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Questions tagged [networking]

Managing and using network connectivity on a unix system

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10 views

Wi-Fi not working on Debian 9

I have a Debian 9 Stretch OS running.  Last night when I shut it down the Wi-Fi was working perfectly.  Today I turned my laptop on and it's not showing any Wi-Fi, and I cannot enable Wi-Fi.  Here is ...
0
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0answers
6 views

Unable to connect to internet after enabling wake on lan on Debian 9

I've enabled Wake-On-Lan on my debian machine with this tutorial. I didn't have the option to try it out or reboot, and went to sleep. The next day, a power surge happened, and rebooted my computer, ...
0
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1answer
31 views

CentOS loses internet connection

I have configured CentOS VM, with NetworkManager disabled. Question: When I start VM I have access to the internet, but after a while I lose it. How can I fix that?
0
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1answer
23 views

Logrotate is not compressing

I need to compress the files in var/log/remots/*/* with the following logrotate rule /var/log/remots/*/* { rotate 178 daily maxage 178 compress } located in /etc/logrotate.d/remots. ...
0
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1answer
23 views

Security issues about running VirtualBox with bridged-adapter

I set up a Gnu/Linux VirtualBox, and I configured networking to support both NAT and bridged connections, in order to ssh to it remotely from a different PC in my network. Since an IP was assigned to ...
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0answers
14 views

Reroute URL pointing to single file

Given I don't like i.e. a favicon and want my system to have i.e. https://kai.dj/favicon.ico pointing to https://git.kai.dj/favicon.ico instead. Of cource I wouldn't like to reroute the whole domain (...
0
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0answers
16 views

Netstat operation [on hold]

I would like to have a deep sight about how netstat works ina low level. I mean, if I use netstat to see open ports, how netstat checks them (checking running processes or with some system functions ...
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0answers
10 views

Can not ping network switch Fedora 29

Setup I have a dual boot fedora 29 & windows 10 setup. The system is connected to a network switch via an ethernet cable. The network switch is configured to serve a management web-ui on the ...
0
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1answer
18 views

Can i configure the browser to use one network interface and other apps to use the second?

I have a Linux box (Debian 9) with 2 NICs (Ethernet & Wifi) and they both connect to different networks. Is it possible to configure the browser to use the Wifi NIC and all the rest of apps to use ...
0
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2answers
61 views

When does `[::]` or `0.0.0.0` mean this network and when this host? [duplicate]

Tanenbaum's Computer Networks says The IP address 0.0.0.0, the lowest address, is used by hosts when they are being booted. It means ‘‘this network’’ or ‘‘this host.’’ [::] is IPv6 version of ...
0
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1answer
13 views

Dnsmasq/Ubuntu “NoDHCP or proxyDHCP offers were received”

I've spun up a Ubuntu 18.04 (Bionic Beaver) server* with the intention of mounting the DBAN .iso so that I can PXE boot this. *server version of Ubuntu but this is actually desktop hardware (a Dell ...
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2answers
93 views

Are the IPv4 and IPv6 networks for my loopback interface the same network?

In output of ifconfig: lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536 inet 127.0.0.1 netmask 255.0.0.0 inet6 ::1 prefixlen 128 scopeid 0x10<host> loop txqueuelen ...
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0answers
26 views

How to receive data from a Webpage and send it back to it in the same connection?

I am trying to fill a form of a webpage with curl and give it some arguments. Dumb enough, it also sends a hidden form in which there is an unique token which has to be sent back to the page, a so ...
0
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0answers
17 views

Packet traversal in the Linux networking stack

I am trying to understand the packet traversal in Linux. I found a diagram from link. My linux box has the following routing table: default via 192.168.2.1 dev wlan0 proto static metric 1024 169....
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0answers
4 views

Getting Count of Packets Waiting in Kernel (or NIC) for Process

Is there any way for a process to ask the kernel how many network packets are waiting for it to handle? (I’m not sure whether those packets queue in the kernel or the NIC). I’m running Clear Linux.
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0answers
42 views

How do I return packets to the same MAC address they came from?

