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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Supersede default route

I have two network interfaces eth1 and wlan0. I would prefer all outbound traffic to go through eth1 before wlan0, but if eth1 is not up, and then wlan0 should handle the traffic. Both interfaces get ...
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2answers
11 views

In an OpenVPN network, Windows clients cannot access the host and other clients

I have set up an OpenVPN network and I'd like to let every client in the network be able to connect to each other, ie. servers 10.8.0.1, 10.8.0.2 and 1.8.0.3 should be able to communicate over VPN and ...
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0answers
8 views

SolusVM KVM-Virtualisation: Add IPs from multiple Subnets to VPS

I would like to add IPs from different networks to my SolusVM-KVM-Virtualisation. The virtualisation is working fine and is accessible via 81.95.3.xxx. But other IPs I added (82.199.134.xxx) are not ...
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0answers
14 views

Rsync does not delete destination files [rsync protocol / module]

An automatic backup script executes the following rsync command to sync a local directory tree with a remote one: env RSYNC_PASSWORD=$rsync_password rsync -aqrxz --delete --timeout=30 \ ...
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3answers
31 views

How to detect what's blocking my incoming traffic on Ubuntu 14.04 LTS, if it's NOT iptables and NOT EC2 Security Group?

I have SSH root access to an EC2 instance. It's Ubuntu 14.04 LTS. I have nginx web server listening on all interfaces on port 80 TCP. It's accessible from this server but not from the outside. ...
2
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1answer
61 views

Multicraft: Port Forwarding through a GRE Tunnel

For the past week I've been attempting to protect a server from DOS attacks by utilizing a GRE tunnel from a VPS to a dedicated machine without much success. Visual: User --> VPS --> Dedicated ...
2
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3answers
2k views

How can I achieve OpenVPN client routing without NAT on Linode

I've set up an OpenVPN network, and it is working properly in the sense that I can access the inner/LAN machines from the remote client. However, my problem is that all traffic from the remote ...
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0answers
14 views

CentOS 7 on Virtualbox [on hold]

Thanks in advance. I have a virtual box machine running CentOS 7. The host is my mac and the I'm using bridge adapter mode for the VM. Looks like i'm unable to install (yum) updates or even (yum) ...
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2answers
19 views

What is causing the famous “broken pipe” when I use tmux inside an SSH session?

Scenario1: I SSH from my employer (OSX Yosemite SSH client) to my home server (Debian stable) and (re)connect to a tmux session. If I leave the terminal inactive for a while (~20minutes), it seems ...
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0answers
29 views

Iptables what does --match do? [on hold]

I don't exactly understand what the --match option does. I've added a rule for accepting connection from a specific host on a specific port with: $ iptables -I INPUT -p tcp -m tcp -s 70.85.189.123 ...
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0answers
27 views

GRE Tunnel Collapsing in One Direction

This is a related question to another thread I posted. I'm having an issue where my GRE tunnel is collapsing in one direction, but can be reopened by ping the other server using the GRE Interface. ...
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1answer
36 views

How to configure a Linux network namespace that allows UDP broadcast

I'm trying to use the ip netns family of commands in Linux to create a network namespace in which I can run a program that uses UDP broadcast. I do not need access to the Internet, or any interface on ...
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0answers
277 views

iptables - hashlimits, why it calculate all to seconds

I've tried to set 'synflood' limits with hashlimits, those are my snippet of rules: iptables -A SYNFLOOD_CHECK -p tcp --syn -m hashlimit --hashlimit-above 10/s --hashlimit-burst 6 \ ...
2
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0answers
10 views

What are the advantages NAPI before the IRQ Coalesce?

As known there are two approach to avoid some overheads of hardware interrupts in highload networks, when there are too many hardware interrupts, that switching to them takes too much time. It is very ...
1
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1answer
26 views

How increase classes in HTB? [closed]

I am trying to setup a traffic shaping by HTB and tc. I have 70,000 users and I want to control the bandwidth of each user, so I create 70000 classes, and assign each ip address to a class by ip ...
2
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1answer
154 views

Cannot ping to localhost into CentOS

I'm connecting to my server (Centos 7) with ssh and I try to ping to localhost: ping 127.0.0.1 but doesn't work: ping 127.0.0.1 PING 127.0.0.1 (127.0.0.1) 56(84) bytes of data. ^C --- 127.0.0.1 ping ...
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1answer
21 views

