Stack Exchange Network

Stack Exchange network consists of 175 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.

Visit Stack Exchange

Questions tagged [networking]

Managing and using network connectivity on a unix system

2
votes
1answer
62 views

Why linux allows connection on a different interface ip even if forwarding is disabled?

The system has two interfaces 1.1.1.1 and 1.1.2.1. The sysctl net.ipv4.ip_forward is either disabled or enabled but iptables -P FORWARD DROP is set. Now setting 1.1.1.1 as default route on another 1....
9
votes
7answers
713 views

How can I ping multiple IP addresses at the same time?

I'm aware of the methods where you can run a Bash for loop and ping multiple servers, is there a Linux CLI tool that I can use which will allow for me to do this without having to resort to writing a ...
1
vote
0answers
17 views

Ubuntu not accepting some TCP/IP connections

So I am absolutely losing my marbles here. Ubuntu 18.04.2 I have Docker + Portainer installed via a local container. I can access the portainer UI via https://ip-address:9000 However, I also ...
0
votes
2answers
2k views

Unable to delete “Wired connection 1” using ncmli

Log: NAME UUID TYPE DEVICE Wired connection 1 d1b2ff35-4d72-3bd5-a8e2-d3d9fefce205 802-3-ethernet eth2 admin 6186afb2-7253-...
0
votes
0answers
9 views

Slow download speed with rtl8821ce on Pop!_OS 18.04

I recently bought a HP 15-da0206ng laptop and since my goal was to finally switch from Windows to Linux I installed the Linux distribution Pop!_OS 18.04 LTS which is built on Ubuntu 18.04 LTS. After ...
0
votes
1answer
20 views

Encrypting Wifi Password When Using Wicd

Inspired by this answer, I'm wondering if there is a (relatively) painless way to "hide" the wifi password(s) that is/are present in the /etc/wicd/wireless-settings.conf file. I travel a lot and ...
-2
votes
1answer
19 views

Linux tool to monitor network performance

I need some suggestions about monitoring various network statistics (like RTT, Packet loss, Jitter, packet retransmission) using linux command line. I have tried "SS" command but SS command gives ...
0
votes
0answers
12 views

Issues with NFS/CIFS shares and martian packets when using two interfaces

Background: I have an isolated LAN. The switch is configured with 3 VLANs Here is how my network is setup VLAN Subnet Mask CIDR Range Gateway 10 192.168....
0
votes
1answer
36 views

Policy routing with 2 NICs on the same network seems to not do anything

As noted by dirkt, I'm missing information: This is the continuation of this question, but to summarize, I'm trying to receive a lot of multicast traffic, more than one interface can handle, so in ...
0
votes
1answer
878 views

Understanding network problem (syslog)

I am running a lubuntu 14.04 server and its always worked well, except for the last couple of days it keeps dropping off the LAN. I am using a couple of powerlink adapters to connect it up as WiFi was ...
60
votes
6answers
105k views

Allowing a user to let listen to a port below 1024

I need to allow a user (different from root) to run a server listening on port 80. Is there any way to do this?
1
vote
1answer
49 views

Setting 'DF'-bit in ip-header inside pcap file

There is some .pcap-file with fragmented ip traffic. I replay this file with tcpreplay, but also I need to replay it with DF (don't fragment) bit set in some packets. I supposed that tcprewrite will ...
0
votes
0answers
19 views

Manjaro not connecting to some websites

I have an issue where some network requests return ERR_ADDRESS_UNREACHABLE and others resolve successfully. Success and failure depends on the domain, for example requests to amazon.com resolve while ...
1
vote
1answer
15 views

how to get packets log which are dropped by rp_filter=1

I do need a log of packets which are dropped by rp_filter ... how to do this logging ? which logs how to enable.
0
votes
1answer
1k views

How to set proxy with a config file provided in freebsd

I'm currently trying to update and install packages and other things on a FreeBSD server, but I’m blocked by my proxy. I'm in an university, and there are a few proxies before to go on the internet. ...
0
votes
2answers
54 views

Other machines here in our office can't access my local website within the same network

I'm developing a portal and the main aim for this portal is for all my colleagues (whose machines are connected to the same network) to access the portal. I have tried to reinstall my apache server ...
0
votes
1answer
22 views

How to bind a network namespace to a interface device through a macvlan

I am trying to connect a new network namespace to a netwrok device with the following commands: # create macvlan and associate it to network device in bride mode ip link add macvlan1 link dev1 type ...
1
vote
1answer
43 views

Debian 'mount': same command different errors

I am trying to mount one of network share to my laptop. I am using following command sudo mount -t cifs //server.name/shared /mnt/myfolder -o user="username" However, I am getting very different ...
3
votes
2answers
1k views

How do I route a spare network interface through an SSH tunnel?