Let me start with a diagram: Workstation -> TrafficShaper -> Internet | ^ V | LinuxProxy --------- My traffic ...
1
vote
2answers
47 views

Traffic between subnets VirtualBox

I'm trying to build a prototype of a real network in VirtualBox. I have 3 guest systems: Debian-based router with 3 NICs: enp0s3 Looks outsude.(bridged) enp0s8 LAN1.(gateway to internal ...
1
vote
1answer
34 views

How to dump traffic without the usual tools like tcpdump?

I have a router which runs the Broadcom aeolus system: https://github.com/Broadcom/aeolus consisting of ecos and "normal" Linux. I want to dump all the WAN traffic (controlled by ecos I think) or at ...
0
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0answers
14 views

Swap Primary and Secondary IP addresses on Raspbian 9.8

I'm trying to flip flop the IP addresses on eth0 and eth0:1 with as little downtime as possible. So far I have tried changing the IP addresses in /etc/network/interfaces, then running ifdown eth0:1 &...
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0answers
26 views

Routing outgoing traffic between two NIC

I'm looking for a solution to proxify all the outgoing connections through several network interfaces so that they would appear to come from different IP's and I'm using Ubuntu 18.04 EC2's. What I ...
2
votes
1answer
24 views

Have to restart network service after reboot (centos 7)

I am setting up a server which has a 4 ports (em1 to em4) QLogic network interface. It is connected though em3 and the IP address is automatically given by DHCP based on the mac address. I do not ...
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0answers
23 views

Installing Broadcom wi-fi driver in Debian without internet connection [on hold]

I have a MacBook and I need to install the wi-fi driver. However I don't have access to the internet from Debian. What should I do? I have downloaded all the firmware .deb packages from non-official ...
2
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2answers
69 views

why MTU change from 1500 to 9000

in /var/log/message file we found something interesting Mar 9 07:08:32 linux54 kernel: ixgbe 0000:0b:00.1 en3j87: changing MTU from 1500 to 9000 we can see the interface card - en3j87 change from ...
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0answers
22 views

services on host no longer reacheable from outside, after adding bridge

before adding the bridge, different http services were reachable from other hosts. After adding the bridge, only ssh is reachable from other hosts. All other services are only reachable from the host ...
0
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1answer
13 views

Adding a loopback interface

I would like to "overwrite" IP addresses that already exists on the public internet. So, I want to create multiple loopback interfaces on a machine, so I can ping any IP address that I configure from ...
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0answers
75 views

Is VPN a layer 3 or 5 concept? [closed]

From Tanenbaum's Computer Network This demand soon led to the invention of VPNs (Virtual Private Networks), which are overlay networks on top of public networks but with most of the properties of ...
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0answers
14 views

Capture and replay network traffic of a specific executable

Is there a tool that allows me to capture and replay network traffic of a specific executable? tcpdump/tcpreplay need root permissions (which I would like to avoid if possible) and are not aware which ...
0
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0answers
14 views

Dell poweredge running ubuntu server, redundant interfaces

I have an ubuntu server 18.04 with redundant internet interfaces. As of now my ifconfig looks like this: eno1: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500 inet 192.168.0.150 ...
0
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0answers
35 views

Bind SSH client to two different host addresses

I have this port forwarding solution for testing purposes. There is a distant server named box and a local machine named tower, on two separate networks. box is accessible through the internet. On ...
0
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1answer
27 views

How can I configure bidirectional protocol-independent port forwarding?

I am attempting to solve the following problem: I have a system which I will henceforth refer to as "Local" that hosts a service on port 80 and port 443, and depends on sending outgoing requests on ...
0
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0answers
19 views

How to add a default route to a DHCP-enabled interface?

All my servers' networking is configured via DHCP which sends, among others, a static route (needed for a VPN) and a gateway. This works fine. I have one exception: a server which should not get the ...
0
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2answers
53 views

Is there any way to know how many sockets have been created by a C program?

I have been running a C program which connects to a Redis database every once in a while. After running the program for a few hours it was displaying "Cannot create socket: too many files open". I'm ...
0
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1answer
21 views

How to set a static IP using netplan? (running Ubuntu Bionic server)

My problem is that no static IP is getting assigned to the built-in ethernet port. I have run netplan apply several times. I've also rebooted the PC and still no luck. I am sure the ethernet port ...
0
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0answers
43 views

How to allow SSH over PPP?

