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Questions tagged [networking]

Managing and using network connectivity on a unix system

0
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1answer
1k views

CentOS 6.7: network is unreachable after a new clean installation

I have a new clean installation of CentOS 6.7, it is not on a VM, but on a dedicated notebook. During the installation procedure I've configured my WiFi connection and have added it on eth0 pre-...
28
votes
5answers
141k views

How to check whether firewall opened for a port but not listening on the port

We will be deploying a new application to a Server and the application will be listening on port 8443. We have asked Network team to open the firewall for the port 8443 on that server before deploying ...
9
votes
2answers
1k 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 ...
0
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0answers
12 views

Two bridges with two WAN interfaces

I want to create two bridges with two upstream WAN interfaces. Virtual Machines connected to the bridges should be able to communicate with each other, but each bridge would have a different WAN ...
0
votes
1answer
24 views

getaddrinfo(), I can specify a service without a host, what does it mean?

man getaddrinfo: int getaddrinfo(const char *node, const char *service, const struct addrinfo *hints, struct addrinfo **res); Either node or service, ...
0
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1answer
2k views

Installing Broadcom Wireless Drivers for Chip BCM4360 on Kali Linux

There are a fair amount of Kali Linux tutorials I have gone over in order to attempt to get the wireless drivers on my 15" retina 2013 macbook pro. None of anything that I have done is working. Any ...
0
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0answers
3 views

Send response based on client request using s6-tcpserver4

I am trying to create a socket where the client receives a response based on their request, but I can not figure out how to achieve this on CentOS 7 using s6-networking from http://skarnet.org/...
0
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1answer
16 views

Permanently clean up network interfaces in CentOS

I have a VM running CentOS which only has one virtual adapter attached. However, if you look at the details you see this: I only want/need the 10.1.x.x address. Where did the others come from? Can ...
3
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0answers
287 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 ...
0
votes
1answer
17 views

When exactly are “dangling” post-up clauses executed?

post-up|down clauses in /etc/network/interfaces on Debian-based distributions can be either defined right after an interface definition, or "dangling". See a very simple example: auto lo iface lo ...
0
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1answer
2k views

linux + how to monitor dropping from ifconfig or ip

How to monitor RX dropped packets in Linux 7 with tcpdump ? Or maybe any other way? And what is RX dropped? ifconfig results on eth1: # ifconfig -a | grep RX | grep dropped RX errors 0 ...
1
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0answers
13 views

Can't connect to network when creating two network namespaces for two NICs

I'm exploring A.B's comment in this question as a workaround to my issue. As a summary, so you don't have to read that whole question: I try to setup two NICs in two separate network namespaces to ...
0
votes
1answer
53 views

Dont know how to display passive devices in network

I have a question about devices in standby-mode on my Wi-Fi network. My configuration consists of a Fritzbox3490 and a Raspberry-PI3. In my Fritzbox connection menu (fritz.box) i can see passive ...
2
votes
0answers
29 views

How can I send duplicate packets, one instantly and one with a delay?

For testing on Linux, I can create duplicate packets where both are sent instantly with the following command: sudo tc qdisc add dev IFACE root netem duplicate 100% How can I create duplicate ...
2
votes
1answer
80 views

How do I to debug a slow network? (ArchBang)

Situation: MacBook Pro (late 2011/i3) with ArchBang has inconsistent network issues (very slow speed, pages fail to load, dns resolution failing). The workaround: systemctl restart NetworkManager....
2
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0answers
45 views

Can I (IGMP) join a stream on two NICs and answer (IGMP) queries on both NICs in Linux?

I made a Linux application to receive multicast traffic. It works when I connect to one interface. When I connect to a stream, in Wireshark, I see an IGMP join, and when the switch sends IGMP queries, ...
0
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0answers
30 views

What is Linux Network Interface?

