Newest networking Questions

Q&A for system and network administrators

How do I connect a docker container to multiple ips on the same macvlan network?

When I attempt to add a second ip address to my docker container in the same macvlan network, using the create, docker network connect, start pattern it appears to override the first ip address. ...

PHP throwing server errors after Ubuntu ran an unattended-upgrades session - any way to determine the cause?

We just had an incident on one of our webservers. Several PHP applications run on it and started spitting out the following error message: php_network_getaddresses: getaddrinfo failed: Name or ...

Can't open port on Amazon EC2 instance

I have an API which I successfully hosted on Amazon AMI instance. I know that's for sure because I can use it locally using curl. Api hosted on port 8080. That's what I putted into cmd for open port: ...

Squirrels ate my wires (cover forest with WiFi) [on hold]

I need to cover such area (100m 1-floor building and 1000m dense wooded park) with stable WiFi connection. We have ~20 employees moving around this area and uploading ~20 files of a 5-10MB every ...

Are IPs assinged by APIPA static?

I have two virtual machines that are on the same network via VirtualBox. There is no DHCP server and their IPs are assinged by the APIPA automatically. I'm wondering are those IP static, in a way that ...

Wireless clients getting ips my router is not assigning

I'm running a small network with a peplink router and unifi access points. The wireless network is a vlan than has no access to the main network. For some reason that I can not figure out, some ...

1st Ansible Program - Errors on storing output to a file

I wrote my first ansible program and trying to output a file to a new location on my linux box. Failing at the syntax probably. I would like the output of the file (show version) to dump into a new ...

Cannot ping from host to host on the same internal network vmware

I am simply trying to create two Windows 8.1 Desktop VMs and test network connectivity between the two without binding the network/vSwitch to a physical NIC. I created a standard vSwitch and set the ...

Statistics on IT incidents in Unix and/or Linux environments [closed]

I am interesting in what are the possible most common incidents (i.e. service down, file system full, cpu spike, memory full) admins face in day to day Unix/Linux environments administration. Are ...

ipv6: low level technical explanation of Stateless address autoconfiguration

I have a clear understanding of broadcast, DHCP and general network configuration for ipv4. I'm looking for a low level technical explanation of network configuration for ipv6. Some of the terms that ...

Why does Linux need a routing tables [closed]

I am confused with probably an elementary question: Why does Linux (SUSE in my case) needs a routing table? Why does it have to know about its networking mask? As far as I understand my host has a ...

Is it possible that these two lsof rows represent the same tcp connection at different times?

The first line is a connection to postgres: COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME java <procid> <user> 3642u IPv6 3276141 0t0 TCP <h1>:48568-><...

Machine not communicating to gateway which is a layer 3 switch

I have created VLAN 400 in a switch, added ports to that VLAN.Connected one interface of that VLAN to a L3 switch and given IP(10.210.2.1/23) to that interface of the L3 switch. Now my problem is that ...

Centos7 - link up, but no DCHP, unable to bring up next working interface

I have following configuration: server has two network interfaces, both are attached to switch (and will become LOWER_UP after been made up). One of those interfaces will have DHCP server with a lease....

How to route ipv6 to an openvz container?

My hosting provider, OVH, offers me a /64 ipv6 block. I'm pretty new to ipv6 and a bit of a newbie in networking in general. I was able to route an ipv6 on my proxmox server by properly configuring ...

Giving the VM an own ip address

I have a dedicated server running Ubuntu at a hosting provider. I already configured OpenVPN and VirtualBox and installed a Windows 7 VM using VirtualBox. The server has the following interfaces: ...

Best Linux Distro for Thin Client [closed]

I am in the process of deploying a new software system at my company. The sysreqs suggest using terminal services to access the program, rather than running 15 individual installations. We have ...

Bind DNS Problems to host a domain

I own a vps (Virtual Private Server) and have bind dns installed with apache, php5, and more through webmin. I want to configure a domain techmc.net for the on the Public web. How would I configure ...

ISP - Connecting Devices without rebooting modem

Our business currently has multiple static IP's from one of our ISP's. How everything worked in the past and up to this point, is that when we needed to plug a device into our network (switch, ...

Seamless roaming with Mikrotik routers

I need to cower broad area (>1x1km) with WiFi connection that won't be interrupted while clients are moving from one AP to another. And wiring APs with ethernet is strongly undesirable (AP setup is AP+...

Kubernetes - Best Practices for Physical Network Segmentation

Based on the following design constraint, does anyone have any best practices or recommendations regarding how to deploy Kubernetes across multiple network zones? What is the most common and accepted ...

VirtualBox NAT: ICMP works, TCP doesn't work. [migrated]

I am using VirtualBox 5.1.8 (and 5.1.18) on Windows 7 with guest Kubuntu 16.04 Set up: Guest has only one network interface with mode = NAT Windows Firewall is Off (all profiles, all interfaces) I ...

Virtual network

I am not so skilled at networking and I need to setup things on a server from online.net... I tried to hack a bit, but I'm not quite sure to understand what I am doing and I can't get things to work ...

Two adapters communicating on same subnet

I have two sensors that each provide approximately 1Gbps of data and have static IPs on the same subnet. I have one PC with two 1xGbps adapters that I am using for processing the incoming data (OS is ...

Ubuntu 14.04 + libvirt KVM, 3 physical nic, 3 external ip, 3 subnet + internal network HOW?

i have an Ubuntu 14.04 LTS server with 3 nic, 3 external ip from 3 different subnet with 3 different gateway. I have installed libvirt KVM and two Windows 7 64-bit guests. The eth0 (1.1.1.1 with ...

