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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1answer
23 views

Change default gateway on Linux [on hold]

I can change the gateway for a particular IP with sudo ip route add x.x.x.x via y.y.y.y but if I do the same with all IPs with sudo ip route change 0.0.0.0/0 via y.y.y.y then I lose the connection ...
1
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1answer
17 views

Proxmox: 1 NIC, 1 Public IP, unable to get WAN interface working in VMs

I have a computer running Proxmox, and it has 1 single NIC that is directly connected to internet and has a single public IP. Then, I have different VMs (KVM) running and one of them is pfSense. What ...
1
vote
1answer
26 views

1-dhcp server for 2 separate network

Debian Server Setup (wheezy) 1 - eth0 - Connected to INTERNET 1 - eth1 - LAN 1 (Network 1 : 192.168.100.0/24) 1 - wlan0 - Access Point (Network 2 : 192.168.200.0/24) /etc/network/interfaces auto ...
0
votes
2answers
12 views

Make some route info persistent on RHEL

I would like to make the following route info persistent. I know how to do it for the default, but how about this line: 10.27.74.0 * 255.255.255.0 U 0 0 0 eth0 ...
1
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0answers
12 views

Process-wide VPN connection via openconnect

I'm using openconnect to connect to a remote endpoint and SSH onto the machine inside the remote network. The problem is, when I do create the connection, the machine I do it on is unresponsive for ...
1
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0answers
18 views

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
13 views

Openswan tunnel established; but have access problems

I am working on connecting two office using OpenSwan IPsec VPN. I have successfully established the tunnel, but ran into strange problems: Let's say subnetA(192.168.1.x/24) and ...
0
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0answers
14 views

Route 2 external IP ranges using pfSense

I have pfSense running on some hardware routing my /27 block of IP addresses assigned by my ISP. I asked for and got another /26 block that I want to send all of the block to a single server (it will ...
5
votes
1answer
170 views

Nagios alert based on scheduled MySQL queries results

I have installed Nagios 4.0 on my Ubuntu 14.0 and i want a plugin to alert me based on daily scheduled MySql queries .. if the result of ( select count(*) from tableName > 10 ) raise a critical ...
0
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1answer
29 views

zabbix network interface app shows no items for CentOS VM

I'm using a Ubuntu VM as Zabbix server and Zabbix agent1, and a CentOS VM as Zabbix agent 2. And when I look at the overview at the property "Incoming network traffic on eth0", only Zabbix agent1 (the ...
0
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0answers
9 views

source based routing policy use ip route not works on my vm

I have an vm created with vmware. an installed centos 7 as os. the kernel is 3.x. now , my system have to network interface. and I want connect them to the same network. forexample : ...
1
vote
1answer
47 views

How would traffic be routed with this routing table

I ran across two entries in a linux routing table that both have the same destination, but have different gateways. How would this traffic be routed? I've been searching around online for additional ...
0
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0answers
24 views

Purpose of sysctrl tcp timeout unack field

Could some one let me know the purpose of sysctrl tcp timeout unack? If i modify this value from 300 t0 400, what will be the impact. /proc/sys/net/netfilter/nf_conntrack_tcp_timeout_unacknowledged ...
1
vote
0answers
17 views

dhcp relay with failover to local service

I'd like to set up a dhcp server which normally relays to a central site, but has a pool of addresses to hand out if the link to the central site goes down. I'm using isc dhcp server on Debian, but ...
0
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0answers
38 views

configure a dhcp server to serve two different scope on the same subnet with multiple interfaces

Ok, so here I am with a pretty complicated problem on a Debian Wheezy server I have three interfaces : eth0, eth1 and wlan0 on a single server, eth0 will act as a gateway for eth1 and wlan0, I have a ...
0
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1answer
20 views

what could cause a not so busy redis server to close connection?

