Managing and using network connectivity on a unix system

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Network unreachable

Just did a fresh Arch install but when I ping 8.8.8.8 it says connect : Network is unreachable. I saved iptales rules in /etc/iptables/iptables.conf but they won't load at startup. ip a says that my ...
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2answers
18 views

if a HTTP request is like HTTP://IP/path with a http proxy, will it go to Internet or Ethernet

AWS enterprise VPC http proxy exists Without the HTTP proxy, curl http://169.254.169.254/lastest/meta-data successful, but disconnect to the Internet. This IP address is not Category A, B, C. Use ...
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1answer
15 views

Why do I have more packets than bytes?

I don't know how to explain this. mind blown. ip -s link 2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP mode DEFAULT group default qlen 1000 link/ether RE:DA:...
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4answers
668 views

OpenSSH - map aliases in ~/.ssh/config to IP addresses in command line

Is it possible to query ~/.ssh/config in the command line? Let's say I would like to retrieve what IP address does the particular alias point to in a separate program, is it possible?
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18 views

Automatically to connect to open network with the highest signal strength [on hold]

How can I tell Arch to connect to whatever open Wi-Fi network has the highest signal strength? I want this behaviour with a honeypot partition or user in case my computer is ever stolen.
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3answers
2k views

tcpdump doesn't appear to be capturing any data, why?

I'm trying to capture data with tcpdump like so: $ sudo tcpdump -Xi eth0 I have the device and the PC connected to each other. On both sides I launch a simple test application that sends a message ...
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0answers
24 views

How to determine how much time a process is blocked waiting for networking (socket) activity?

We are having issues with high load (top and uptime) but high CPU idle. Usually, that means high IO wait but that's also low. I believe IO wait typically does not include time a process is blocked ...
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3answers
49 views

Lost in the world of VPN

The Q. If i have a server, is it possible to have that server with a VPN connection, while simultaneously having an entirely separate connection to be able to SSH to from client machine. The Why. I ...
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1answer
74 views

How can I know which IP address of a host is reachable from another?

I don't particularly need a "solution" to something, I'd just like to understand more of the landscape here. So on my CentOS box, I installed a CentOS VM specifically for learning Puppet. When the ...
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2answers
1k views

Wait for a network device to come up before bringing another network device up on boot?

I'm in the middle of setting up my Raspberry Pi running Raspbian as a bridge between my university's wireless network (which requires WPA2-Enterprise authentication) and my private wireless router (...
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0answers
10 views

No connection on Debian with “USB ethernet” (mobile phone sharing 3G)

I just installed debian on my amd64 PC and I need the 'build-essential' pkg to make my wifi drivers...So the only solution I found is plug in my phone and share my data connection. Nevertheless I ...
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2answers
855 views

two NICs in the same subnet— need to set up routing

I have a tricky case: +---+ +----+ |D1 +->eth0---------<-eth0-+D2 | | | | | | +->eth1---------<-eth1-+ | +---+ +--...
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1answer
14 views

Route traffic for a single IP out of eth0, the rest out of wlan0 [duplicate]

I have my laptop connected to an internal network on eth0 and an external network on wlan0. How can I configure my routes to forwarded all traffic for 10.1.1.1 out of eth0, and everything else out of ...
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0answers
16 views

Bridged VirtualBox VM: Is there an internal Host IP address

I'm running a VirtualBox VM in bridged network mode. Is there still an internal IP address for the Host? (I don't want traffic to my host going over the bridged network) To clarify, I do want my VM ...
0
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1answer
14 views

XYMon-Client status not showing in XYMon Server

I have installed XYMon server successfully, but I can't get the client information to show. It took me a while to figure out, but if you add a host to the server that doesn't have the client, it still ...
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0answers
12 views

Detect / log network changes in rasbian/ linux

I just stated using raspberrypi, Trying to learn some networking and linux stuffs. I want to log or detect network changes like If my machine joined a network. If any device joined the network of ...
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0answers
17 views

Apt-get update/update manager downloading slow [on hold]

I am running Linux Mint 18 and my sudo apt-get update/update manager speeds were fine until today. Now they can't even get past 60 kiBs, I have tried changing servers but it was in vain, as all of the ...
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0answers
28 views

Outgoing network connections fail, incoming ssh login delayed [on hold]

I'm having the following trouble with outgoing connections in CentOS: yum cannot connect (just hangs on "Determining fastest mirrors") Could not retrieve mirrorlist http://mirrorlist.centos.org/?...
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1answer
3k 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 ...
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3answers
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 ...
21
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3answers
14k views

Limit outgoing bandwidth on an specific interface

I would like to know the easiest way to limit outgoing bandwidth for an interface. I want to cap the outgoing port speed so that file transfers between my servers don't fail during busy hours. What's ...
0
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1answer
32 views

Network slowness [on hold]

I am facing an issue in my project.We support an App which is hosted on a unix server. Partners try to access the same from many regions. Now some users in an region say "R" are complaining about ...
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1answer
42 views

Is it possible to ping 8.8.8.8 from two interfaces connected to diffrent WANs

I'll start by explaining the situation. I started My project using a raspberry Pi 2 model B and installed Fedora Arm on it. My current Goal is to be able to connect the pi to internet through an ...
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1answer
1k 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 ...
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3answers
43 views

Dnsmasq points nonexistent subdomains point to local IP

There's a specific remote subdomain mymachine.home.com whose the IP changes on all the time that I need to update DNSMasq to have it resolve correctly. But I tested pinging xxxxxx.home.com which ...
0
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1answer
17 views

Why is it taking so long to establish a LAN connection on boot?

