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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2answers
39 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? ...
0
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0answers
70 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 ...
1
vote
1answer
276 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
52 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
31 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
votes
1answer
45 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 ...
2
votes
4answers
236 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
31 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
85 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): # ...
1
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3answers
63 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 ...
0
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1answer
669 views

“Stale NFS file handle” after reboot

On the server node, it is possible to access an exported folder. However, after reboots (both server and client), the folder is no longer accessible from the clients. On server # ls /data Folder1 ...
0
votes
1answer
53 views

How can I bridge a VM to a remote network?

I have a system running QEMU/KVM (via libvirt). One of its VMs needs to have a presence on a subnet that is not local to the VM host. I have a Linux system on the remote subnet. Is there a way to ...
1
vote
1answer
346 views

Ubuntu 14.04 LTE forward port to another port

I am looking for a way to forward 1 port to another internally. I have an Ubuntu 14.04 server on which I installed a game server that listens on port 25565. The game does not support multiple ports. ...
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votes
1answer
46 views

How many data packets does it take to log in to facebook? [closed]

I want to find out how many packets are sent when visiting a site on the web. What's a good program that would help me get this kind of data?
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votes
1answer
246 views

iptables destination ip and port

I am looking for a way to forward all traffic(to any port) from a pc to a certain ip. Looking at the rule below : iptables -t nat -A PREROUTING -p tcp --dport 443 --jump DNAT --to-destination ...
1
vote
0answers
29 views

Chef - handle resources changing the network interface

I'm using chef to deploy an openvpn application in bridging mode to an ubuntu node. In my recipe i'm using a bash resource to create the bridge necessary for the vpn to work. Unfortunately the bridge ...
2
votes
1answer
509 views

e1000e Reset adapter unexpectedly / Detected Hardware Unit Hang

I have a Dell 1U Server with Intel(R) Xeon(R) CPU L5420 @ 2.50GHz, 8 cores running Ubuntu Server Kernel Version 3.13.0-32-generic on x86_64. It has dual 1000baseT networking cards. I have it set up to ...
0
votes
0answers
26 views

SYN-ACK with identical MACs

What could cause a CentOS machine to respond with SYN-ACK packet having both source and destination MACs set to the address of the NIC from which the packet is being sent?
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0answers
35 views

Routing, OpenVPN and blocked Packets to Router

I have a running Zentyal Router. Now I have created a Softether-VPN (which wraps OpenVPN basically), to connect to this network per Network-Bridge/L2-Switch. So, when I connect per VPN I am in the ...
0
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0answers
31 views

getting rid of unused listening ports (kernel)

As a follow-up on this question, I have that issue (ports that are reported listening in netstat, but have no process linked to it) and it's the nlockmgr that's actually using these ports according to ...
1
vote
1answer
54 views

Poor performance executing “cp -al” over a NFS export

I am in the process of implementing a backup of a WD My Book Live Duo. This device is configured with software RAID0. The backup source directory is the root of the device, and the destination is a ...
0
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0answers
58 views

Use Cisco VPN connection of another Computer using linux iptables and routing

I have the following need. I have a system that is connected to production environment using a cisco VPN client. At any point of time only one connection is possible. Right now I ssh to that PC and ...
1
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2answers
246 views

No external network access to virtualbox CentOS6.5

I have CentOS 6.5 running locally in virtualbox. I set it up and everything was working perfectly. I came back after the weekend and I noticed the computer was frozen so I had to do a hard restart. ...
2
votes
1answer
179 views

Linux bridging for KVM

I have a Debian Wheezy machine on which I tried to setup KVM with bridged networking. Unfortunately, the bridge does not appear to forward traffic correctly. My setup is the following: The physical ...
0
votes
1answer
71 views

SSH connection timing out on certain clients only

I have a server that has around 100 SSH tunnel connections active from client servers across Canada and the US. We use the same device that runs a custom build of Ubuntu and load that on each client ...
0
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2answers
41 views

Can I configure a connection a network with a gateway with a static ip to a network where the gateway address is assigned via dhcp?

I have two networks with each gateway on a separate network device on a single computer. One is a static ip network on the ethernet device, the other is a wifi connection to a router that is assigning ...
1
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0answers
28 views

IPSEC on linux with multiple remote ISP

I have configured 2 ipsec VPN connection from my linux server to my clients locations. the reason being the client has two ISPs a primary and a secondary on. The client wants to switch to secondary ...
0
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0answers
25 views

Weird tty behavior

When connecting to a group of servers in office, I sometimes get the following weird behavior: For any character I type, the previous character that was typed is displayed. So if I type "Hello" I ...
0
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0answers
144 views