I am trying to understand Network Namespaces and Netrok Interfaces on Ubuntu 18.04. I created a namespace blue ip netns add blue Then execenter code here sudo ip netns exec blue bash ifconfig ...
2
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1answer
18 views
1
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0answers
10 views

How to control the Bit Rate (mbps) of Raspberry Pi Access Point

I have two "Raspberry Pi 3 B+" boards which are required to be connected. One Raspberry Pi is configured as Access Point (AP) and the other one is just a Client. When both are connected, I write the ...
2
votes
2answers
35 views

Debian workaround 838871: dhcp network configuration without blocking boot process

Is there a workaround for Debian Bug #838871? Problem: I want to have a network configuration on Debian with the following properties: Automatically ifup network interface when a cable is plugged in ...
2
votes
1answer
2k views

How do I assign static IPs for HOST, BRIDGE, and GUEST

I am learning networking by building a small virtual network within a CentOS host. I need some guidance at the highest level to start planning: The Scenario: A CentOS 7 HOST needs to have a ...
2
votes
0answers
15 views

OpenWRT hairpin L2 traffic

I have an OpenWRT Router with embedded switch. I have a KVM machine with macvtap network access. I need guest to host communication. By connecting the host to my Cisco switch hairpin traffic is ...
8
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2answers
11k views

Why is dhclient making DHCP requests on a static interface?

I'm setting up a new Debian system. I have a static IP configured on an interface in /etc/networks/interfaces like so: # The loopback network interface auto lo iface lo inet loopback # The primary ...
24
votes
5answers
35k views

Why does SCP hang on copying files larger than 1405 bytes? [duplicate]

I'm trying to copy a file from one of my local machines to a remote machine. Copying a file with size upto 1405 bytes works fine. When I try to scp a larger file, the file gets copied but the scp ...
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votes
0answers
18 views

Can someone please help me connect to the Internet on Kali Linux? [on hold]

The two networks I have found are labeled 'lo' and 'eth0'. Neither have wireless extensions. I cannot access the Internet on Kali Linux right now. I am not sure what I have to do to do so. I have a ...
0
votes
1answer
1k views

Cannot ping VirtualBox VM using bridged network

I have a Fedora 22 laptop with a VirtualBox VM on it. All worked fine when I attached the VM to my wireless network card, but I want to attach it to my hardwired card because the wireless changes. But ...
40
votes
7answers
161k views

History of IP addresses that accesed a server via ssh

It has come to my attention that a server of mine has been hacked and infected with a known chinese botnet. It was a prototype/testing virtual machine with its own static IP(US address) so no harm ...
0
votes
0answers
342 views

Redsocks transparent proxy to SSH port forward: DNS not working

I am using redsocks to redirect local traffic for the postfix user to a system using SSH dynamic port forwarding. I am trying to use the redsocks dnsu2t module to do this. SSH doesn't support UDP with ...
3
votes
1answer
1k views

Setting multiple IP addresses on private network interface using Vagrant

I am trying to configure IPv4 and IPv6 address on Internal network Vagrant interface but I am unable to do so. Here is the configuration: config.vm.network "private_network", ip: "192.168....
17
votes
7answers
42k views

Is there a way to set network proxy system-wide?

If I want to have GNOME applications (as well as Firefox and Chrome) access the network through a proxy, I need only use gnome-network-properties (a nice and simple GUI I must say). For other apps (e....
0
votes
1answer
26 views

Netcat listens on a wrong port

When I run the command nc -l -p 443 it starts listening but when I try connecting to it it fails. A few hours later I tried with verbose mode nc -lvp 443 and it printed out listening on [any] 2443. ...
1
vote
1answer
3k views

Wi-Fi troubles on Ubuntu 16.04, using Qualcomm Atheros in a Lenovo v510

I have a Lenovo v510, running Ubuntu 16.04, and I can't get wireless networking to work.  'Enable Wi-fi' has no effect, no networks show up.  Some commands that I've tried, and their corresponding ...
0
votes
1answer
24 views

Seeing dead process in nethogs?

nethogs is a very useful tool to see which process(es) send/receive lots of network traffic. But as soon as the process exits, on the next display refresh nethogs no longer displays the process. Is ...
4
votes
4answers
2k views

Is there any way to see how much data I sent via Internet?

