Managing and using network connectivity on a unix system

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103
votes
14answers
327k views

How do I set my DNS when resolv.conf is being overwritten?

Most of the info I see online says to edit /etc/resolv.conf, but any changes I make there just get overridden. $ cat /etc/resolv.conf # Dynamic resolv.conf(5) file for glibc resolver(3) generated by ...
3
votes
2answers
2k views

Getting a list of WiFi networks nearby when the adapter is in AP mode

I am trying to get a list of wireless networks nearby while the adapter is acting as an access point but iwlist returns the following error: $ sudo iwlist wlan0 scan wlan0 Interface doesn't ...
1
vote
2answers
2k views

Huawei E3372s + Linux (Rasbian), Incoming connections problem

I have a Linux-based OS (Rasbian) running on Raspberry Pi 2+ and it is using Huawei E3372s 4G/LTE USB Stick for internet connection. All my outbound connections work perfectly (Huawei USB mode ...
0
votes
0answers
57 views

How do I set up network connection via 3G USB modem for Linux?

I've spent a lot of time searching for a solution, but now I'm here. I need to set up LG 3G USB modem for my Ubuntu 16.04. The system is able to see the device: $ lsusb Bus 001 Device 004: ID 1004:...
0
votes
1answer
2k views

Laptop connected to wifi but no internet

For some reason my wifi has decided to stop working. I can connect to APs, I can have excellent signal strength, but I can't actually load any web pages or ping anything. I know it's my laptop because ...
2
votes
2answers
49 views

Slow scp transfer speed over wan

I have got a 300mbit symmetrical fiberoptic line, and I have got to transfer a 51MBYTE tar file from HOST A (fiberoptic 300mbit) to HOST B (digitalocean machine with more than gigabit bandwith). On ...
1
vote
1answer
975 views

cannot ping my computer on local network

I am running on 64 bit OpenSuSe 13.2 with Gnome 3 desktop environment and unsuccessfully trying to set up Samba Server. I have another computer running windows 8.1 from which I am pinging the ip ...
1
vote
0answers
16 views

If it possible to permanently set a loose source routing option to all ip packages to a specific ip address?

First of all, the loose source routing is a kind of ip options which requires a selected hop to route this package. I wonder if it possible to set loose source routing option on specific ip packages(...
0
votes
0answers
7 views

Why doesn't wpa_supplicant work when using crontab job?

I am writing a script that is installed via a crontab job. The point of the script is to locate a specific AP and connect to it on start up. The script will log its progress to a text file called, "...
1
vote
1answer
21 views

SSH in local network while hosting same network

I have the following setup: Computer A has a Wifi-USB adapter (and is a robot, so it doesn't need real internet access). It's running Ubuntu 14.04. Computer B is my Laptop running Ubuntu 14.04 also. ...
1
vote
1answer
56 views

How would I limit connections to certain services, to be only accesed via a connection coming from a sub-domains?

I have a personall machine running Ubuntu 14.04.4 LTS. I use it to host a Teamspeak and a Minecraft server and also a website. I am trying to make sub-domains to only point to the right services. So ...
1
vote
2answers
28 views

set up NFS two way syncronization [closed]

I have two servers that I want to "share" the home folder of, such that when I make changes on Server A they appear on Server B and when I make changes on Server B they appear on Server A. Right now ...
0
votes
0answers
41 views

Arch-ARM: netctl not working correctly at boot

I've created a netctl profile that assigns a static address and alias to my eth0 NIC, however when I boot the interface doesn't come up at all. I check with systemctl status netctl@eth0.service and ...
0
votes
0answers
14 views

SAMBA Share Not ReadWrite

I've set up a folder (on srv005) /mnt/local/data owned by msc:msc_group. drwxr-xr-x 4 msc msc_group 4096 Jun 9 22:33 data I've set up SAMBA with the following share options: [srv005_data] comment ...
3
votes
0answers
229 views

router latency measured by tcpdump increases

I am using tcpdump to measure latency on a linux router, i.e. the delay experienced by packets as they pass through the router (made of Ubuntu 10). For this purpose, I captured packets in the IN and ...
0
votes
0answers
27 views

My network interface disappears from /run/network/ifstate

Here's the relevant parts of my interfaces configuration file: # grep -vP '^(#|$)' /etc/network/interfaces auto lo iface lo inet loopback auto eth0 iface eth0 inet static address 192.168.0.10/24 ...
1
vote
0answers
52 views

Why is my network unreachable in virtual machine with RHEL 7.2?

