Managing and using network connectivity on a unix system

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2
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0answers
6k views

Ping command results in packet loss

Whenever I ping on my personal computer, nothing gets displayed other than a single statement. Upon stopping execution, I see that several packets were transmitted in the statistics. On top of all ...
2
votes
0answers
65 views

ftp failing to retrieve directory listing

I'm trying to connect to my ftp server but I'm getting Status: Disconnected from server Status: Connecting to 127.0.0.1:21... Status: Connection established, waiting for welcome message... Status: ...
1
vote
1answer
20 views

Very low disk performance on Samba

I'm using Samba on Debian 8.4 (Jessie) to share files with a small number of Windows & Mac users (~20 total, ~5 at a time at most) and I'm seeing abysmal performance on read and write: tested by ...
38
votes
8answers
13k views

Block network access of a process?

Is it possible to block the (outgoing) network access of a single process?
0
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0answers
23 views

Can Linux decapsulate double GRE encapsulation?

For an application when the packets arrive at the receiving host, those packets are double GRE encapsulated (IP Hdr + GRE Hdr + IP Hdr + GRE Hdr + payload packet). I am wondering if Linux kernel in ...
1
vote
1answer
3k views

Trouble switching from DHCP to a static IP on Kali Linux

When I installed Kali Linux 64bit, I forgot to set up a static IP address, and now DHCP determines my address with my router. I have already modified /etc/hosts and /etc/network/interfaces to declare ...
0
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2answers
235 views

How to route 3 computers in a wireless ad-hoc network?

I have 3 computers: 192.168.2.1, 192.168.2.2, 192.168.2.4 connected into an wireless ad-hoc network. I want all the traffic from 192.168.2.1 to go through 192.168.2.2 when it talks to 192.168.2.3. ...
5
votes
1answer
5k views

Understand the Route table

I just setup the OpenVPN and it is working as expected. However, the routing table of the client is confusing me to no end. Here is the route table: # route -n Kernel IP routing table Destination ...
2
votes
2answers
1k views

I can ping internal to outside but not from outside to internal (Static IP)?

I have a static IP provided by the administrator of my Linux CentOS 6.5. The problem is that while I can ping this machine, connect to it and use it to access the internet from within my network, I ...
0
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0answers
26 views

Why is a 'Trusted Network' Port More Secure?

I'm working through this tutorial ATM. http://www.cyberciti.biz/tips/using-nginx-as-reverse-proxy.html I'm planning on using NGINX for a simpler scenario but I'm curious as to why the tutorial ...
3
votes
1answer
45 views

Add route from internal network to external network

I am using a box running Arch as my router and firewall (with shorewall). Recently, I tried to add another network onto the system, which failed horribly. After putting everything back where it was ...
1
vote
2answers
69 views

How to Do Split Tunnelling with Slave ppp0 VPN + 2nd VPN?

Network Finland(internet)-PC(Sweden)-Uni(Sweden). Uni IP is fixed. Finland(internet) is gained with 3g-4 connection. I need to use a VPN provider to change my country but the VPN provider gives ppp0, ...
5
votes
1answer
91 views

How do I figure out where wrong local dns results are coming from?

I'm running mint Mate 17.2. When I use dig, for a certain specific domain name, the resolved IP "answer" is wrong, and the answer server is 127.0.0.1. Trying to access this domain from my local ...
1
vote
2answers
977 views

No Default Gateway route for bond0 / Slave eth* interface gets IP assigned

I have set up a 4-NIC bond on my Debian Wheezy box. After a fresh boot, the system has LAN access, but cannot resolve outside host names or access outside IPs. It seems that this is because the bond0 ...
5
votes
4answers
5k 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 ...
1
vote
2answers
42 views

Renew my ip address (dhclient not found) [closed]

I recently got a new cable modem and my internet connection is no longer working. I suspect I need to renew my IP address. How can I renew my address? The command ifconfig returns: bash: ifconfig: ...
1
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0answers
26 views

WiFi Drivers Not Working

I just installed Linux Mint 17.3 on my mid 2012 MacBook Pro. I'm currently trying to install the necessary drivers for WiFi via Driver Manager (nvidia-331 and bcmwl-kernel-source) for my BCM4222 ...
1
vote
1answer
55 views