A big German ISP (Telekom) recently decided to volume limit their DSL internet connection to 75GB per month. Now I would like to know how much I download / upload. I use Linux Mint 14 Nadia and I ...
0
votes
0answers
39 views

How can I Improve the Performance of My Linux Netfilter module? [closed]

I wrote a very simple netfiter module. In it, I defined 3 hooks: localout and forward to change packets that go out of my PC and prerouting to do the inverse process. localout & forward hooks: ...
0
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0answers
19 views

Creating Iptables rules for router in front of several servers

I'm trying to create a test environment for some software I've written and I'm running into issues with creating the right iptable rules. I have a router that the rules are being written too, and I ...
1
vote
2answers
2k views

Debian Stretch won't resolve hostname, but IP works

I have configured Stretch networking for eth0 (it picked ens3), after setting: GRUB_CMDLINE_LINUX="net.ifnames=0 biosdevname=0" grub-mkconfig -o /boot/grub/grub.cfg reboot so now I have: >: cat /...
0
votes
1answer
650 views

Set SO_TCP_NODELAY (disabling the Nagle Algorithm)

As I know we have a socket option SO_TCP_NODELAY to disable Nagle Algorithm, and I found it is implemented in TCP/IP stack at https://elixir.bootlin.com/linux/v4.4.90/source/net/ipv4/tcp.c#L2401 . ...
10
votes
2answers
4k views

What's the “right way” to effect changes in /etc/resolv.conf with /etc/resolv.conf.d in place?

I the old days, resolv.conf was static and you edited it yourself. Later on, the DHCP client would rewrite it, using some static entries and what it got from the DHCP lease. These days, some ...
0
votes
0answers
26 views

My laptop doesn't detect my wi-fi

Recently my old dell laptop started to work very slowly, so I decided to install linux on it. I choosed debian (cause i like it). everything was ok, i installed drivers, programs etc. but when I tried ...
-1
votes
1answer
40 views

Packet loss on linux but NOT in a vm running on the same machine!

Something seems to be very wrong with my network stack right now. Not sure where to start debugging. I have Ubuntu 18.10 running a windows 10 VM with QEMU/KVM. The network is bridged together so both ...
0
votes
1answer
3k views

Centos 7: No Wifi Adapter found

I have dual booted centos 7 with Windows 10. Once centos 7 setup finished, no wifi connection was available. In the "settings > Wifi", I see a message saying "No wifi adapter found". My wifi adapter ...
1
vote
0answers
41 views

3 IP on one ethernet that not exist!

when i run "ip -d addr" show 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 promiscuity 0 inet 127.0.0.1/8 scope host ...
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votes
0answers
18 views

Debian 10 wifi connection with heavy delay (but no package loss)

$ PING www.debian.org(klecker-misc.debian.org (2001:67c:2564:a119::148:14)) 56 data bytes 64 bytes from klecker-misc.debian.org (2001:67c:2564:a119::148:14): icmp_seq=1 ttl=56 time=19481 ms 64 bytes ...
3
votes
1answer
1k views

Sane can't see Samsung CLX-3305W network scanner in Ubuntu 14.04LTS

I've installed a new Samsung CLX-3305W multifunction printer/scanner a couple of weeks ago on a dual boot system with W7 on one physical drive and Ubuntu 14.04 64-bit on a separate drive. The printer ...
2
votes
1answer
7k views

Network UNCLAIMED - Unable to access internet

My Kubuntu was working well until I think a day ago, and suddenly I don't have access to Wi-Fi. I've tried turning on the connection via the Connection editor but the box was grayed out. After looking ...
0
votes
0answers
11 views

Could I deal with physical network layer via non-root application without writing networkcard driver? [closed]

Could I get fast access to physical network layer using GAS or GCC made program running from shell? Are there possibilities to do it without own drivers creation?
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0answers
15 views

Can't connect to router

I have a problem with my fresh installed Fedora 30. I have internet access via LAN, but I can't ping my router or any website. Also no DNS server like Google's 8.8.8.8. If I look on my profile, my IP ...
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votes
0answers
15 views

Can't access internet connection for arch linux installation [on hold]

My system: I Have 1024 megabytes of RAM, the processor is Intel Pentium(R) Dual-core CPU E5400 @2.70GHz 2.70GHz, manufacturer is biostar and the model is G31D-M7 and now I'm using windows 7 home ...
2
votes
2answers
8k views

Unable to connect to any wifi with NetworkManager due to error: Secrets were required, but not provided

Using NetworkManager on Arch Linux on a MacBookPro14,3, I am unable to connect to any wireless network. I've tried connecting to a number of different WiFi networks (home, mobile hotspot, work) all ...