I got a 30-Day evaluation of RHEL 7.2. I installed into a VirtualBox machine, and tried to register my subscription: # subscription-manager register Registering to: subscription.rhn.redhat.com:443/...
0
votes
0answers
19 views

What would cause itermittent internet connectivity on my server?

I occasionally have trouble with an ubuntu VM I set up for testing developement work - it occasionally becomes inaccessible to ssh, can't connect to archive.ubuntu.com for updates, etc. It has two ...
0
votes
0answers
14 views

Multiple Subinterfaces on a Wireless NIC (Ubuntu)

I need to create multiple subinterfaces on a wireless NIC. I have done it on a regular wired NIC before but before I test myself, I wanted to find out from the community if it is possible. The ...
2
votes
4answers
15k views

Mounting Directory - Connection Refused

I am trying to mount a Directory from my server to my local machine. This is because I want to edit the directory and execute the files without having the manually push the files to the server after ...
0
votes
0answers
20 views

Changed the DNS Server and cannot connect to Internet from Guest OS!

I recently changed my DNS Server in my router to Google's DNS Server because the ISP's DNS Server was rerouting my every requests to guide.domain-error.com/... when I was trying to connect to Internet ...
0
votes
1answer
46 views

iptables forward all traffic to 2 different interfaces

I'm currently using dnsmasq to create a small Debian box as a DHCP and DNS cache server. Until today, I had just 2 interfaces (eth0, eth1). One connected to my WAN (eth0) and one connected to my LAN (...
2
votes
1answer
28 views

LXC container gets two IP addresses assigned to it

I'm playing around with LXC on my Arch Linux workstation as a learning experience. I'm following the guide on the LXC page on the Archwiki and setting up a static ip for the container. This is what my ...
0
votes
1answer
31 views

How to disable Wake on Lan

Windows also has Wake on Lan that allows a computer to be woken up from sleep; additionally, this can be disabled by a user on said computer. I know that WoL exists on Linux, but how does one ...
0
votes
0answers
19 views

how to install openssl fips on unix

I am new to OpenSSL and trying to install openssl-fips module. Current version is openssl-1.0.1efips. Steps performed --- cd openssl-fips-2.0.12 ./config make sudo make install but it does not ...
2
votes
0answers
47 views

Network traffic monitor “nettop” morphing away from expected results

On Mac, I open a new shell and enter nettop. For a split second I see chrome (as I expected) and some other things going on (had to record screen to catch them); then I'm only shown data on ...
4
votes
2answers
192 views

SSH broken pipe, message authentication code incorrect

I have set up a Ubuntu server that I plan on using to backup my macbook air using rsync. But every time I use rsync, or even scp, the connection drops, with one of the following errors: ...
1
vote
2answers
160 views

can ping google dns, but not google.de -> unknown host // worked in another network

I have a Laptop with debian jessie installed. At my home network, i could connect successfully to the internet (ping google.de successful). At the external network, i can't ping google.de (result: ...
6
votes
4answers
172 views

Did all of the Requests for Comments directly affect the design of Unix networks?

I want to know more about Linux must be one of my most enduring sentiments. But I often find that I learn the most, or perhaps just feel the most satisfied with what I have learned, when I simply ...
0
votes
0answers
24 views

Assign Static IP to KVM CentOS Guest.

I am attempting to set up a CentOS(7) guest on my Linux Mint(17.3) system using KVM. My Mint host has a static IP (10.10.16.247) configured already and is currently fully network functional.I have a ...
0
votes
1answer
37 views

Suricata: nf_queue: full, dropping packets(s)

I am using Suricata IDS in NFQUEUE mode: iptables -A PREROUTING -m mark ! --mark 0x1/0x1 -m comment --comment "Suricata NFQUEUE handler" -j NFQUEUE --queue-num 0 --queue-bypass Today server port ...
3
votes
2answers
1k 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 its dynamic IP address. When this happens, if I check on the status of the dhcpcd service, it says ...
3
votes
1answer
65 views

How to tell whether a process is network I/O intensive or not in user mode in Linux?