I have these two computers connected through ppp. One has ip 10.10.0.1 and the other has ip 10.10.0.2. Both also have the interface ppp0 with netmask 255.255.255.255: # ifconfig ppp0: flags=4305<...
0
votes
1answer
28 views

Can I test telnet connectivity FROM multiple machines TO multiple machines, via a script?

I have 10 source machines and 10 destination machines. Each of those source machines need to connect to each of those destination machines. I wrote a shell script which tests the telnet connectivity ...
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0answers
14 views

Link specific connections (ADSL or 4G LTE) to different software

I have access to two Internet connections from two different plans: ADSL and 4G LTE. In Xubuntu, I can chose a specific connection using the network manager applet, but then the one that is chosen is ...
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0answers
25 views

how to turn off tcp timestamps?

I tried to turn off the tcp timestamp but it didn't work. The step i performed are the following: $ sysctl -w net.ipv4.tcp_timestamps=0 $ sysctl -p $ sysctl net.ipv4.tcp_timestamps (=> to be sure ...
2
votes
1answer
35 views

Use different connections (wifi + ethernet) to increase speed on lan

I have a laptop with a 100mb/s ethernet and a 75mb/s wireless connection to my internet router. This is the maximum speed each network adapter can get in my laptop, but my external link is higher. I'...
0
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0answers
27 views

Ethernet network disconnected but the cable is actually plugged in

I have recently installed GalliumOS alpha on my Acer Chromebook 14. WiFi works flawlessly, but I can't get the Ethernet connection to work as network manager says "disconnected" under Ethernet Network....
0
votes
1answer
23 views

Curl giving different responses on connection timeout

I use Ubuntu 18.04 and I try to curl the unavailable resource like: curl 192.168.11.1 --connect-timeout 10 curl 192.168.11.1 --connect-timeout 35 Why does it sometimes respond with curl: (7) Failed ...
2
votes
1answer
40 views

How to install packages with no internet on Fedora 29?

I have a CHUWI Lapbook 15 which I want to install Fedora on. I will often start installation of Fedora with the server spin as it is minimal and doesn't need to first boot into a live cd. The problem ...
0
votes
1answer
17 views

Multiple Remote KVM Computers

I want to ask if it is possible to have multiple (3-6) Windows Virtual machines on a Unix Server system. The Windows VMs should communicate with each other over the network and every VM should be ...
1
vote
0answers
29 views

TCP/IP quits after 48 hours

I have a problem with a (remote) server running SCO UNIX. It's been working for years, but was recently moved, and I changed its IP address & gateway address. Since then it works perfectly until ...
3
votes
2answers
159 views

Has the filtering of all kinds of TCP attacks using iptables become obsolete as they get filtered elsewhere or something else?

Background I am on Debian 10 Buster. I started running a Tor relay on my home IP address. A dedicated full-fledged server is probably not the most energy efficient way, but I want to try it out. And ...
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1answer
34 views

grep routing table & execute command

I'm trying to make a script on my Linux machine that will grep for a specific routing in my routing table and execute command depends on the find. This is what I have so far and it's not working: #!/...
0
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0answers
39 views

How do you find the static (and dynamic) information about the network currently connected to?

Is there some command (on Linux) which report the static (and dynamic) information about the network currently connected to? For example, BSSD, encryption method (WPA, or ...), and more. In particular ...
0
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1answer
32 views

Network Bridge for VM not working after reboot

I have a CentOS 7 host with a network bridge set up for guest VM's to use. All was well until a recent reboot. After the reboot, the guest VM does not have internet access, nor can it ping other local ...
0
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0answers
12 views

Can’t connect to network Pop-OS 18.04

After using my Linux install for a while, I woke up this morning not being able to connect to the internet via WiFi. I found that I have no routes showing up when running the ip route command. I tried ...
10
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2answers
874 views

Why does cron require MTA for logging?

Why does cron require MTA for logging? Is there any particular advantage to this? Why can't it create a log file like most other utilities?
0
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1answer
12 views

KVM: how do I add host route when VM starts?

Is there a way to automatically add a host route (pointing to the VM IP) when VM starts ? ATM I'm doing this by hand. I've also tried to add a route via /etc/sysconfig/network-scripts/route-virbr0 ...