Linux Networking refers to any networking function performed by a server running Linux. A Linux server operating as a router or firewall are the most common applications.

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16 views

How to deploy video streaming with central storage server? [on hold]

I'm looking at building a video streaming service containing mostly video clips in 10~15 mins range in 480~720p. I plan to scale it in the near future, and want to do proper planning before making ...
0
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1answer
17 views

Restarting network interfaces that have changed with ansible

I've got an ansible role that - name: add virtual interface configs for vlan template: src=ifcfg-eth.vlan.j2 dest=/etc/sysconfig/network-scripts/ifcfg-{{ item.device }} with_items: "{{ ...
0
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0answers
9 views

Firewall-Rules on Proxmox-Node cause VPS to be offline

I'm using proxmox to virtualize some small machines based on KVM. To do so I created the following network-config on the KVM-VPS: # This file describes the network interfaces available on your ...
0
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0answers
10 views

IPSEC VPN point-to-site connection works but remote network is not rechable

I have a probelm with ipsec configuration. I have to connect to remote network (client! to site), where is Fortigate firewall. On left side (where I have access, this is my dedicated server), I have a ...
0
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0answers
19 views

Large payload - connection get's Hung with CLOSE_WAIT or LAST_ACK state

We have a webservice client which posts data to a 3rd party Webservice. We are having an issue when the payload is a bit large (Around 600KB) xml. Once we pay the process hangs forever. The Netstat ...
0
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0answers
36 views

dhcpd class match on hostname or mac address

We are running DHCPD 4.1.1-P1 on a RHEL 6 server. Currently we have 1 class defined for deny purposes. We now have a need for a class match to allow all devices that match a variable and deny ...
0
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1answer
58 views

Multiple Gateways for Single Subnet

Right, this might be a long one, so bare with me... I have 2 machines, lets call them local1 and cloud1. local1 has 3 Nics: 2 connected directly to cable modems with public IPS (call them eth0 and ...
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0answers
21 views

etho:0 not working and lshw -C network says *- Network Disable

i was trying to add IP alias but i cannot add etho:0 because it is not working. $ lsusb unable to initialize libusb: -99 $ lspci -nn | grep 'Wireless Brand' pcilib: Cannot open /proc/bus/pci ...
0
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2answers
20 views

Check on Linux certain port is occupied

I'm writing a script that will spin up server that want to use certain port number. In some occasions this port is occupied. I want to know how to check it in bash so I can react in proper way. How ...
2
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0answers
35 views

Possible to force TCP window scaling to a higher value?

Is it possible to increase the TCP window scaling factor on Linux (CentOS 7.2)? I have a long fat network (100 Mbps) from London to Chicago and I'm getting 16 Mbps throughput in TCP on an sftp from a ...
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0answers
16 views

Connection activation failed

After a kernel update I had to re-install the network drivers and found that the bridge no longer functions. Does anyone know how I can repair this situation? [root@kvm01 tmp]# ifup br0 Error: ...
0
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1answer
38 views

Resolve NetBIOS names without full qualification

I am connected to my office VPN and I can successfully RDP into my computer using the fully qualified name for it PC00001.myofficevpn.plc. When I try to connect using only the hostname PC00001, I do ...
0
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0answers
15 views

Smaller subnet mask to “merge” VPN-connected LANs?

I have two LANs connected to different internet connections (in different cities, in fact): ISP1 -> LAN 1: 192.168.10.0/24 ISP2 -> LAN 2: 192.168.11.0/24 On each LAN is a router. Both routers ...
0
votes
1answer
26 views

Routing only internal traffic to VPN

When I connect to the VPN, I don't have access to the internal addresses of my office. If I issue a: route add default dev ppp0 I can finally ping the office's machines but all my internet traffic ...
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0answers
33 views

Port forwarding/ssh [on hold]

I have a question about port forwarding. In my case - I need serverB to be able to communicate with serverA over port 9090. The problem is that serverB can't not connect to serverA over this port. ...
1
vote
1answer
23 views

Tunnel / Forward connections on server 1 to server 2

I have now spent some time researching, but I haven't found a working solution to the following problem: I want to tunnel any requests on server 1, port x to server 2, port x. The port stays the ...
0
votes
1answer
22 views

frequent delay of 5-10 sec in sending commands from putty redhat. Why?

