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 can I log and maybe even block IPs that send lots of incoming UDP traffic?

we run a voice / teamspeak server which receives legitmate traffic on port 9987 from many ips. Sometimes we get DDoSed. So people use single Servers and send 1-3 Gbits of UDP Floods to that port. This ...
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1answer
61 views

How can I access a Virtual Machine on different subnet? [closed]

I have two virtual machine VMachineA and VMachineB using virtual box. VMachineA (CentOs 6.5) has two network interfaces: eth0 (IP: 192.168.3.48, GW: 192.168.3.1) and eth1 (IP: 10.10.200.1). ...
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1answer
401 views

Proxmox VE: Multiple shared public IPs with NAT configuration

I have a Proxmox VE (v3.3 @ Debian 7 Wheezy) and got 3 public IPs routed to that server. It is my aim to have multiple VMs sharing those IPs using a NAT configuration so that I can forward single ...
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2answers
1k views

Setting up a server with two NICs using two separate subnets (each on a different VLAN)

I'm using Ubuntu 14.04 (standard server install + OpenSSH, biosdevname=0 during instal to keep the network names simple) in an environment where I have two non-overlapping subnets M and N on different ...
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0answers
142 views

IPFire configuration as IDS behind router

I want to use an IPFire-Server primarily as an IDS behind an already existing router. The network's router (192.168.1.1) has access to the Internet and provides LAN-Slots for the clients. There is ...
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0answers
108 views

Load Balancing over multiple ISP connections

I have been trying to implement load balance and fail over on a linux machine having multiple interfaces. Currently I am using two ISP lines and I wish to split the network traffic such that both of ...
2
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0answers
43 views

IPsec - strange behavior

I have set up site-to-site ipsec connection between linux(debian) and mikrotik router. The tunnel is up linux configuration: config setup interfaces=%defaultroute keep_alive=60 ...
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3answers
367 views

Multiple ethernet interfaces

I have a two network cards, configured like this: eth0 Link encap:Ethernet HWaddr 00:19:d1:31:08:e8 inet addr:192.168.5.104 Bcast:192.168.5.255 Mask:255.255.255.0 inet6 ...
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1answer
75 views

how to connect/bridge two interfaces on different processes

I have two processes A and B (simulating real hardware device), each with their own TAP interfaces. If I want to send an ethernet packet to A, I send it on interfaceA, and similarly if I want to send ...
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2answers
242 views

link aggregation with wifi and ethernet on Linux

I have a computer running linux with a wifi and an ethernet interface. I'd like to set up link aggregation (at least fail-over, but other modes would be nice too) between these two so that both this ...
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0answers
190 views

Linux router with multiple gateways and port forwarding

I want to use a Linux VM to act as several routers at once. I have multiple servers hosting different services and dedicated public IP for each of them. Super simplified setup example: Ubuntu ...
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1answer
413 views

Keepalived load balancing MySQL. Backup server time-out

Dear beloved people at ServerFault. I'm trying (and failing) to setup a load balanced MySQL server array. Please enlighten me, show me the error in my ways. Current setup: two MySQL servers with ...
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0answers
82 views

Connectivity issues (slow response) to a remote VM via SSH

I am on a linux machine trying to Ssh into a remote Centos 6.4 server via VPN. The server often gets disconnected and response too is slow. I see the messages on the terminal once in a while: ...
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1answer
252 views

should a virtual interface clash with keepalived?

I was working on a server today, debian squeeze. After testing this on two staging servers, I added a virtual network interface to /etc/network/interfaces like this: # The primary network interface ...
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1answer
29 views

What kinds of configuration can prevent a network interface from seeing traffic?

I have two ethernet adapters on my Debian system, eth0 on my local network statically assigned to 192.168.2.1, and eth1 with a dynamic IP connected to the internet. I know this setup works, because ...
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0answers
76 views

How do I automatically advertise a preferred route via BGP using keepalived?

