'm trying to install vicibox, an OpenSUSE distro which includes Asterisk. The fine manual says to set a static ip address with yast lan. What's the difference between: ││[ ] Change Hostname via ...
3
votes
2answers
1k views

Open and redirect port

I'm trying to set up SNMP for a router so I can monitor it from an existing Nagios installation on an off-site server. I'm having trouble getting the router to respond to SNMP requests from the WAN, ...
10
votes
6answers
46k 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. ...
0
votes
0answers
18 views

static ip address in yast

I think that I set the FQDN for the server in yast. How do I set the static IP address with yast? I go to network devices => network settings, see my NIC: YaST2 - lan @ arrakis Network Settings ...
0
votes
1answer
18 views

How does tcp communicate back to the application? [closed]

Are there standard sytem calls to send data to TCP? And back? How does TCP tell the application to send more or less?
0
votes
0answers
22 views

how do I set a hostname in yast?

how do I set the hostname, FQDN, in yast? I ran yast => network devices => network services => hostname/DNS: YaST2 - lan @ arrakis Network Settings ...
11
votes
2answers
4k views

How do I tell a script to wait for a process to start accepting requests on a port?

I need a command that will wait for a process to start accepting requests on a specific port. Is there something in linux that does that? while (checkAlive -host localhost -port 13000 == false) ...
0
votes
1answer
34 views

Why can `lsof -i` not show an open connection which `netstat -n` lists?

A strange situation. I started telnet 0 8081 and lsof -i (run under root) doesn't list this connection, but netstat -n does. Why can this be?
3
votes
0answers
39 views

Trickle not behaving as expected

I'm using Ubuntu Trusty 14.04 64 bits. I've installed trickle network shaper from repositories and I performed some tests: No limits I executed this command to test somehow my network download ...