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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Can iptables automatically drop established session after certain seconds?

Can iptables drop automatically an established output session after certain seconds e.g. 30 sec. since its launch? But I want to restrict it only for destination port 80 and 443. The purpose is to ...
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0answers
5 views

Linux traffic control input interface using more yhan output interface

this thing is driving me crazy for days now simple nat router using `iptables masquerade and simple linux tc using htb here are the commands iptables -t mangle -A POSTROUTING -o eth0 -s 10.1.1.2 -j ...
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1answer
23 views

docker0 bridge status toggles between enabled/disabled, what could be causing that?

I have some CoreOS bare metal instances that are displaying unusual behaviour on the docker0 bridge device. On one of the instances where this has been occurring, I'm running couchbase server and it ...
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1answer
982 views

Network aliases on boot on Fedora 17

We have a fedora server(Fedora release 17 (Beefy Miracle)) with a few aliases on the main NIC that don't get setup during boot. Here's my config: # cat /etc/sysconfig/network-scripts/ifcfg-em1* ...
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2answers
20 views

Creating Virtual Proxy Server

I know this is not this kind of forum, but I can't find anything in google that really answers my question. Is there possible to create a Proxy server running in a Virtual Machine using only 1 ...
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0answers
16 views

Networking Linux kernel [on hold]

I m writing a code where a packet is dev_queue_xmit(). Just before xmit, I want to know whenever my interface is down. I don't want to add any event driven function for this to make my kernel code cpu ...
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1answer
35 views

dual-homed Centos 7 cannot be ping'd or ssh'd from some on LAN, sees ssh connection refused on one subnet

I have 2 subnets, A and B and a router connected to both A and B and the WAN. I have 4 servers dual homed on subnets A and B, 2 of them are Mac OS and 2 of them are Centos 7 (1503). They are all ...
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1answer
23 views

port forward in INPUT level

I want to change the destination port of the ipv6 packet in the INPUT level. So I tried to use ip6tables with nat in the INPUT level but seems this command does not work # ip6tables -t nat -I INPUT ...
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1answer
970 views

How to stop a infinite running process(ztail) started by a ssh session after that session is closed

I have a peculiar problem. My server supports multiple ssh session simultaneously, so that multiple admins can manage it simultaneously. We have a command which calls ztail to show the compressed log ...
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0answers
16 views

home network bridge + access point [migrated]

I want to create a wired bridge to a wifi setup a firewall + intrusion detection and then setup a wifi-access point for lan-out I currently have a d-link 1200 extender setup as bridge, my desktop ...
3
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1answer
596 views

Limiting bandwidth with hashlimit (e.g. kb/s — not connections!) doesn't work, though the man page says it should

According to the iptables-extensions man page hashlimit can do bandwidth limiting: "flows exceeding 512kbyte/s" => --hashlimit-mode srcip,dstip,srcport,dstport --hashlimit-above 512kb/s ...
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0answers
43 views

Multicast works only in promiscuous mode

I'm trying to receive MPEG-TS over UDP multicast transport in Arch Linux. So when I run ffprobe -i udp://@224.1.1.240:6000 it hangs forever with no result. Then I run tcpdump and it shows no ...
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2answers
957 views

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
13 views

Upgrading Web Application's Systems' Kernels for IW10 & other related improvements - upgrade all machines? LB first? Most important?

Stackers - We're making the push to upgrade the systems for our web app to take advantage of the various TCP improvements becoming more readily available (e.g. ...
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1answer
25 views

AutoFS mount multiple CIFS Shares to same directory

As long as I had only one mount everything was fine. file: /etc/auto.master /mnt /etc/auto.srv1_share1 file: /etc/auto.srv1_share1 sh1 -fstype=cifs,rw,user=jdoe,domain=srv1,noexec,password=xxx ...
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1answer
155 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 ...
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0answers
21 views

What's the best way to create a captive portal access point if my authentication is on a website?

I have my access point set up with dnsmasq and hostapd. Hostapd supports authentication but it is local authentication. I need the user to be limited to a specific login URL, where once they hit the ...
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2answers
160 views

Can't communicate with SMTP server from particular machine

Here is the situation: When I run the following on my local machine, the mail server responds: $ telnet mail.server.com 2525 Trying <mail.server.com IP>... Connected to mail.server.com. ...
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2answers
60 views

Port 22 is accepting connections, but not visible in netstat, unhide etc

So I have this weird issue where one of my boxes is accepting connection on the ssh port (22) even after sshd is stopped. I tried to identify the listening process by the typical means sudo netstat ...
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0answers
44 views

IP-rules don't seem to be working on CentOS-6.6

I faced a bit odd difficulty with policy-based routing on CentOS-6.6 server. I have a setup where I need to enroute all packets originated from 172.25.0.0/16 destinated to 172.24.0.0/16 and some ...
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3answers
3k 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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5answers
11k 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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1answer
1k 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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votes
3answers
163 views

Iptables rules with ! character

I have entered iptables rules to log a specific connection on our server, but it doesn't seem to be working as I want it to. Here are the rules: 1 LOG tcp -- !10.51.0.0/16 ...
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0answers
33 views

Is there a way to write the ip-address of an interface to a file when it comes up? [migrated]