When we type a command from putty, it suddenly hangs for a period of 5-10 sec or more, but the commands are sent to terminal later. So seems to be a latency which occurs frequently. But, I might be ...
0
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0answers
8 views

Dhcp id: user: no such user , dhcp start error Centos6/ rhel 6

i installed dhcp server using rpm o rhel 6 when iam starting #service dhcpd start/restart i am getting Failed to start dhcp, even when i am running #id dhcpd getting error no such user (no group ...
0
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0answers
20 views

What is the network connection speed between two containers communicating via a virtual bridge running on the same host?

Does a virtual bridge (added to /etc/network/interfaces) limit the transfer speed of data from the memory of one lxc/docker container to another? For example does the memory throughput drop to that ...
0
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0answers
35 views

Configuring vxlan unicast in linux

I want to try vxlan unicast and configured following configurations in Fedora 23 VM1(enp0s8) ========= (enp0s8)VM2 ip address add 100.1.1.1/24 dev enp0s8 ifconfig enp0s8 up ip link add name vxlan42 ...
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0answers
48 views

Network Unreachable when configuring static route

root@vpn:~# route -n Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface ..... 10.0.0.0 10.0.0.1 255.0.0.0 UG 0 0 0 ...
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1answer
57 views

get mac address and replace from a file [closed]

I have two interfaces ethernet: Example: ifconfig | grep direcciónHW enp2s0 Link encap:Ethernet direcciónHW b8:2a:72:01:01:02 eno1 Link encap:Ethernet direcciónHW 9c:d2:1e:01:03:04 I ...
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0answers
28 views

linux how to change metric of default route

I just installed fedora 23 in vm, there is two net card, host only (10.xxx) and bridge (192.xxx) now I can connect to vm with ssh, but can't access to internet. if I disable the host only network ...
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0answers
35 views

Unable to open www.debian.org [on hold]

I have a problem with a Debian virtual machine that cannot reach the debian website. The virtual machine have a public ip address directly assigned on the eth0 interface. HTTP/1.0 root@web1:~# curl ...
0
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0answers
18 views

Bridge not functioning as expected

I want to put a listening machine in my test network using a bridge setup. I now have the following test setup: PC1 (192.168.40.250/24) --- Bridge (192.168.40.160/24) --- PC2 (192.168.40.132/24) ...
0
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1answer
35 views

Linux server failing to send SYN/ACK after receiving SYN remotely, works locally

Problem: A server process can be accessed by a device on the LAN or by the server itself, but it cannot be accessed outside the LAN (port forwarding is configured correctly as the server does receive ...
12
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5answers
1k views

How to simulate DNS server response timeout?

I need to test an application's behavior when it can't resolve a hostname due to a timeout. Setting nameserver 127.0.0.1 in /etc/resolv.conf didn't work: the relevant functions return immediately with ...
0
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0answers
25 views

Public port forwarding from site A to site B (connected through a site-to-site VPN)

I have two distant offices (site A and site B). The two offices are connected through a site-to-site OpenVPN solution (the VPN servers are independent of the office routers, each router has a static ...
3
votes
1answer
123 views

Create a multi-homed linux load balancer with two internet connections and one LAN connection

OK,... this has possibly been answered, unfortunately, I have not found anything that looks like it might be the resolution. Ive looked at these pages and they have some useful information, but not ...
0
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0answers
30 views

Configuration SNAT iptables in ubuntu

I have 2 PC be created by VMWARE 1. PC1 (make iptables router): eth0 's IP: 192.168.1.4/24 (network connection is bridged) eth1 's IP: 192.168.2.2/24. (network connection is wmnet9) 2. PC2: ...
0
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1answer
44 views

Virtual NICs and Host only adapter in KVM

How can i create virtual network adapter like a physical eth0 in KVM? As I lack physical NICs. Also I need a Host-only adapter just like in VMware to connect two VMs in KVM. What is possible solution ...
0
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1answer
30 views

debian networking does not restart properly

I have a Debian 8 machine, where I've configured two VLAN interfaces in /etc/network/interfaces. Now I've deconfigured it (deleted information from interfaces file), restarted networking, and now it ...
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0answers
40 views

How do I resolve hostnames on the local network in Linux Mint? [migrated]

Nothing on Google, other questions on the stack websites or anywhere else seems to answer my question. Let's pretend that my Windows laptop is using the device name mylaptop. Other Windows' devices ...
0
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1answer
40 views

Network Related Apache 2.4 403 Authz Error AH01630

I've never seen this style of behavior before. If I access this site on most networks it works. However if I am on-site of the client I cannot pull up the site. TWC Home, works fine. ATT Cell Data, ...
1
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0answers
50 views

How to connect to a service on a local network machine whch which only listens to localhost?