WPA_CLI showing access point as connected when it shouldn't

I'm using linux kernel 3.3 and am trying to use the wpa_cli utility to monitor the status of my WiFi connection. I'm using an Edimax WiFi dongle to connect to a wireless access point. Normally I see ...
0
votes
1answer
338 views

Apache server in raspberry PI not visible from outside( public IP)

I have made a fresh install of Arch Linux ARM into a Raspberry PI and I mounted there a LAMP, all fresh. I have another Arch(x86) in my laptop with Apache also there, and as far as I know, two web ...
2
votes
0answers
41 views

DHCP to assign different addresses for multiple interfaces and subnets

First of all, I'd like to point out that I've read any related questions asked here. So, on my desktop computer (running Ubuntu) I have three NICs - eth0, eth2, eth3. I have links connecting these ...
1
vote
0answers
19 views

NAO robot running Gentoo based OS cannot connect to Wi-Fi automatically

I am using NAO robot for my Masters Thesis. It is running OpenNAO OS Version 2.1.4.13. This OS is Gentoo based. The problem I am facing is that it doesn't automatically connect to one specific Wi-Fi ...
2
votes
0answers
20 views

SNR or signal and noise levels in ad-hoc mode

I am using the WiPi dongle which is based on the rt2800usb driver on my Raspberry Pis (running raspbian) in an ad-hoc network, and I can't seem to be able to get any SNR, signal or noise level ...
1
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2answers
879 views

What's the best way to have a 169.254.169.254 address local to my laptop?

I want to emulate the Amazon EC2 metadata service on my local system for testing. In EC2, this runs on 169.254.169.254. I understand that this is the designated range for pseudorandom local addresses ...
12
votes
5answers
11k views

Simple way to create a tunnel from one local port to another?

I have a development server, which is only accessible from 127.0.0.1:8000, not 192.168.1.x:8000. As a quick hack, is there a way to set up something to listen on another port (say, 8001) so that from ...
1
vote
1answer
35 views

TCP over TUN: SYN/ACK is received, but no ACK is generated, and socket remains in SYN_SENT state

I am tunneling an outgoing TCP connection over a TUN interface set up by a program I wrote. The TUN interface basically just relays the packets to/from a proxy server, with minimal modifications (...
0
votes
1answer
36 views

How to disable interface just for NetworkManager in Kali Linux?

I have two WLAN interfaces, and I want to disable one of them for NetworkManager, so that if I run something like service network-manager stop, all the interfaces should stop except on of the WLAN ...
0
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0answers
28 views

Virtualbox connectity from vboxnet0 to internal network

I am trying to create a setup with gateway(Guest OS Ubuntu) in middle and an webserver(Guest OS - Debian) - must be connected to VM-2 only via VM-1 from host pc. My aim is to ping 10.1.1.2 from Host ...
0
votes
4answers
59 views

Setting up hostnames on local network [duplicate]

So, I'm setting up an experiment network for me and the other geeks at my school to use for website testing and server practice, and I'm the sys and net admin (but really it's just for playing Quake). ...
0
votes
1answer
3k views

Consistent network interface name ubuntu using pci slot

One can set consistent interface naming via mac address by modifying /etc/udev/rules.d/70-persistent-net.rules. Can you establish consistent interface naming by PCI slot number? (I tried but failed) ...
2
votes
1answer
57 views

Network interface crashes after disconnecting eth wire or restarting service

At startup or reboot, network interface works fine. Host is reachable and also can communicate with other devices on the local net or internet. IP address is configured as static, and dns-nameservers ...
0
votes
0answers
153 views

KVM network packet loss to guest

I am running a server with Debian 8.3, uname output Linux x 3.16.0-4-amd64 #1 SMP Debian 3.16.7-ckt20-1+deb8u3 (2016-01-17) x86_64 GNU/Linux I am using KVM to run a virtual machine with CentOS 7.2....
15
votes
5answers
15k 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 that I can recover my hung sessions after I reconnect? EDIT: am doing some updating and installing with ...
3
votes
2answers
46 views

Timeout with 'service network restart'

I have a script running on fedora 22 where I am restarting service network as part of a troubleshoot calling service network restart. I want to check if that command is taking too long to execute. If ...
1
vote
0answers
63 views

How to do iptables nat loopback?