I just bought a Raspberry Pi and I am wanting to route an ad hoc wireless network interface fully through an SSH tunnel that was created using another wireless interface. I want to do this so that I ...
1
vote
0answers
17 views

Understanding Networking Issue Ubuntu 18.04

I have a server setup where I've bonded 4 interfaces (bond1) and connected this to a physical switch. I have added this bond1 to an OVS switch ovsbr1 with VM's attached to ovsbr. It seems there was a ...
1
vote
1answer
1k views

FreeBSD: adding ip alias to interface breaks network on primary ip

I am trying to add an alias to my network card (I would like to use jails) on my FreeBSD box. It is running version 10.2-RELEASE-p7 (generic amd64 kernel). The machine is running in a Hyper-V virtual ...
5
votes
1answer
5k views

Using a bridge, an LXC container can't ping router, but the host OS can

I've got a virtual machine running under virtualbox, and in that virtual machine I've got an LXC container I'm trying to bridge to virtualbox's NAT interface: ------------- ----------- -----...
0
votes
1answer
19 views

Limit a VPN server's services to VPN connections only

I have a jump server and I want to put it behind a VPN, I do not want to deploy a separate VPN server and put my jump server behind it. I thought of installing OpenVPN directly onto my jump server and ...
0
votes
1answer
43 views

How can I upgrade a primitive Netcat shell to a fully-featured login shell with tab-completion and line editing?

How can I upgrade a primitive Netcat shell to a fully-featured login shell with tab-completion and line editing? Suppose I start a remote (reverse) shell using Netcat as follows: nc -lvp $port nc $...
0
votes
1answer
20 views

Dig: connection timed out; no servers could be reached. But ping works?

When I try to run the dig command against either my servers IP or nameserver I get an error: root@kali2:/etc# dig q-type=soa @192.168.100.10 ; <<>> DiG 9.11.4-P2-3-Debian <<>&...
22
votes
3answers
65k views

How to permanently disable a network interface?

I've brought down a network interface with ifconfig wlan0 down, but every few hours or so, the wlan0 interface comes back up and I can't figure out why. I don't restart the machine, never changed /...
0
votes
0answers
43 views

How to access data written in a socket without reading it [migrated]

I'm working on an embedded system having Linux. A client thread is writing some data in the socket but what server thread is reading on the other side isn't the same as it was written. Which is ...
3
votes
1answer
25 views

Execute a command when upon receipt of a TCP connection

I would like to run a bash command when a remote connection is successfully established to a specified local open port. I have looked into netcat and socat, but I'm not sure if either have the ...
1
vote
1answer
2k views

CUPS: How to troubleshoot “No printers found” condition?

If I point my browser to http://localhost:631/admin and click on the Find New Printers button, the page that comes up reports No printers found. My (wired, wide-area) internet connection works fine (...
1
vote
0answers
18 views

PXE Boot: “Failed to load ldlinux.c32”

I'm trying to create a PXE server on my raspberry pi, but if I try to boot, the client shows the Error "Failed to load ldlinux.c32". This is my folder structure of the tftp folder: Here is my ...
8
votes
2answers
1k views

Trying to understand Auto reconnect WIFI method

I found this method of reconnecting the WIFI dongle from this post. But, I want to be clear on how it works, before I try and implement it. Go to /etc/ifplugd/action.d/ and rename the ifupdown ...
1
vote
1answer
204 views

Timeout when mounting EFS on EC2

Let us say I have an EC2 VM which we will call V in security group S1. I have an EFS mount point which we will call M in security group S2. Everything is in the same VPC, on the same subnet, in the ...
1
vote
1answer
34 views

NTP - localhost timeout - source network uses eth0 instead of lo

ntpq -p commands are timing out for me in a centos 6 server. # ntpq -pn 127.0.0.1: timed out, nothing received ***Request timed out tcpdump result shows me that it is using eth0 instead of loopback ...
1
vote
1answer
23 views

How to connect a namespace to a physical interface through a bridge and veth pair