I have a service which only listens to localhost on port 7400. There is a service running on a windows and an ubuntu machine on a private network. How can another computer on the same network ...
2
votes
1answer
47 views

Simulate massive network traffic [closed]

We want to stress test our pfsense box with a massive amount of connections and traffic. Right now we are using iperf, but reaching a number of more than ~300 parallel connections the test clients ...
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votes
1answer
45 views

Connected to router but without internet [closed]

My Linux Mint 17 box is connected to a router via eth0, of which is connected to the internet. However, my box cannot access websites or ping google.com etc. I am sure the problem is with the DNS ...
0
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0answers
26 views

Transparent Bridging of Internal Network in KVM

I am deploying a following topology of virtual Honeynet in KVM.Topology of Honeynet I have two network interfaces eth0 and eth1 ony my System. Problem I am facing is to implement transparent bridge ...
-2
votes
1answer
68 views

If a server is headless (CentOS 7) is there a way to make the GPU used as an extra CPU core?

I've got a server with centOS that has no graphical interface. I only connect to it via ssh. As a result, the GPU is probably not used for much. I'd like to make the server use it as an extra CPU ...
0
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2answers
36 views

how to execute a script Rhel 7 at booting time?

I am trying to execute a shell script on RHEL7.1 when the machine starts. As in ubuntu, Upstart scripts (in /etc/init/) are used to execute any scripts or to start any services at boot time, is there ...
1
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0answers
32 views

Proxmox: Add IPs from different subnets to LXC-container

I am using proxmox 4.1. If I add IP-addresses to my CentOS-7-LXC I can only do that if this IP is from the same subnet. If I'm using another subnet with another gateway the container is not pingable ...
0
votes
0answers
27 views

IPv6 interface not responding to neighbor solicitations, DHCP involved too

ip addr shows: 2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000 link/ether 02:6d:5e:86:29:49 brd ff:ff:ff:ff:ff:ff inet ...
0
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0answers
37 views

Debian iptables load fail

I Have Debian 8 Jessie and I have installed iptables, but it's not correctly. I can add rule just like: iptables -A OUTPUT -s 212.50.128.0/19 -j DROP but it's not working. iptables -L command works ...
2
votes
2answers
87 views

why Ethernet MTU size is 1500? [closed]

Can somebody explain that why the Ethernet Maximum Transmission Unit was chosen to be 1500 bytes (why exactly 1500) ? It might have some historical reason.
0
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4answers
103 views

How do I find out linux gateway IP address?

I have CentOS 6.7 with two Internet connections eth0 - dynamic IP address and dynamic gateway via DHCP (controlled by NetworkManager) ppp0 - dynamic IP address and dynamic gateway (configured with ...
0
votes
1answer
45 views

Setting default gateway on CentOS 7 and showing it using route and netstat -r

I am following a tutorial found here on how to setup a gateway for each adapter and also a default gateway: http://linux-training.be/sysadmin/ch22.html But when I run the commands $ route and $ ...
1
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0answers
17 views

How to ensure via shorewall that the network is closed at boot time?

I use Shorewall (on Ubuntu 16.04) and would like to ensure that between the start of the boot process and the moment iptables rules are applied the network is in a closed state. There provision for ...
0
votes
1answer
30 views

Iperf3 keeps hanging when running UDP test

I wrote a Python program that runs iperf3 in a for loop with different datagram sizes. I am using Python's subprocess.call function to run iperf3 like this: iperf3 -u -c 185.82.21.60 -b 100M -t 5 -l ...
1
vote
1answer
37 views

How to redirect traffic through IPv6 IPSec (strongswan) gateway?

I'm trying to set up IPSec secured connection to the gateway. Have three hosts: A: eth1 - fec0:1::1/64 B: eth1 - fec0:1::2/64 eth2 - fec0:2::2/64 which is gateway between A and C; forwarding is set ...
0
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1answer
23 views

ksoftirqd/0 hit ~100% cpu usage led network lag

I run an app on CentOS6(e5-2667v2 x2 with 128GB RAM, 1000M network interface), When network load up to ~300Mbit/s, the ksoftirqd/0 process hit ~100% cpu usage, and begin loss packet. How can I do?