We have 17k tcp connection in CLOSING state on redis server. My understanding is that only client would initiate closing a connection, not from a redis server. So I should see 0 connection in CLOSING ...
0
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0answers
27 views

Trying to create a NAT with virtual Ethernet using IPTables

I have a separate namespace running on my server and I want to create a NAT that will enable Internet connectivity in this namespace. I specifically want to do this so that certain inbound ports are ...
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0answers
19 views

IPTables Quota Limiting and Redirect

I am currently working on a quota limitation for a wireless captive portal based on iptables. With the following ruleset all new connections get redirected to the login page after the quota is ...
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2answers
58 views

How are packets routed from my VirtualBox Virtual Machine to my local host OS environment? [closed]

I have a basic question I do not understand regarding the IP given to a Virtual Machine running on my laptop. I use boot2docker (basically, it creates a VirtualBox Virtual Machine to have access to ...
0
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3answers
34 views

“Bad argument 'NEW'” when configuring iptables

I am getting the following error when configuring iptables on a Debian 7.6 server to log new TCP connections: Bad argument `NEW' Error occurred at line: ## The line throwing the error is formatted ...
0
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2answers
33 views

Excluding some network services from VPN

My local linux server is connected to the internet via router. Router (192.168.0.1) does NAT from ISP assigned IP address (which changes from time to time) to server's local IP (192.168.0.102). When ...
0
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0answers
3 views

Bridging multiple networks with a tinc vpn in virtualbox, won't forward packets properly [migrated]

I set up a network with some VMs in VirtualBox. It consists of: 1. The host, OS X. It is connected to the Arch VM described in 3. via a host-only adapter. OS X has the IP 172.31.2.100/16. 2. ...
0
votes
1answer
62 views

I cannot connect to OpenSSH server running on Ubuntu server from Git bash running Windows, through Cyberoam firewall in network

Situation: I am trying to connect from OpenSSH client inbuilt with Git Bash running on Windows 7 professional x64 to OpenSSH server that runs on Ubuntu Server LTS 14 x64. Both of which are over the ...
0
votes
1answer
19 views

Assigning a public IP to a Xen Guest machine

On my CentOS server (dom0) I have 4 Ip addresses: eth1 - 56.x.x.100 eth1:1 - 56.x.x.101 eth1:2 - 56.x.x.102 eth1:3 - 56.x.x.103 How can I map eth1:1 (etc) to one of my guest machine? Currently ...
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0answers
14 views

Bridging Interfaces and limiting Egress of children

HISTORY: First let me explain what I want to do: I want to setup a development / staging environment based on LXC so our developers can rapidly deploy and tear down VMs. We have a single public ...
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0answers
24 views

how to change MTU inside docker container which is running with ubuntu 14.04 and also on host machine with ubuntu 14.04?

I want to change MTU(Maximum Transmission Unit) inside docker which is running on ubuntu 14.04. also docker container running with ubuntu 14.04. The problem is that its docker0 interface on host os ...
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0answers
26 views

Tomcat 7 inaccessible on digital ocean

So, I'm trying to get Tomcat to work on Digital Ocean. The server starts up without errors, but it's inaccessible both locally and remotely. It hangs when I try to access it. However, it does work ...
3
votes
1answer
26 views

Please clarify for me how tcpwrappers works

We've recently gone through a security audit and among several valid and other, quite pointless findings is one that states that tcpwrappers is not disabled. I've never used tcpwrappers so I don't ...
0
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0answers
11 views

What part of the reboot cycle in Linux is WinSCP detecting as FTP port 21 being available?

When I rebooted one of my boxes running Ubuntu Server LTS 14.04.1 today, I received a strange message from WinSCP during the automated reconnect attempt that I've never seen before: ...
1
vote
1answer
47 views

How to make a simple script that increases a number character by 1

I have to add a single command for MANY vlans, and wondering if I can generate a simple text file somehow? Then I can simply paste the text file into the network switch and it will add the needed ...
0
votes
1answer
40 views

Why are eno1 and eno2 in this order?

I've just installed a Fedora 21 Workstation system, and it's reversed the order of eno1 and eno2 from the CentOS 6 system that was on here before. lspci | grep Eth 00:19.0 Ethernet controller: Intel ...
0
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0answers
7 views

what is the value for setting a hostname in installation of oracle enterprise linux r6u5 should have? [migrated]

I am installing oracle linux r6u5 for my personal use in vmware workstation. While going through installatio i came to a point where I have to enter hostname, format specified init is ...
1
vote
2answers
33 views

how to check the number of connections open towards internet from a linux server?