I have a linux server behind the ISP's cablemodem-router combo. With some hacking I was able to make the port forwarding work, and the DHCP exceptions in the udhcpd. But I wasn't able to do the NAT ...
0
votes
1answer
5k views

Linux Mint 17, Wifi Slow and Drops Connection, No Ethernet Connection

On a fresh install and updated Linux Mint 17 XFCE, the system cannot maintain an internet connection through wifi, and is unable to connect at all through ethernet. Wifi will work somewhat slowly for ...
1
vote
1answer
37 views

Is there a way to send packets through one ISP and receive answers through another one?

I just finished building my first load balancer that combines two different ISPs. This mechanism works just fine, but it's a little bit limited because a connection can't simply utilize both ISP at ...
1
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0answers
18 views

Networking failed to start on Alpine linux

I keep having an error when booting Alpine Linux Networking failed to start. I'm using a RPI3 which is connected by an ethernet cable to the box. Here's the /etc/network/interfaces : auto lo iface lo ...
1
vote
2answers
3k views

Why can't nmtui see wlp3s0 on minimal CentOS 7 installation?

In a recent installation of a minimal version of CentOS 7 (terminal only, no GUI), typing iwconfig results in the terminal showing a wlp3s0 connection, as follows: [root@localhost ...
3
votes
1answer
15k views

How do I configure the network interfaces persistently in CentOS so it will survive a reboot?

I configured a network interface with the following commands: ifconfig eth0 up ip addr add 192.168.9.1/28 dev eth0 route add default gw 192.168.0.1 This works. However, when I reboot the machine I ...
2
votes
1answer
1k views

RHEL how to sync network settings between GUI and configuration files in /etc/sysconfig/network-scripts/?

In RHEL, we can change network settings either using GUI or editing the configuration files in /etc/sysconfig/network-scripts/. I would like to know how the network settings (e.g. IP address, gateway,...
2
votes
1answer
573 views

How would I go about getting UPnP working on a Slackware server/firewall?

I'm a long time fan of Slackware and I've always had a machine serving as my main server/firewall with the latest version installed. I have it now but I'm struggling to find information on how to ...
0
votes
2answers
33 views

Linux bridging question

I'm trying to understand why many Linux (virtual) networking guides attach IP addresses to a bridge device? A physical bridge itself doesn't really have an IP, instead one attaches networks to it and ...
1
vote
1answer
871 views

How does KVM set its own netfilter rules?

I've been poking around with KVM VM's on Centos 6.4 not having an internet connection on my VM's, I found something curious: Upon booting the machine, iptables has rules in the FORWARD chain to allow ...
1
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0answers
30 views

AIX: network and route problem [closed]

I changed my router some days ago. ping, internet, and network are working on AIX, but SSH is terribly slow. For connecting to other hosts on the same network it takes... two minutes! This is my ...
0
votes
1answer
15 views

Where does a Centos7 VM get the IP address for the local host name from?

On my centos7 VM, hostname says bmargulies-centos7, domainname says (none), dig bmargulies-centos7 says what's below, and ping of that hostname hangs. Where does the IP address 92.242.140.21 come from?...
1
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1answer
15 views

linux - context-based access control

I would like to further restrict network traffic based on the source / destination application. To do that, I'm using network namespaces, but is there a better / simpler approach? My approach ...
1
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3answers
43 views

Check my DHCP lease?

Is there a way to show my current (client) DHCP lease? Or even better - retrieve all options/infos sent with DHCPACK?
1
vote
2answers
42 views

How to execute a command when internet is back

Sometimes my wifi is connected to router but my router is not connected to internet. How can I execute a command when my internet is back (from command line)? I want to execute: mpg123 /home/user/...
1
vote
0answers
35 views

How to have systemd-resolved correctly come alive after hot plug?

Setup I am playing with a small embedded board running Debian Jessie. I am using as much systemd stuff as I can, including the networking stuff. I have added the file: /etc/systemd/network/eth0-dhcp....
0
votes
1answer
28 views

hostname -f .com.com

I modified my /etc/hostname file and /etc/hosts like that: hostname.com and 127.0.0.1 localhost.localdomain localhost ::1 localhost ip6-localhost ip6-loopback ff02::1 ...