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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How virbr0-nic is created?

How can I create a virtual network interface like virbr0-nic? I am trying to find a way to create a NIC like virbr0-nic but everything which I can find on the Internet is how to create an interface ...
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12 views

Is IP range or vLAN traffic mirroring possible with Linux?

I am dealing with a network monitoring issue in a medium size hosting platform (10 Gb). Some of the network devices can only do 1-2 SPAN ports. In order to get some more flexibility I'd like to use a ...
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23 views

Forward all traffic when connected to a hub

I have a Ubuntu with two NICs. eth0 is connected to a hub and eth1 is connected to Internet. eth1 is used to do a point to point VPN using openVPN. So I have a tun0 interface. the VPN tunnel endpoints ...
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0answers
19 views

How does the captive portal redirect work behind the scenes

As a project I am building my own captive portal web pages for "unauthenticated" users. Those are users that have not hit a button on my captive portal page. I want this to be out of band (like a ...
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1answer
42 views

How to disable ip_forward for Ubuntu server

This is the state of my server right after booting: root@vzu01-ubuntu:~# cat /proc/sys/net/ipv4/ip_forward 1 There is no other enabled ip_forward configuration: root@vzu01-ubuntu:~# grep -r ...
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2answers
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Siege: descriptor table full sock.c:119: Too many open files

I am trying to make a stress test in my own server using siege with the following command: $ siege -c 500 myweb.com/somefile.php But I get this error: [error] descriptor table full sock.c:119: Too ...
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0answers
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Static ips aren´t working in ubuntu virtual machines

I want to set a static ip to a ubuntu vm client and other static ip to other ubuntu vm server. Im doing this like this: sudo gedit /etc/network/interfaces Then in the ubuntu vm client file: auto ...
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1answer
25 views

How to create virtual networks by using libvirt?

I have installed qemu/kvm and have tried to create some virtual machines and network them together. What I would like to achieve is 2-3 virtual machines in their own private network (e.g. ...
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1answer
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How to properly permanent enable ip forwarding in Linux with systemd?

I try to enable ip forwarding (between enp0s3 and tun0 interfaces) and write net.ipv4.ip_forward = 1 in /etc/sysctl.conf. After restart I have $ cat /proc/sys/net/ipv4/ip_forward 1 But forwarding ...
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28 views

what is the “ip route” equivalent of “route add -host” in linux?

Specifically, route add -host allows me to specify the host via hostname to add a route to a host, e.g., route add -host www.google.com gw 192.168.1.1 However, I cannot find a way to do this using ...
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1answer
3k views

Error while bringing up eth1

I'm getting this error while bringing up my network card: (process:2550): WARNING **: _nm_object_get_property: Error getting 'State' for /org/freedesktop/NetworkManager/ActiveConnection/3: (19) ...
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1answer
34 views

Default gateway and ARP confusion

I have the following configuration (I'd post a pic but not enough rep for more than 2): PC1 (10.0.2.10/24) and PC2 (10.0.2.137/29) are connected to a hub, which is connected to a router on interface ...
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0answers
17 views

Add new subnets to KVM Host

I need to assign a handful of /27 subnets to my KVM host node (Centos 6). I routed them correctly at the Cisco switch, so that's all go. Traceroute & ping works fine on gateway on each subnet, ...
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2answers
32 views

Percentual dynamic bandwidth control with tc

Does anyone know if tc (iproute2) can be used to percentually divide the currently available bandwidth? We're on a GPRS connection on which the available bandwidth changes frequently. What I want to ...
3
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1answer
49 views

Find network percentage of NIC [closed]

So I have created a Linux resource monitoring tool that pulls various resource information. One of the fields I am trying to pull is the percent of network throughput on my NIC. So if I have a 1 ...
2
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0answers
29 views

network access issue and triage

We have two hosts in same vlan with same route rules. One of them is able to connect to an outside IP while on another I get failed: Connection timed out when testing the connectivity through netcat. ...
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0answers
16 views

iptables/nat/prerouting ignores UDP packets?

The same effect on many servers with various kernel versions. There are multiple Iptables DNAT rules: iptables -t nat -A PREROUTING -i eth0 -p tcp --dport 12345 -j DNAT --to-destination ...
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0answers
19 views

How do I properly configure KVM

I have a remote dedicated server on which I have installed KVM. When trying to create my first virtual machine I am unable to ssh to the machine. I assumed that I needed another ip address so I ...
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1answer
23 views

Routing via sub-interfaces not working?