Connecting to same router over multiple ethernet ports

I have a Debian Stretch server with a network card. I want it to connect to my (normal configured standart DHCP) Router. So normaly i would say something like iface eth0 inet dhcp. But i have a ...

Windows 10 hosts + Ubuntu VMWare + Iptables [closed]

I've been trying to set up a firewall on linux with iptables in a virtual machine(Laptop). The goal is to manage all traffic inside my home network. The configurations i'm using are the following: ...

No connectivity between clients on the same interface

I'm having a problem configuring wireless interfaces in Linux. For some reason, traffic generated by wireless clients destined for other wireless clients on the same interface gets dropped (i.e. arp ...

Why first hop of traceroute is not the default router?

default route is: ip route show: 10.0.0.0/23 dev eth1 proto kernel scope link src 10.0.0.150 default via 10.1.1.1 dev eth0 metric 100 And traceroute www.google.com traceroute to www.google....

How to build an open source self healing network? [on hold]

I want to build a self-healing network for my School. I would like to have 1 server and a few clients they download the Windows image from the server and starting it. So after a restart, we have our ...

Group Policy is not applying or being dected by certain users on the same doman

I have recently been experiencing an issue when attempting to push out Group Policy updates. The updates I am attempting to apply are basically just updating parameters in .txt file that resides on a ...

OpenVPN Server PacketLoss

I have an OpenVPN server (Debian 8) OpenVPN 2.3.14 x86_64-pc-linux-gnu. Today I have realised packet losses. My server is on TCP port 443. Ping statistics for 144.76.41.103: Packets: Sent = 1135, ...

Am I understanding right about linux bonding and switch?

If there are one server and one switch, if the switch dies, service on the server down. So there are normally two switches, and the server should be connected to the two switches, therefore there ...

Any way to make separate OpenVPN connections use separate gateways?

I have a bunch of private networks, all on the 172.XXX.XXX.XXX IP space. When I connect via OpenVPN sometimes the VPNs end up connecting through the same gateway which only allows traffic from the ...

MySQL connection timeout on Fedora

I'm having issues when connecting from Linux to a MySQL RDS (AWS) instance. I'm using the mysql command line client to make connections to remote database servers. The initial connection is fine, and ...

How to access the same IP using different network interfaces [migrated]

I have three wlan interfaces attached in my RaspberryPi: wlan0 wlan1 wlan2 Each of them is connected to the different SSID: gopro-0 gopro-1 gopro-2 GoPro cameras are set as a WiFi router, have ...

How does switch know which switch to send data?

For example SW1 / | \ server1 SW2 SW3 | | \ server2 server3 server4 If server3 send data to server4, SW3 ...

ARP request being sent to external IP addresses

I have an Ubuntu 16.04 machine. Here I create a virtual tunnel (tun) interface and make it the default route so that all traffic pass through it. I have a C application listening on this tun interface ...

CentOS 6.8 ip & ifconfig provide different results for IPv6

Am having a weird issue with my CentOS 6.8 I notice a difference between the results coming out of both commands ip -6 and ifconfig. ifconfig is showing more ipv6 addresses Also some applications don'...

Experiencing high latency with server without any server load nor local router latency

I am experiencing a very weird issue and it is hard to synthesize in a simple sentence, so I am sorry if the title of the question is rather shady. So I have a dedicated server running with the ...

How can I route traffic from VM to remote server using hosts vpn client (Anyconnect)?

My goal is to set up application communication between a client and a server. The client is on my Windows Server 2012R2 VM that resides on VMWare Player 12. The host is a Windows 10, on this one I ...

Iptables and tcp attacks protection rules

My current iptables (only ipv4, ipv6 is turned off on this server) looks like this: -P INPUT DROP -P FORWARD ACCEPT -P OUTPUT ACCEPT -A INPUT -i lo -j ACCEPT -A INPUT -m conntrack --ctstate RELATED,...

LACP bond work intermittently on Cisco N5000

Our clients are using Centos 7.1 and 7.3. They are two 10GB card bonded to make a 20GB link. Each of the network card is connected to a pair of Cisco N5000 switch. While running cp or iperf, I can see ...

Does iptables not work with long-named network interfaces?

I used to configure iptables to forward packages between different network interfaces on a muli-network-interface-server. So long, it worked fine until I updated my server to Ubuntu 1604. Ubuntu ...

Does bonding 3 1G NICs into one make a 3G NIC?

For example, I have 3 NICs (1GB) and make a bonded NIC. Do I get a 3GB NIC? Should I connect these 3 NICs into 1 switch? If one NIC dies, do I still have the network between server and switch alive? ...

Host with bonded interfaces on one subnet, set up bridge with a different public subnet for VMs

I am setting an Ubuntu host server (16.04) with a number of KVMs running on it. The host server has 4 physical NICs which are bonded in pairs to access a public facing network, and a private network. ...

tenants are building their own server in the share office, how do I give out specific ports to them?

Scenario: A couple of companies are sharing an office as a tenant. Since I don't have much knowledge in networking, I'm not quite sure how to configure the setting of switches and routers. However, ...

What network setting could impact iperf3 results?

I am making some bandwidth tests to set a baseline for some other tests and I have a behaviour I cannot understand. The tests are done with iperf3 on Linux (with and without -R to get both up- and ...

Isolate PC on my network

The scenario I have is that I work from home for a few clients. For one of these clients, I have purchased a separate machine, and use this for any activities related to this client. From this ...

Https on iis not working with domain name of ip address

Using Windows 2012 R2 Standard server with IIS. Windows firewall has preset rules World Wide Web Services (HTTP Traffic-In) and World Wide Web Services (HTTPS Traffic-In) enabled. The server has one ...
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