I have a dual firewall setup with 2 active paths to the internet. These are independent and cannot be linked together on the WAN side. It's part of a deployment at a datacentre. Each firewall has ...
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votes
1answer
92 views

Ubuntu insufficient disk space [closed]

I am getting an insufficient disk space error, here is my df -h Filesystem Size Used Avail Use% Mounted on /dev/sda1 29G 28G 31M 100% / none 4.0K 0 4.0K 0% ...
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0answers
75 views

Printer on OS X not printing across VPN subnets

I have an interesting situation where I have a two servers that connect two subnets via a VPN. One side is 192.168.0.0/24 and the other is 192.168.1.0/24. Communications appear to be working okay. I ...
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1answer
227 views

Limit max bandwidth per IP

I have some partners, that uses one of my linux servers as a gateway. The problem is I need to limit bandwidth per client ip address on this gateway. My partners client ip ranges are not known to me. ...
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0answers
193 views

Dual WAN setup in Redhat/Centos Linux

I want to setup a Linux Server running SIP (freeswitch) applications with 3 NICs as follows: 2 of the NICs are WAN connections and the 3rd is a Private network for routing requests to other hosts on ...
1
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1answer
931 views

Debian up in /etc/network/interfaces not working

I'm trying to add a secondary IPv6 address to eth0 on Debian Sid. I added the following lines to /etc/network/interfaces: iface eth0 inet6 static address [IPv6 address #1] netmask 64 gateway ...
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0answers
170 views

Using my IPs on OVH server via GRE

I can't route my IPs into a OVH server, can you help me to find the problem? Mikrotik GRE IP: 192.168.55.10 OVH Server GRE IP: 192.168.55.20 GRE iface name: ali1_fr1-ovz1 IP to route from Mikrotik to ...
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0answers
69 views

stress testing a QOS switch

I need to test a network Switch that has QOS capabilities. I need to simulate a large network (preferably up to or exceeding 100 devices), and I need to do it as a live test. My requirements are: • ...
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39 views

HA router with keepalived showing unexpected traceroute

I have a couple of routers in HA using keepalived vrrp daemon under linux. Here are the addresses x.x.x.129 floating (keepalive) x.x.x.130 router1 (static) x.x.x.131 router2 (static) Something ...
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2answers
242 views

RSync stalls after 32768 bytes

I have an issue which I am struggling to understand. I have a server which is hosted by a business parter on their network but my team is responsible for installing and configuring software to this ...
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0answers
30 views

Local DHCP to setting up Nimbus cloud networking

I'm currently trying to install the Nimbus cloud in two machines (centOS 6) test environment inside the department/university network. The problem is that I can't install directly a DHCP server and ...
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1answer
249 views

Why Linux guest VMs performs better than Windows ones in terms of network?

I am testing the network performance of VMs in Xen and Hyper-V using Iperf and Netperf. In both hypervisors I found a Linux guest VM in different modes is having a relatively high performance than a ...
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0answers
138 views

Dual homed Linux host (Debian/Ubuntu) using DHCP

We have an Ubuntu server with 2 NICs. Each one is on a different subnet. Besides there's a third subnet. Clients sit on all three subnets. All clients should be able to talk to both server IPs so we ...
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votes
1answer
46 views

What happens when a static IP address is unavailable? [closed]

I have several Raspberry Pis configured with static IP addresses (192.168.1.203 being one of them). I swapped out the router yesterday, and this router is using a different IP scheme (192.168.178.*), ...
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2answers
243 views

Corosync :: Restarting some resources after Lan connectivity issue

I am currently looking into corosync to build a two-node cluster. So, I've got it working fine, and it does what I want to do, which is: Lost connectivity between the two nodes gives the first node ...
0
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1answer
2k views

CentOS 6.5 proxy bypass/no_proxy not working

I am running CentOS 6.5 on my desktop. I've set the Network Proxy using the network proxy application provided under Preferences. I've also set the following exceptions: ...
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2answers
46 views

Open Specific Linux Port

Im trying to open a Port(2012) on my VPS so i can access it over the internet. This is the output of sudo iptables -L produces Chain INPUT (policy ACCEPT) target prot opt source ...
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0answers
48 views

Watchguard XTM 23 blocking company website

The company that I'm working at runs a website and 1 week ago the site started returning 404's whenever anyone tried to access it from our protected network. We immediately checked on the status with ...
0
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1answer
112 views

Linux static dhcp ip for visitor access internet without requesting MAC address? [closed]

Currently, my company internet access for visitor are required to request MAC address from them if they want to access to internet. Can we do something like the Hotel wifi? they just access to the ...
0
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2answers
315 views

how to get ip address of a PPP(Point-to-Point Protocol) network interface?