All EC2 outbound traffic is blocked

This is access from WITHIN an EC2 outbound to anywhere. (EC2-BAD) I can get INTO the instance via ssh and I can run my webserver on port 80 and I can ping from another EC2 (EC2-GOOD) in the same VPC. ...
0
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3answers
73 views

locking up a linux box on a foreign network

I have an app that runs on a Linux server and is accessed via each user's web browser. My app contains proprietary code that I need to keep secure. I want to install the app in a client's private ...
3
votes
2answers
115 views

same subnet,different VLAN in Virtual machine

I have 2 VLAN,VLAN 100 and 101 but only one subnet i am trying to make this work with virtual machine so that VM will have two IP address in same subnet but will actually be in two VLAN. steps ...
0
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0answers
71 views

zeroshell unsupported onboard Intel Ethernet I217-V and I210

I recently installed zeroshell 3.0.0 on a machine with a supermicro motherboard that has 2 onboard ethernet cards. It seems that this version of ZS does not support both of ethernet. I've read from ...
1
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1answer
30 views

Can I use --duplicate-cn option for a specific VPN account instead of using at server level?

If I use --duplicate-cn I am seeing it taking effect over all the accounts of my server. I want to make it per client basis, so that I can give this option only to select accounts. Is it possible?
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0answers
96 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 ...
0
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0answers
22 views

TOS reflect on pppoe tunnel in Linux?

How to perform TOS reflect in Linux? In this case, on a pppoe tunnel through eth0, reflect TOS from each pppoe packet onto the actual ethernet packet going thru eth0. On some nicer routers it's a ...
0
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1answer
78 views

Clients losing stateless ipv6 addresses

I'm having problems with Linux VM's at a certain VPS hoster. Periodically the hosts lose their ipv6 address. They go to 'deprecated' and then disappear completely. On the client side I have checked ...
0
votes
1answer
21 views

VPN Connection pooling?

I'm having a problem on PFSense https://forum.pfsense.org/index.php?topic=23914.0 where I can only connect one client with a PPTP VPN to a VPN Server outside out network. PFsense is our firewall and ...
1
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0answers
14 views

Windows network failing, not present on linux clients

got a really strange one for you all. I have a network setup using a linux machine as a gateway between various network segments (on seperate nic's) and virtual machines (one of which is a mail ...
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votes
5answers
75 views

How do i down the server on the remote location for an hour

This is the doubt i have in my mind we can reboot the remote server using reboot command but how can we down the server for an hour or a specific time. In our case we login to the server through putty ...
0
votes
0answers
165 views

Open vSwitch double VLAN tagging is ignored

I'm trying to add a flow to a KVM machine using Open vSwitch 1.10.2 for it's networking, which double tag all traffic comming from one of the virtual machine's ports. I'm using the following command ...
0
votes
1answer
82 views

Ubuntu server - NIC suddenly loses connectivity

I'm scratching my head. I recently configured a server with two identical Intel NICs inside a DMZ. This morning at around 8:05, I successfully SSH'd in through the internal interface (via my LAN-based ...
1
vote
1answer
80 views

ssh connection freeze after password phase

I'm trying to connect to a server (Oracle Linux 6.3) and after I insert the password the session just freeze. I checked the audit log and I've authenticated successfully, after I restarted the ...
0
votes
2answers
71 views

Can I limit my autoSSH Tunneling Speed with trickle and ssh config file option?

When I use only ~$ autossh site1 it work perfectly, but whit trickle the pameter site1 is considered as DNS Name instead of conf block. User@VM:~$ sudo trickle -d 10 -u 10 -- autossh site1 [sudo] ...
0
votes
1answer
65 views

autostart ppp connection when vlan comes up

I want to start a ppp connection on my router on startup, but i need to have a vlan activated before. The problem is that if i ifup the vlan in the ppp interface, the vlan is not up when pppoe tries ...
-1
votes
1answer
92 views

Designing a secure network layout

Over the last few years I've accumulated a lot of hardware that all currently exists on a flat network. There are a number of devices: my desktop, laptop, and computers of the rest of the people I ...
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votes
4answers
226 views

Is there anyway to tell what user will receive data from inbound packet?

In linux, considering this use case: 1. User initiates http request for webpage to remote server 2. Remote server answers request and sends packets Is there any reference to the user who started ...
0
votes
1answer
84 views

storage traffic not going through Bonded interface

hi few days back i have asked a question here choosing network interface based on network purpose on my Centos server there are 4 NICs i bonded first two NICs and created bond0 with an MTU of 8600 ...
0
votes
1answer
97 views

squid3 with tcp_outgoing_address could not connect to anywhere

I have one server with 3 interfaces (3 physical lan card), which are connected to 3 different routers. Each router has a different subnet, i.e. the 3 interfaces of server belong to 3 different ...
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votes
1answer
145 views

PPTP and windows 7 809 error [closed]

I want to connect from home to my router(linux mashine) at work. i have installed pptpd. i have added following fw rules: iptables -I INPUT -p tcp --dport -j ACCEPT iptables -I INPUT -p gre -j ...
0
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0answers
89 views

Linux routing: How to allow a device inside private network to connect a public IP over an unknown network?

Consider following network topology: ---------- ---- (my network) ---- | Device 1 | (.101) | 192.168.191.0/24 | ---------- | | ...