I am currently writing a program in Linux which needs to tell whether a specific process is network I/O intensive or not at runtime. I have tried some tools such as iotop and iftop, but none of them ...
0
votes
1answer
38 views

Shorewall 4-interface setup

I am trying to use shorewall on Arch to manage a setup with 2 local networks and 2 ISP connections. Ultimately I want traffic from local network 1 (192.168.1.0/24 interface enp5s0) to use ISP 1 (76. .....
23
votes
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 ...
1
vote
0answers
33 views

cURL: Java website not loading

I can access the configuration page of my device with no problems via web browser (on the GUI). But it doesn't seem to work by using cURL: luis@Fresoncio:~$ curl http://192.168.1.232 <html><...
1
vote
1answer
529 views

routing table “220” in Linux kernel 3.2.0-23-generic

I have a Linux machine with kernel 3.2.0-23-generic and it has rule with priority 220 in RPDB which points to routing table named "220": T42:~# ip rule show 0: from all lookup local 220: ...
0
votes
1answer
2k views

Run root script or command as root in startup application in linux mint

I have a wireless adapter that used to work in Linux mint 16 (dwa 171) after installing drivers for it. Now it won't work the same way anymore since I upgraded to linux mint 17. I've found the only ...
1
vote
0answers
3k views

How to configure mod_rewrite with an Alias in Apache 2.4?

How do I use apache mod_rewrite with an Alias ? I have a test directory that contains the files: correct.html index.html test_httpd.conf wrong.html I would like an example rule using an alias that ...
4
votes
2answers
66 views

Send my IP to remote server every time booting

I want to send my computer's IP automatically every time it boots. I edit /etc/rc.local sleep 10 ifconfig > /tmp/myip scp /tmp/myip <server> exit 0 I tried, and there is no inet addr, ...
0
votes
0answers
15 views

Settings of Poller Interval and Cron Interval on cacti

Latest version running of Cacti on linux machine and I am bit confused with Poller Type, Poller Interval and Cron Interval. The current setup is set to monitor ping latency, linux machine and dns ...
1
vote
1answer
895 views

Allow multicast packages from the bridge to wire in KVM

On a CentOS 6.5 host, I have a couple of guests - Ubuntu 12.04 and CentOS 6.5. The Ubuntu guest is generating mcast traffic that is visible via a tcpdump on the br3 interface. It is also visible on ...
6
votes
2answers
2k views

NAT and source IP filtering in PF, using OpenBSD >= 4.7

I just read a book about PF (The Book Of PF, No Starch), but there's one question not answered by it. If I have a gateway machine using two interfaces, $int_if and $ext_if, and I NAT the packages ...
0
votes
1answer
26 views

internet connection issue after installing ubuntu

I just installed ubuntu 16.04 on a HP labtop. The installation process was finished successfully. I also enabled the wireless internet, the wireless icon shows the wireless connection is established. ...
0
votes
1answer
33 views

Why would a container not be bridged to the local network by default?

From my understanding on container technology (like lxc or docker), when you create a container it by default uses a "private network" like 10.0.1.x. I do not understand why you would not want it on ...
3
votes
1answer
554 views

Create virtual network adapter with own MAC and IP?

I have a server with 4 different IPs over one real NIC. Now i try to setup different virtual network adapter in debian with this IPs. The Problem is, that each IP needs also a specific MAC. Otherwise ...
0
votes
0answers
18 views

Troubleshoot routing in rewrite/virtual host

I don't want a solution as much as a way to find the problem. I am learning networking mostly because it interests me and I set up something in my uncle's restaurant. It looks like this. A soft AP ...
0
votes
0answers
50 views

IP address not seen on ifconfig

I've imported a virtual machine from work onto my home pc and I can't connect to it through SSH. I've checked ifconfig and there is no IP address next to inet. I thought it could be something with ...
1
vote
1answer
29 views

Printing to ubuntu client via network, using php that reside in windows 7 webserver [closed]

I plan to change my windows 7 client to ubuntu 14.04 LTS. The client has a local printer (Epson LX-310) that is used to print an invoice in web app environment built using apache with php (the web ...
3
votes
0answers
42 views

Why “echo f” in the case of clearing conntrack table doesn't work on debian?

Many people don't clear the conntrack table when they want to reload their firewall rules. When you have some ESTABLISHED connections, all the sessions won't be affected when you add a rule that ...