I have a Linux machine with two network interfaces, and I'd like to get the IP address of the PPP interface w1g1 but it doesn't show up in ifconfig. There is a public IP on the PPP interface, but ...
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1answer
138 views

Linux peer-to-peer ethernet bonding

I have two linux servers. Each have 2 ethernet ports. I connect port-to-port with straight-through ethernet cables between the 2 servers (there is no network switches involved). I want to bond the 2 ...
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1answer
574 views

Adding subnet to a vsphere with single vcenter and esxi host

Let me start of by saying that I do not specialize in networking, I am in the process of adding additional VMs to a testing environment and wanted some recommendations. In this case I am running a ...
7
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2answers
1k views

How can I switch from a custom linux network namespace back to the default one?

With ip netns exec you can execute a command in a custom network namespace - but is there also a way to execute a command in the default namespace? For example, after executing these two commands: ...
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0answers
76 views

Policy routing local user's traffic down a tunnel

I've got a Linux based Firewall/Router running iptables and SNAT for traffic passing through it to the Internet via a single uplink - This is working fine. There is also a small number of applications ...
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2answers
114 views

Siege - running a stress test benchmark

I need to do a benchmark test of a HTTPS server using Siege, to see how it behaves under massive load. I'm initiating tests from another machine which is quite powerful and it is connected to the same ...
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2answers
47 views

Allow connection only from 2 ips [closed]

I need to block all connection on port 30000. I alredy did that , with command like that iptables -I INPUT ! -s IP_HERE -p tcp --dport 30001 -j DROP but now i need 2 ips , how i could do that? ...
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0answers
138 views

What it takes for an openstack instance to connect to internet

I'm running a two node openstack cloud with single NIC using nova-network, Everything seems fine but when it comes to networking there are many problems and I think thats due to having only one NIC on ...
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1answer
2k views

KVM Ubuntu Guest cannot connect to the internet on bridged networking

I have Ubuntu 14.04 (64 bits) + KVM Host with 2 NICs: - eth0 connected to the "public" network - eth1 connected to the br0 bridge with a private ip address range From Host I can access internet, ...
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0answers
204 views

Opening a port range using Open VSwitch

I am locking down a VM on xenserver to allow only port 3389 and the ports required for domain controller authentication on windows. I am trying to do this using Open VSwitch. Locking down and allowing ...
1
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2answers
77 views

When a socket switch to TIME_WAIT state, why I can't see its inode number?

I'm developing a program in python that parses /proc/net/tcp informations, but unfortunately, while I was doing this, I saw a strange thing. Practically, when a socket change in TIME_WAIT state, ...
2
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1answer
89 views

Two LAN cables when using Remote Access Card?

I recently bought a HP MicroServer N54L and a HP Remote Access Card. Connecting to the server over a KVM viewer for BIOS setup etc. works fine, but when it comes to installing Ubuntu 14.04. the ...
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4answers
887 views

/etc/hosts.deny ignored in Ubuntu 14.04

I have Apache2 running on Ubuntu 14.04LTS. To begin securing network access to the machine, I want to start by blocking everything, then make specific allow statements for specific subnets to browse ...
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votes
1answer
48 views

Get dhcp ip from a specific server [closed]

In a network that comes with two dhcp servers, how can I get network configured from one server instead of the other? Let's say there are 2 dhcp servers named A and B. My computer always get network ...
0
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1answer
356 views

How to load new profile in Network manager v0.9 without nm-connection-editor using cli?

i'm working on migration of autoprovisioned Ubuntu 12.04 LTS servers from ifup (/etc/network/interfaces) to NetworkManager. /etc/network/interfaces is clean (only loopback interface is configured): # ...
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3answers
134 views

network usage per user in linux [duplicate]

I am administrator of an openSUSE linux server which is used by many people in our company. Today we find out that yesterday one of the users use too much of bandwidth and its important for management ...