I have an issue with a virtual machine taking time to connect to the local network on boot. I create a virtual machine using the following command: virt-install \ --connect qemu:///system \ -...
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1answer
808 views

SSH to Linux Container from Other Machine

I am trying to learn about Linux Containers and this is my first encounter with servers, ssh and many other things that I do not know the terms yet. I create five different containers and authorized ...
1
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1answer
39 views

List *all* IP routes to a destination in the Linux routing table

ip route get 2607:f8b0:4005:804::200e will show me the best (longest prefix) route to google.com, but it does not show all routes that can take me there. Right now I am using ip -6 route show | grep ...
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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 ...
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0answers
21 views

Adding network route for new subnet?

I've found several related questions, but none of them seem to be solving my particular problem. I have a server at 10.a.b.1, and another server at 10.c.d.2. We're in AWS EC2 classic with no control ...
0
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1answer
27 views

Bonding on centos

I have host that running OpenStack. For public access, there bonding (mode active/passive) on nic1 and nic2. Right now both connect at the same switch. Is it possible to connect different switch and ...
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1answer
17 views

Using qdisc prio under htb class

I have 2 services, both operate over the same interface. Service A goal is keep high bandwidth while sending massive amount of data. Service B goal is low latency. Service B packets should always ...
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1answer
810 views

Set persistent static routes for 4 interfaces on 2 CentOS 7.1 servers

I am tasked to set up two test servers running CentOS 7.1 (Minimal install; the NetworkManager is disabled on both), and have run into a set of issues that I would like to get help here. The ...
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2answers
998 views

AP randomly gets unreachable for the clients while hostapd is running

I set up an old PC as a router using Debian Wheezy, hostapd, dhcpd etc. It has 3 NICs and 1 WiFi PCI card (TP-Link L-WN751ND). The problem is that AP randomly gets unreachable for the clients while ...
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2answers
1k 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) ...
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0answers
23 views

ssh: permission denied (publickey) after restoring to a backup that was known to work at the time of backup [duplicate]

So I have a few servers set up behind a bastion. I usually hop from bastion -> server A -> server B using agent forwarding. One day I try to log into server B and for no reason apparent to me I gives ...
0
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1answer
35 views

eth0 interfering with wlan0. pi networking

I've been trying to nail down the WiFi on my pi. In short its frustratingly unreliable when it starts up. I'm want it to be on a static IP and to Currently I have a monitor hooked up to the pi for ...
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2answers
30 views

How can I resolve an IP address to a hostname in Arch Linux? [duplicate]

What is the most concise way to resolve a hostname to a local IP address in Arch Linux?
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3answers
38k views

Linux network troubleshooting and debugging

From time to time Linux and Unix users faced with various network problems. Many of these problems are presented here and at some others troubleshooting forums, but the are very concrete and contains ...
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0answers
41 views

eth0 NO-CARRIER on Arch/Wired Connection Not Working

The device is a DELL Vostro 1510 and I have tried both the r8169 and r8168 kernel modules. ethtool eth0 shows Auto-negotiation: on MDI-X: Unknown and Link Detected: No. Ip link shows <NO-CARRIER,...
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2answers
45 views

What are the rules that determine the default contents of an /etc/hosts file?

What are the rules that decide what goes into the initial /etc/hosts file of a a server with these characteristics? It has a internal IP address for the internal subnet. which is in the 172.20.x.x ...
1
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1answer
36 views

create listening port on IPV6 WITHOUT netcat

I wish to be able to listen to a port (eventually creating a bind shell) on an IPV6 address. I have tried using the netcat installed on the linux (debian) machine I am trying to bind. sadly it seems ...
0
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1answer
11 views

Use network adapter in Kali Linux using vmbox?

I would like to use my network adapter from my laptop in kali linux. I tried changing the network settings inside vmbox but I can't get it to work. I am using oracle virtual machine. Kali linux is ...
0
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1answer
49 views

Redirect all outbound UDP DNS request to a localhost DNS server

I am trying to redirect all outbound DNS request(made from local) to a tunnel running on localhost listen for UDP on 127.0.0.1:5353. iptables -t nat -A OUTPUT -p udp --dport 53 -j DNAT --to 127.0.0.1:...
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5answers
51 views

find IP and PORT in use by Apache

How can I find which IP:PORT Apache web server is monitoring? There are some network commands, but they show the TCP port in use. The machine has multiple network interfaces and the Listen section in ...
2
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1answer
2k views

Static IP address shifting to 192.168.1.251

I have a system with a static IP address of 192.168.1.150. I configured /etc/network/interfaces manually (i.e. without using NetworkManager.) It is a web server hosting three sites. I am having ...
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1answer
20 views

Not getting ip when running dhcpcd wlan0 inside startup script

Rasbian on a Rasberry PI zero. I have disabled the networking and dhcpcd services from startup and want to start networking and get an IP from within my own script, which is initiated from a custom ...
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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 ...
3
votes
1answer
17 views

Display and network card not working if booted without a display

I'm facing a kind of a mysterious problem. We have a PC with Debian 8 installed. It boots fine and works well, unless I try to boot it wihout a display. So, I shutdown the PC, unplug display and then ...
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0answers
21 views

Aircrack-ng not showing any data packets

So I have been having a lot of trouble with aircrack-ng lately, so long story short, I updated my Kali Linux and aircrack-ng to 1.2~rc4, and now there's just a bunch of 0's under #Data when running ...