I'm looking for a way to trigger writing the IP address of a host to the file /etc/environment once the networking is up. Right now, all my IP's are static. I'd like in future for them to be DHCP as ...
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1answer
973 views

Kali SYN Flood (Metasploit), not denying service

I have a server with apache2 installed. I tried to do a dos attack on the server by using kali linux syn flood attack, but i am still able to access the website on the server. msf auxiliary(synflood) ...
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1answer
24 views

Running OpenVPN on Xen node causes guest VM to view all inbound connections as originating from the node IP

I have two node servers running Xen 4.2 -- I'll call them Node A and Node B. Node A is running OpenVPN as the server. Node B is running OpenVPN as the client. Both nodes host a number of Xen guest ...
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1answer
163 views

Update version of network manager

In shell on sever I see following error after launching several commands: Error: nmcli (1.0.0) and NetworkManager (0.9.9.1) versions don't match. Force execution using --nocheck, but the results are ...
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1answer
1k 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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4answers
754 views

Transfer large amount of small files

I've to do a migration of two servers with large SAN attachments to our new VMWare environment. EDIT: I have to supply some additional intelligence as I have good answers regarding VMWare solution. ...
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1answer
65 views

Route traffic through private IP for only certain hosts - CentOS 6.6

I am having a weird problem which I cant figure out - so I was hoping someone here could give me a hand. First off the end goal is that a specific server in my network runs an IPSEC connection to ...
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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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0answers
25 views

SNMP agent configuration windows/linux [migrated]

i need to retrieve information via snmp and then use this information to create some sort of graphic application in Unity. I find the SnmpSharp library http://www.snmpsharpnet.com/ i create a little ...
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1answer
1k 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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1answer
24 views

Allowing all ports from an IP

I have successfully entered the following command to iptables sudo iptables -I INPUT -p tcp --dport 5000:5020 -j ACCEPT -m comment --comment "Allow Ports 5000s" However, AFAIK this allows access to ...
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0answers
40 views

KVM port-forwarding from ppp0 to VM's bridged NIC not working, but to VM's NAT NIC works?

I've spent a lot of time on this freaky problem, I've created a simple host and VM configuration to try isolate the problem. Terminology in this question Host: The bare metal server VM: The KVM ...
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0answers
21 views

How to automatically remount iscsi drive, after network errors on Vmware + FreeNAS

Is it possible to force Ubuntu to remount, rescan storage in time manner, to automatically mount it in rw mode? I have a Ubuntu virtual machine on VMware server. And have physical FreeNAS server ...
7
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1answer
10k views

How to troubleshoot latency between 2 linux hosts

The latency between 2 linux hosts is about .23ms. They are connected by one switch. Ping & Wireshark confirm the latency number. But, i dont have any visibility into what is causing this latency. ...
2
votes
1answer
1k views

bridge traffic limiting via tc

I have a Linux machine running as a bridge simulating various network conditions. I use tc for this. Introducing delays or packet loss is quite simple but I got into trouble trying to configure ...
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0answers
27 views

How can i configure a static ipv6-prefix to one linux host [duplicate]

I have a virtual Linux server (Kubuntu 14.04) and i will ask the hosting provider for a complete /64-Prefix for this machine (at the moment i have 4 individual IPv6-Addresses). How do i configure the ...
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0answers
31 views

How to setup 2 switch with VLAN and 2 IPs for each in different block

Below I have depicted the required network. In this network: Lets say GW1 is in IP1 block and GW2 is in IP2 block. There are 2 Linux running PCs with 4 NICs. 1st Linux PC is connected to 2 GWs with ...
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votes
1answer
59 views

Debian - Routing multiple virtual interfaces

I've a Debian computer with multiple external IPs (7 in total), each IP has its own virtual interface (eth0:1,eth0:2, etc...) I would like to know: how can I configure routing so each time I ssh to a ...
2
votes
1answer
1k 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 ...
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1answer
30 views

Cater to multiple countries? [closed]

I run a game server off a linux machine with a single IP address masked by a proxy. The box is located in an LA datacenter, and for players in some other countries, they experience a high ping ...
2
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1answer
31 views

Virtual interfaces with different MAC addresses

I try to figure out how to set up two logical network interfaces (at one physical interface) with separate MAC addresses on a Linux machine. My first attempt was to use macvlan which seemed to work ...
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votes
1answer
32 views

Why must the IP be configured on the bridge device? [closed]

My understanding of a network bridge is having a kind of "virtual switch" which virtually connects the network devices (that were added to the bridge) as if I would connect them to a real switch with ...
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2answers
52 views

Http Requests: how to identify a machine using multiple IP addresses

I have an http server. Is it possible to identify a machine, which is making http requests to my http server using different IP addresses? In other words, is it possible to identify a machine, by ...
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0answers
25 views

Routing private IPv4 addresses internally

I have the following set-up involving two KVM hosts and numerous virtual machine guests on each. The guests communicate to each other on both hosts via [192.168.216.0/24]. [192.168.216.42] is ...
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2answers
33 views

arp table entry outside configured network

Can someone tell me why do I have arp table entry outside interface network? Server has 2 interfaces, both on the same network: eth0 10.10.34.146/22 eth1 10.10.33.188/22 ip route default via ...
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3answers
80 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 ...