IPSEC stack low speed

I am working on Openswan IPSEC Implementation for Linux-kernel 2.6.35.9 My concern is when i do speed test using IPSEC kernel Images and without running IPSEC service i get speed of 40Mbps and ...
0
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1answer
116 views

How to config Squid SSL bump to let Paloalto PA series firewall recognize App-ID

A Paloalto firewall(PA-2050,POS 4.1x) was capable of recognizing the websites which users are visiting(thru http/https) then flag them with a App-ID and apply application control on the traffic, for ...
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1answer
29 views

measuring network throughput with netperf

I'm doing benchmark test of Linux server using netperf. According to information at networksecuritytoolkit the theoretical max throughput rate for 1514-bytes packets is 117.35 Mbp/s. However I'm ...
2
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1answer
51 views

TCP Upload Speeds Slow to the Internet over LFN

I've got two Linux VMs separated by a 50 mbps WAN connection. There is about 70ms of RTT on this WAN link, so it's got some latency. I've been testing my upload throughput to the Internet from each of ...
3
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1answer
351 views

Split tunneling through two VPNs simeltaneously

I want to run two OpenVPN client instances on an Ubuntu Server 14.04. I have both .conf files that can work independently (both are set to different interfaces - tun0 and tun1). I want to run both at ...
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1answer
937 views

IP setting in CentoOS 6.2x64 by XenCenter 6.2

I have setup a Guest CentOS virtual machine in Xenserver.. I have updated the Xentools but i cannot find the option to config my IP Address which is showing to be 'unknown' currently. All i need to do ...
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2answers
1k views

Untangle VPN setup, how to see internal addresses?

So Untangle is setup as the default gateway at 192.168.100.1/24, it is the authorative DHCP server issuing addresses from 192.168.100.100 to 192.168.100.200 and is successfully connected to the ...
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2answers
38 views

Using iptables or similar to redirect traffic to a proxy

I've searched around for an answer to this question, but it seems like most of what I found wasn't specifically what I wanted to do (mostly redirecting traffic on the same host to squid running on ...
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1answer
15 views

Changing qemu/libvirt default gateway IPv4 IP to something other than x.x.x.1/24

General info: I have a KVM-libvirt/qemu running on ArchLinux; 3.18.2-2-ARCH ls | egrep -i 'libvirt|qemu' libvirt-1.2.11-1-x86_64.pkg.tar.xz libvirt-glib-0.2.0-1-x86_64.pkg.tar.xz ...
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1answer
324 views

Can't start CentOS 7 “network” service

I Can't start CentOS 7 "network" service after disabling and removing "NetworkManager" service. When I check the network service status, it comes up with the following error: #systemctl status ...
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0answers
4 views

How to connect an Android Emulator to a Vagrant Image on the same host? [migrated]

I have a non-trivial application, comprised of a number of web & database servers that reside within a Vagrant image. Port forwarding (with iptables) has been enabled on the host such that I can ...
2
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1answer
26 views

Difference between ip link eth down and ip link dev eth down

What's the difference between ip link set eth0 down and ip link set dev eth0 down ? The difference between the commands does not appear to be documented anywhere.
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0answers
24 views

How to create openvpn tunnel between multiple interfaces between two hosts ubuntu linux

I want to create OpenVPN tunnel between two Ubuntu 12.10 hosts which has two interfaces, say: Host1: eth0, eth1 Host2: eth0, eth1 A tunnel is wanted between: Host1 (eth0) <-> Host 2 (eth0) ...
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1answer
2k 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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3answers
689 views

Debian 7 how are IPv6 link local addresses set?

It seems like when dhclient runs on eth0 I get an IPv4 address from the DHCP server and a Scope:Link IPv6 address attached to eth0: inet6 addr: fe80::a00:27ff:fed0:4d41/64 Scope:Link But I can't ...
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5answers
2k views

tc u32 — how to match L2 protocols in recent kernels?

I have a nice shaper, with hashed filtering, built at a linux bridge. In short, br0 connects external and internal physical interfaces, VLAN tagged packets are bridged "transparently" (I mean, no VLAN ...
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0answers
47 views

opendkim-testkey: keys do not match

How do you produce the 'default._domainkey.drpedroazevedo.com' file? I deleted mine because my key expired and opendkim-keygen did not produce a new one as expected. mlr01 keys # ...
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0answers
21 views

How to config private IPs for IPMI using VPN?