I'm trying to isolate outbound network traffic to a specific target for metering purposes, so I thought I'd route it via a dedicated IP address. In order to achieve this I have setup a subinterface ...
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2answers
37 views

Linux Hostapd registers as WEP, but I want WPA2-PSK

as usual to respect the community, I have traversed a bajillion articles and re-read the manual and still can't seem to get past this issue. I'm trying to create an access point in Linux(linaro on a ...
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1answer
22 views

Asterisk hacking defence: “Call setup” in tcpdump from denied IP number

I am running Asterisk 11.7 on Ubuntu for my small business. These last days someone could access the server and make all phone extensions ring in regular intervals. I would like to understand how that ...
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15 views

ARP cache getting null mac over a bridge

I have an interface eno1 and a bridge br0 $ ifconfig br0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500 inet 192.168.250.53 netmask 255.255.255.0 broadcast 192.168.250.255 ...
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14 views

overlapping subnets - how to give one precedence?

I have Linux devices with a single ethernet interface and two IP adresses. The first (eth0) is statically configured to 10.1.1.146/24. The second (eth0:1) is configured via DHCP and it may happen ...
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0answers
17 views

SSH stops responding on all AWS EC2 instances at the same time

I've noticed SSH connections hang on all my EC2 instances (ubuntu), and eventually fail (with 'broken pipe') around the same time, 7 to 9pm in the evenings. HTTP and telnet continue to function ...
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How do I force specific interface to use different driver in RHEL?

We have Dell Poweredge 630 server which has 2 NIC Interface. We bought Intel's FTLX85.. module for those 10Gbit ethernets. 2 interfaces were using bnx2x driver of Broadcom. I installed Intel's ixgbe ...
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1answer
18 views

Network interface fails to come up under heavy traffic

We're investigating an issue with our kit, which is an IP camera running Busybox Linux on a Ti-Davinci SoC. On one particular site there is a lot of network traffic (over which we do not have ...
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2answers
27 views

How safe is IPtables whitelisting?

I am deploying some VPS and of course, security is a big concern. I read that IPtables whitelisting is the best way to safeguard your machine. So I set up the follwing : echo "Flushing rules" ...
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9 views

http://127.0.0.1 returning 401 Unauthorized [migrated]

I have a CentOS 7 box and have a service running on port 32400 (Plex Media Server) which is trying to pull some information via HTTP to http://127.0.0.1:32400/library/changestamp but a 401 response is ...
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0answers
9 views

Setting up bridge for domU to be accessed from external network(internet)

I am trying to setup virtual guests(PV) using xen 4.4 (xen-tools) on debian 8.3. Problem is that I fail to configure bridge properly I guess ^^. I have setup an interface xenbr0 that uses same IP ad ...
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0answers
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How can I create separate/isolated regions on a home network? [migrated]

I currently have a flat network at home. My boradband router comes in and is connected to a switch, which supplies the Ethernet drops within the house. I also have a wireless router connected to the ...
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2answers
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VMWare and Turnkey Linux appliance can't access network

I have a VMWare ESXi cluster running many Windows and Linux VMs perfectly. I have installed the Turnkey Linux Redmine appliance, and am having a lot of trouble getting the networking to work ...
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1answer
21 views

CentOS7 Network Bridge Fails on boot until cable unplugged and plugged back in

I have a problem with a brand new CentOS 7 server I am trying to set-up. I have set-up a network bridge as per instructions on the redhat documentation website and it all works great until I reboot. ...
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13 views

Adding an ip6ip6 tunnel in Linux fails silently

This is on Debian Wheezy. I'm trying to add an ip6ip6 tunnel like this: # ip -6 tunnel add v6tunash01 mode ip6ip6 local 2a02:27f0:2:246::2 remote 2a02:27f0:2:306::2 No output. But the device ...
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Use ubuntu 14.04.3 box as a wireless access point, no dhcp server and eth0 to wlan0 bridging [migrated]

I noticed that I had a 300Mbps N wireless adapter laying arround so I decided to use it in my ubuntu server to expand the range of my local nework, that server is being used as a samba and ftp server, ...
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5answers
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How to persist ethtool settings through reboot

I would like to turn off tcp segmentation offload on a CentOS5 server. Using ethtool the command is ethtool -K eth0 tso off However, this setting only persists for this session. How can I make it ...
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0answers
9 views

How to configure Spark client running in a Docker container for two-way communication with a remote Spark cluster?

spark-submit seems to require two-way communication with a remote Spark cluster in order to run jobs. This is easy to configure between machines (10.x.x.x to 10.x.x.x and back) but becomes confusing ...
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1answer
2k views

How to configure VXLAN over linux bridge?

