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
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Stop China from connecting to my google cloud compute server

My company has a Google Cloud Compute server hosted in North America. We get so many Chinese IPs sending requests to port 11 that it is costing us money for the ingress. Our firewall blocks all ...
6
votes
1answer
58 views

Is it possible to process millions of datagrams per second with Windows, using a vendor agnostic API?

I am investigating if I can implement an HPC app in Windows that receives small UDP multicast datagrams (mostly 100-400 Bytes) at a high rate, using a dozen or up to maybe 200 multicast groups (i.e. ...
1
vote
1answer
20 views

Routing issue on Linux with Mobile Broadband

Note: This is a "cross-post", I asked this same question on "superuser" StackExchange site, but without obtain any answers, just a comment (now curiously disappeared). I've thought this site is ...
5
votes
0answers
25 views

SynProxy can not return syn ack packets with asymmetric dual bridge topology

I have a asymmetric dual bridge topology as shown below when i connect from 172.16.11.5 and 172.16.10.6 with ssh but i can not connect because of SynProxy. ------- ...
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0answers
10 views

Iptables drop forwarded traffic destined for interface IP address

I have a small VPN setup where I use IP tables to nat traffic coming in the vpn0 interface to the IP address of the eth0 interface. These rules look like this: iptables -t nat -A POSTROUTING -o eth0 ...
0
votes
1answer
11 views

How do i keep ISC-DHCPD from offering different IPs when there is two requests from the same MAC

I have a set of Nodes which get their addresses from ISC-DHCPD. Since they boot using PXE, there will be two rounds of DHCP (one from the PXE, one from the OS) and for some reason, ISC-DHCPD will ...
0
votes
0answers
17 views

Need all local traffic through Debian - Routing? [migrated]

Been dealing with this for some hours now and my head are really spinning. So I got this cable network router (192.168.0.1) that Im trying to pass all my local traffic to. But I cannot for the life ...
1
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0answers
23 views

Mounting encrypted Samba share (linux server/client)

I'm trying to set up encrypted samba access. In order to achieve that I've added 2 lines to [global] scope in smb.conf: server signing = mandatory smb encrypt = mandatory But unfortunately I can't ...
0
votes
1answer
60 views

Starting to learn about IPtables, why do I need this rule?

I have been reading all day about IP tables, how the rules work, sets of rules for basic webservers, etc. Now I`m trying to configure my webserver with IPtables using this thread as a starting point: ...
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0answers
26 views

Linux traffic control input interface using more than 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 nat -A POSTROUTING -o eth0 -s 10.1.1.2 -j ...
0
votes
2answers
51 views

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 ...
-1
votes
2answers
25 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 ...
0
votes
1answer
39 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 ...
-2
votes
1answer
24 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 ...
0
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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 ...
0
votes
1answer
28 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 ...
-1
votes
0answers
24 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 ...
0
votes
1answer
41 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 ...
1
vote
0answers
46 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 ...
1
vote
2answers
61 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 ...
0
votes
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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votes
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 ...
0
votes
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 ...
5
votes
4answers
759 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. ...
0
votes
1answer
73 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 ...
0
votes
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 ...
1
vote
1answer
179 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 ...
0
votes
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 ...
0
votes
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 ...
0
votes
0answers
41 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 ...
0
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0answers
33 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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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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votes
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 ...
-1
votes
1answer
33 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 ...
-1
votes
1answer
63 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 ...
3
votes
3answers
166 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 ...
1
vote
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 ...
0
votes
2answers
34 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 ...
0
votes
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 ...
-1
votes
1answer
58 views

Cannot Access remote CentOS machine using VNC

I am trying to connect to a remote CentOs machine through VNC to get a graphical display. I have followed the steps mentioned in https://www.howtoforge.com/vnc-server-installation-centos-6.5 to ...
0
votes
2answers
90 views

Linux Red-hat 6 Network manger interface priority

I have a question regarding RedHat 6 Enterprise Network Manager (NM): My Linux is connected to two network interfaces. 1 – eth0: Normal Ethernet which is connected to the company LAN 2 – eth1: An ...
0
votes
0answers
23 views

Ubuntu DHCP-RELAY Error

I have a Ubuntu 14.04 server running as a router (4 NICs with IP forwarding turned on). The routing/forwarding component is working fine. However, I now wish to implement a DHCP-Relay/IP helper so I ...
0
votes
0answers
19 views

iptables, after specifying an interface to drop traffic it drops all traffic of all interfaces

We have currently the situation that one interface (eth0) is linked to the internet. and we 2 other devices (eth1/eth2) for management purposes. Now the idea is to block off eth0 completely from the ...
2
votes
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 ...
0
votes
1answer
53 views

Adding a VLAN to Multiple Aliased (Virtual) Interfaces

I have a server running centOS 4.6 with 4 NIC ports. I successfully set up 2 ports with 32 virtual interfaces to handle my VLAN-untagged connections and have no issues with that side of things. ...
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votes
4answers
71 views

Linux-Networking: How do I get routing to work with two network interfaces on the same subnet? [closed]

I have a Ubuntu machine with ip_forwarding enabled. iptables forwards too. I have 3 network cards. eth0 - internet eth1 - client1 eth2 - client2 I want eth1 and eth2 to be on the same subnet, ...
0
votes
1answer
58 views

how to change the ftp passive mode ip address for haproxy work as reserve proxy?

I have an ftp server in LAN, address is 192.168.1.11 I used haproxy is because lots of other service need it I put haproxy on my 192.168.1.1 the same machine of our soft-route(ubuntu 14.04) My ...
0
votes
1answer
47 views

Why is port 443 (but not port 80) being exposed to nmap when iptables is configured to drop the traffic?

A Debian box is running web services on ports 80 and 443 and iptables is configured to allow web traffic only from white listed ip addresses. A second Debian box (that is not white listed) is using ...
0
votes
1answer
51 views

IP Forwarding Issue

This is my first post, so thanks in advance for y'all's help. I'll try to keep the background succinct and relevant. I am running a server on centOS 4.6 for network client testing. I have the local ...
0
votes
0answers
60 views

How to deploy single OpenVPN server instance with multiple unique “--config server*.conf” profiles?

How to deploy Single OpenVPN server instance with Multiple unique --config server*.conf profiles as service start|restart parameter ? Would you please share any tips to run one single Openvpn server ...