We have issue where the response time from a endpoint is specifically having more response time for one server but not on other server. Further we found that this issue happens for all endpoint which ...
0
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2answers
36 views

Multiple IP addresses on host and one on kvm

I've recently configured my network using advice from this question but now I need to configure this a little different. I'm using Debian distribution. I have one dedicated server with 3 IP addresses ...
0
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1answer
48 views

Networking in Linux KVM

I want to know if there is any way other than using linux bridges to interconnect interfaces from two virtual machines ? Since I am trying to run private spanning tree implementation in virtual ...
0
votes
1answer
23 views

How to duplicate multicast packets on several interfaces?

I would like to send a stream from a Linux server to several Linux clients via a multicast address. The clients are directly connected to the server but on different interfaces: bnep0 and bnep1. ...
0
votes
1answer
31 views

forwarding packet from one interface to another interface

I have an embeded system with 2 interfaces e0 and m0, whose ips are 10.0.0.20 and 192.168.0.20, respectively. Incoming packets into e0 have an ip of 10.0.0.10 and should be forwarded to m0 interface ...
1
vote
0answers
33 views

How to use iptables or IFB to mark incoming traffic by device?

I'm trying to use iptables to mark incoming packets based on the device where those packets arrived (rather than their originating IP address or port etc), but haven't found a way of getting this to ...
0
votes
1answer
90 views

iptables v1.4.21: Couldn't load match `-d':No such file or directory

i am running kerenl 3.14.18 and using iptables 1.4.21, built with these options --static-enable --disable-shared. when i run this command: /sbin/iptables -A PREROUTING -m -d 127.3.0.2/24 -j DNAT ...
0
votes
1answer
29 views

Two IP addresses one network interface and virtualization

I have a Debian [H] host server with one network interface, configured like this (/etc/network/interfaces): auto lo iface lo inet loopback auto eth0 iface eth0 inet static address xxx.yyy.zzz.77 ...
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votes
1answer
38 views

OpenVPN all subnets the same, send a single client to tun0?

The two networks in question are listed here.. The wlan0 is on 10.0.0.23/24. tun0 (openvpn) is on 10.8.0.6 but is routing traffic to the network 10.0/16. So both wlan0, and perhaps tun0 could have ...
1
vote
3answers
78 views

Is it wise to use OpenVPN to connect remote web servers?

I have a number of remote hosted servers for various purposes--web and application servers. I effectively want a "management network" of sorts so I can simplify tasks like log collection and package ...
1
vote
1answer
25 views

How are the routing tables populated on a Debian system?

How are the routing tables populated on a Debian system? I understand that the ip route family of commands can be used to manually manipulate the routing tables, but how are the routing tables ...
0
votes
1answer
46 views

Using a pfSense guest to firewall/route traffic for other guests

I was curious if this falls into the "why..." category or not. I have a dedicated, hardware UTM (Untangle) that's serving as an edge device with two hosts and a dozen guests behind it. Right now, I ...
0
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0answers
53 views

KVM Aggregate Throughput Limited at 1Gb - Virtio Queues Limiting Factor?

I have a KVM host with three NICs and can't get traffic between guests (in same subnet) above 1gbps aggregate. Is this by design and the only way to achieve >1gbps to use multiqueue support? So far, ...
3
votes
1answer
61 views

Linux Server Virtual Ethernet interface stops responding to arp requests

I'm hoping someone has had this issue before as it is driving me nuts. I have 2500 linux embedded Linux servers. We use these servers partly to act as gateways to other devices sat on a private ...
0
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0answers
110 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:~$ ...
2
votes
1answer
67 views

Sending Data extremely slow or RDS

I have the following two profiles for a basic SELECT STATEMENT: select count(*) from mturk_completion; Here are the two profiles: # My Local machine, using a local db Status ...
1
vote
1answer
29 views

Debugging a mysql connection

I am trying to figure out how to diagnose a mysql connection issue. When I run a group of queries locally on my machine it takes about 1s to run. When I run that same group of queries on an AWS ...
0
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0answers
47 views

Enable Netflow plugin in Ntopng

How can I enable the Netflow plugin in the latest Ntopng (1.2.2). There is no 'Plugins' option in the menus or I can't see it. I have logged in the web interface at port 3000 but there is no Plugins ...