My attempt is modeled on the this tutorial. I am able to ping from the namespace to the network if the physical interface is not assigned to the bridge. # Create namespace ip netns add namespace1 #...
0
votes
1answer
10 views

How do I check if my VM is using vhost-net driver for networking

In KVM, NIC model can be set to virtio (latest) or the older e1000 (not recommended, emulated). In virtio, one has the option of using vhost-net driver or qemu. vhost-net and qemu differs in how ...
0
votes
0answers
25 views

Ethernet interface not working on embedded QNX device

I have A device running QNX which I can connect to over WiFi through a netgear router but which doesn't connect over ethernet. I'm pretty sure it has to do with the netmask which is in a format I ...
0
votes
1answer
44 views

What order is “/proc/net/tcp” being displayed

When you view the /proc/net/tcp or the /proc/net/tcp6 files you are able to see the open ports on the machine itself. But just wondering in what order are these entries being listed in?
10
votes
7answers
21k views

rsync keeps disconnecting: broken pipe

I'm using rsync to backup my home directory. This has been working fine for a long time now. Here's the command I'm using: rsync \ -pavz \ --delete \ --exclude 'mnt/' \ --exclude '....
1
vote
1answer
51 views

Accessing Windows 10 public share from Ubuntu without username or password

I have a Windows 10 PC with a public share set up, and want to be able to access files on the share without providing a username and password to connect. Other Windows PCs can access it using ⁠//...
0
votes
0answers
21 views

Network is down, reopening socket

I cannot bring up my eth0, I tried to call udhcpc to get IP, but it showed as "Network is down, reopening socket" and "ifconfig: SIOCSIFFLAGS: Cannot assign requested address" Can someone please help? ...
1
vote
1answer
1k views

Why is my UDP bandwidth significantly lower than TCP bandwidth in iperf

I am running a simple bandwidth test between two VMs using iperf. I am getting very different bandwidth reading for TCP and UDP where the UDP bandwidth is terribly lower than TCP. TCP: root@i-sahmed-...
1
vote
0answers
66 views

Disconnecting unwanted remote access

If someone is remotely connected to my single ARM board computer with Debian 32-bit OS, (example: thru hijacking the browser), which connects through a firewall on a separate Orange Pi board, and I ...
0
votes
0answers
17 views

Can I turn kernel params to make the network stack using swap instead of physical memory?

I'm doing a test about high-currency, and I only have a machine with limited memory. My goal is to setup more than 10M TCP connections on this memory limited machine. It seems that the network stack ...
1
vote
1answer
1k views

How do you create an ip alias using iproute utils?

While reading the O'Reilley book on Apache Web Server, they gave an example on using ifconfig to set ip aliases on an interface: ifconfig ep0 192.168.123.2 ifconfig ep0 192.168.123.3 alias netmask ...
1
vote
0answers
14 views

How to chain two proxies, or: How to redirect network traffic from one process, to a local proxy

Here's the scenario: I have a proxy, that when Chrome is setup to map requests to, records the requests from Chrome + the responses from the real server. It records all of this in a special format, so ...
5
votes
1answer
1k views

Linux Mint 18 can't connect to PEAP-MSCHAPv2 encrypted school wifi

Freshly installed Linux mint 18, Cinnamon desktop. My computer is Dell Vostro 5460, and the wireless card is intel wireless-N 2230. I can connect to WPA/WPA2 home wifi and the wireless network ...
7
votes
2answers
1k views

How can I monitor the length of the accept queue?

I have a hypothesis: sometimes TCP connections arrive faster than my server can accept() them. They queue up until the queue overflows and then there are problems. How can I confirm this is happening?...
4
votes
2answers
2k views

Issues with connecting to open WiFi network via /etc/network/interfaces

I've previously been able to connect to an open WiFi network on a BeagleBone with a WiFi dongle by adding the following to /etc/network/interfaces: auto wlan0 allow-hotplug wlan0 # For automatic ...
-1
votes
0answers
26 views

Unable to get wifi adapter to work/install on arch linux [closed]

I have tried installing this driver in arch linux (rtl8821AU - https://aur.archlinux.org/packages/rtl88xxau-aircrack-dkms-git) that is in AUR and still no go. They (Wise-Tiger) have stand alone ...
1
vote
1answer
1k views

iptables: route packets to example.com via public proxy

I want to access certain websites via a public proxy and I can't seem to get it right using iptables. Let's say I want to access example.com having ip address 1.2.3.4 via a public proxy at 5.6.7.8:...