Recently I discovered it is best to protect my IPMI web interface behind a VPN. I went ahead and installed OpenVPN on my server and connect to it using tunnleblink on OSX. The VPN part is all set and ...
0
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1answer
55 views

LXC container clone has no network and SSH stopped

I was having this networking problem with LXC containers (question and answer here:bridging LXC containers to host network with different IP range) and if I have found a solution, I still have not ...
0
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1answer
19 views

Debian-based Infiniband point-to-point Voltaire dual port cards

I have the following configuration: I------------------I I------------------I I I(P0)---------(P0)I I I Voltaire HCA 0 I I ...
0
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1answer
36 views

how to make this bridge to work?

I have posted a similar question at: http://stackoverflow.com/questions/27873819/customising-docker-network-doesnt-work# To simplify the question, let me get rid of docker. This is the network ...
12
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1answer
3k views

Should /etc/hosts contain an entry like '127.0.0.1 localhost myhost.example.org myhost'?

When looking at a variety of Linux and FreeBSD systems, I've noticed that on some systems /etc/hosts contains an entry for the public hostname of the host, but not on other systemst. What is the best ...
1
vote
1answer
35 views

Windows multicast NLB with Linux clients

I'm (on behalf of a client, anyway) having some troubles with Linux accessing a multicast NLB cluster hosted on Hyper-V (waiting for more information on what version, but I don't think the version is ...
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2answers
1k views

How to route broadcast packets from machine with two network interfaces on same subnet

I run RHEL 5 and have two NICs on one machine connected to the same subnet: eth0 192.168.100.10 eth1 192.168.100.11 My application needs to receive and transmit UDP packets (both unicast ...
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2answers
114 views

How do I block incoming traffic from Amazon AWS IPs?

I'd like to block ALL incoming traffic from Amazon AWS IPs. They publish a list of their IP addresses in json format here: http://docs.aws.amazon.com/general/latest/gr/aws-ip-ranges.html I have a ...
1
vote
1answer
85 views

Allow OpenVPN client to push it's own DNS servers, regardless of OpenVPN server's pushed dns?

There is an OpenVPN server running on a Debian and it pushes a DNS in the server config file: push "dhcp-option DNS 8.8.8.8" Is there an option to allow the users to change that DNS servers on the ...
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1answer
36 views

Public IP not responding because routing table…?

Fixed with: /etc/iproute2/rt_tables 1 tble_eth0 /etc/sysconfig/network-scripts/route-eth0 104.000.64.0/18 dev eth0 src 104.000.65.38 table tble_eth0 default via 104.000.64.1 dev eth0 src ...
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1answer
21 views

Why adding a route here is throwing up an error?

I have a linux Fedora -16 machine that has two interfaces - em1 Link encap:Ethernet HWaddr B8:CA:3A:89:EE:F1 inet addr:136.170.195.17 Bcast:136.170.195.255 Mask:255.255.252.0 ...
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0answers
10 views

dhclient server-addr option supported by linux 2.6?

I've been trying to use dhclient option server-addr (-s) against a Linux 2.6 dhcpd From the dhclient man page: -s server-addr Specify the server IP address or fully qualified domain name to use ...
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2answers
51 views

how to force linux to accept packet with loopback ip

i have an embedded system with an Ethernet interface that needs to accept external packets with IP of 127.x.x.xx. is there a way to force Linux to accept external packets with this loop back address ...
0
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1answer
47 views

Expose internal LAN to VPN using CentOS FirewallD

I have a (tinc) VPN setup with multiple clients that connect to a VPN server that sits on a LAN behind a firewall. I want to expose that LAN to the VPN that server is serving. I've seen a few examples ...
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0answers
63 views

How to set ethernet devices to specific hardware on Centos 7

I have a Centos 7 system where I've disabled the new network naming system and reverted to the old system (eth0, eth1, etc.). I've done this because I'm using this in an RDO Openstack setup, and this ...
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1answer
853 views

Infiniband port status UP but can't open UMAD port ((null):0)

My system has 2 infiniband devices, one of which has both the ports up. $> ibstatus Infiniband device 'mlx4_0' port 1 status: default gid: fe80:0000:0000:0000:0002:c903:000f:0a9f ...
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0answers
74 views

How to add additional network segment?

Long-standing network (A) is as follows Network A: 192.168.37.0/24 GatewayA: 192.168.37.1/255.255.255.0 (eth1) ADSL on ppp0 (via eth0) Kernel IP routing table Destination Gateway Genmask ...