I am using Ubuntu 14.04 which support VXLAN configuration. Currently I can add a VXLAN interface such that: vagrant@ubuntu:~$ sudo ip link add vxlan1 type vxlan id 1 group 239.1.1.2 vagrant@ubuntu:~$ ...
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45 views

Why is CentOS 7 ignoring NETMASK?

I have a networking issue that I eventually tracked down to an incorrect network prefix setting. ip addr is reporting that the current prefix is /8 when it should be /24. However, when I look in ...
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10 views

Can Spark be configured to listen on multiple network interfaces/ip addresses?

The nodes in my Spark cluster have two network interfaces each, one public and one private. Using the SPARK_MASTER_IP environment variable, I can configure Spark to listen on port 7077 on one or the ...
0
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1answer
1k views

Improving TCP performance over a network with small packet loss

I’m trying to improve my TCP throughput over a “high delay network”, with some packet drops, between Linux machines. I set tcp_mem, tcp_wmem and tcp_rmem to “8192 20530752 20530752”. I set rmem_max, ...
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0answers
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Bridged qemu machine cannot receive packets, these are dropped [migrated]

I've created virtual machine (ppc) with bridged interface (using bridge helper) on archlinux. Machine can send packet out, but cannot receive anything. I can see packets (dhcp discover,request and/or ...
0
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0answers
36 views

Git Failed to connect to 127.0.0.1 port 8087: Connection refused

I'm installing the array database rasdaman, when I go to the step "make" , it begins to: git submodule update --init --recursive Cloning into 'third_party/googlemock'... but I don't know what ...
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0answers
21 views

Sending duplicate packets to the wan ip address

I'm in need to send duplicated packets to the remote host (wan ip address). I'm aware that -j TEE would do just that on the LAN, but what about WAN? iptables -I POSTROUTING -t mangle -d x.x.x.x -j ...
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2answers
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IPTABLES: Route outgoing http requests to eth1

I am trying to route all outgoing HTTP requests LEAVING my server to go through a proxy (tinyproxy) on another server. I want the transmission to the proxy to use our LAN which is on eth1. No matter ...
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0answers
33 views

Unable to bind a large Ipv6 block in Centos 7

I have ipv6block xxxx:xxxx:xxxx:xxxx::/64 block to bind to my interface on centos 7. I have tried to use: ip route add local xxxx.xxxx.xxxx.xxxx::/64 dev lo That was according to the anyip ...
0
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1answer
15 views

PPTPD-server split tunnel

Normally the client has to set up the VPN connection to be a split tunnel (not routing internet traffic trough the tunnel, but still have access to local resources), but is this possible to define on ...
0
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1answer
32 views

PPTP with restrictive access to local network for connecting clients

How can I restrict access to my local network for VPN-clients connecting to a VPN-server (PPTPD) located on my network? I would like clients to be able to connect to my linux node running a VPN ...
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2answers
3k views

WMI: wmic linux agent query error: NTSTATUS: NT_STATUS_ACCESS_DENIED

Myself new to wmic and keep trying for a long time with default agent query approach. wmic is linux based WMI tool to talk to windows WMI agent. While trying to fetch data with wmic from nt(win7 with ...
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2answers
3k views

disable a network interface on booting ubuntu

I use ubuntu 12.04. I need to boot with one of the network interfaces 'eth1' down. I tried adding sudo ifconfig eth1 down to /etc/rc.local However it seems the interface is brought up and ...
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1answer
137 views

DNAT port range with different internal port range with Iptables

The standard way of DNATing a single port to a different port on an internal network is something like that: ip(6)tables -t nat -A PREROUTING -i wan0 -p tcp --dport 80 --to-destination 10.0.0.1:8080 ...