Networking refers to the technologies and techniques that enable the interconnection of devices and applications allowing them to communicate electronically.

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CentOS 6.7 vm static external IP setup issue

I have a new vm setup and have it setup like my CentOS 5.5 vm on OSX. It is a strange setup since we used Comcast Gateway as the router, and I really don't want to change that since we're using Mac, ...
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1answer
124 views

Any tool for forking/teeing/sharing a TCP connection to the remote server? [closed]

Could down voter please post your reason, as it's not obvious to me? Here's my problem. I'm building an automation program that talks to a remote server (think of it as a chat server or MUD game ...
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0answers
20 views

Firewall-Rules on Proxmox-Node cause VPS to be offline

I'm using proxmox to virtualize some small machines based on KVM. To do so I created the following network-config on the KVM-VPS: # This file describes the network interfaces available on your ...
2
votes
1answer
82 views

configure docker network bridge IP for multiple IP alias

I got a Ubuntu host with multiple IP address aliases and I want to expose the ports from docker containers connected to one docker network bridge to a specific IP address of the host and the ports ...
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0answers
16 views

What is the default value for TCP accept queue length on Linux?

I have read this article but it doesn't mention where the default accept queue length can be found (it does mention tcp_max_syn_backlog though, but it's different). I'm working on a Java 8 project ...
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0answers
27 views

Large payload - connection get's Hung with CLOSE_WAIT or LAST_ACK state

We have a webservice client which posts data to a 3rd party Webservice. We are having an issue when the payload is a bit large (Around 600KB) xml. Once we pay the process hangs forever. The Netstat -...
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1answer
63 views

Multiple Gateways for Single Subnet

Right, this might be a long one, so bare with me... I have 2 machines, lets call them local1 and cloud1. local1 has 3 Nics: 2 connected directly to cable modems with public IPS (call them eth0 and ...
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1answer
78 views

proFTPD unable to connect after update ECONNREFUSED

I am working on Debian 8 - ran a series of automated system updates and now I am unable to connect to my local server running proFTPD. I have made no changes to the client attempting to connect to ...
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0answers
18 views

Infinite loop of RST/ACK and ACK

I have web servers (Apache-Tomcat) at IDC to serve https requests from Android and iOS clients. Suddenly I noticed traffic to web servers was dramatically increased (10Mbps to 80Mbps). So I tried to ...
0
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0answers
36 views

LXC containers cannot connect outside of VM

I have two CentOS 7 LXC containers on a RHEL 7.2 VM using virbr0 as a virtual bridge. Originally, container1 could connect out and do e.g. yum installations, but after I created container2, neither ...
2
votes
1answer
60 views

Possible to force TCP window scaling to a higher value?

Is it possible to increase the TCP window scaling factor on Linux (CentOS 7.2)? I have a long fat network (100 Mbps) from London to Chicago and I'm getting 16 Mbps throughput in TCP on an sftp from a ...
3
votes
1answer
87 views

HP ProLiant BL460C Gen9 - NICs

Is there a way to get more than 4 physical NICs (4 active/4 standby) on an HP BL460c Gen9 server WITHOUT using mezzanine cards and extra VCMs? EDIT for more information: I have two c7000 enclosures. ...
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0answers
21 views

Using the host inet address to connect containers

Running an Ubuntu 16.04 server as a docker host. One of the services I start has the following run script. #!/bin/bash # retrieving the inet address INET=`LANG=c ifconfig | grep -B1 "inet addr" | ...
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votes
1answer
56 views

How can I connect a group of vms in Azure?

I have a number of Azure Linux VMs. I am able to ssh into all of them using the public azure connection info, however I am not able to ssh from one vm into another vm using the private info. I have ...
1
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1answer
93 views

Slow file transfer speeds

I have a server that is running Ubuntu Server 14.04LTS and I am currently experiencing slow network transfer speeds. This server had been running without issue now for about 2 years and suddenly I am ...
0
votes
1answer
71 views

libvirt: set hostname using dhcp in virtual network

I've configured a host-only (aka private) network for a group of VMs on a CentOS 7 host. I've created static leases in the DHCP section for the virtual network. The IP address is getting set ...
0
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0answers
96 views

IPv6 not working

I'm unsure as to why this is happening... anyway, let me start from the beginning The Setup 1 * Dedicated server with a /29 IPv4 and /48 IPv6 (from Nocix (DataShack)) 1 * CentOS 7 KVM host 1 * ...
2
votes
1answer
171 views

Tune windows for high latency/high bandwidth tcp transfers

How can I speed up my Windows 7 tcp file transfers over a 100 mbps link between Chicago and London? Right now, I am transferring two 4GB files in two sftp sessions. Each file transfer is running at a ...
1
vote
2answers
61 views

Can't ping between two VMs

I have two VMs that, up until yesterday, have been able to talk to each other just fine. Now they don't. I've been trying to get this fixed for several hours now, but haven't been able to figure ...
0
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0answers
28 views

PPTPD VPN Can't connect to the internet

I'm running a Ubuntu 16.04 Server on a VMWare ESXI Server with its own public IP, I have setup a pptpd vpn server which works but only with connected devices. I can't connect to the internet with it ...
0
votes
1answer
53 views

Network maps, best admin practises and how them saved your ass?

I am reviewing the security of a (quite large) network. There are a some thousands switches, several hundred routers, several hundred access points, tenths of FW, IPS, and so on. PCs and servers are ...
0
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1answer
77 views

How to secure dual-homed Windows Servers that are connected to the internet

We have two machines running windows server 2012. Both have one NIC port connected to the public internet and another NIC port connected to a switch with internal IPs (192.168...). What is the most ...
2
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3answers
54 views

VisualSVN server visible on internet, but not all subcommands work on client

So my boss is a nice guy who's open to trying new ideas, and I talked him into letting me start new projects on svn (instead of an older version control system). At this time, we've realized that it's ...
-2
votes
1answer
44 views

Can I create an Ad-Hoc network between NAT virtual machines and computers/virtual-machines external to host? [closed]

I want to create a network between virtual machines on my laptop which are running Windows Server and other virtual machines in another laptop that will be running Windows Server as well without using ...
1
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1answer
228 views

Huge performance penalty in gbit link with ip forwarding / masquerade through clear VPN tunnel

I have a problem with IP forwarding between my home computer and a remote server (from online.net). My home connection is a 1 Gbit/s FTTH and the remote server has a 2.5 Gbit/s bandwidth. The context ...
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0answers
31 views

Set-up VPN using DD-WRT router

I'm trying to set-up a VPN with a DD-WRT router in a Windows 2012 environment. I followed the steps from DD-WRT wiki 2, but I can't manage a connection. Firmware: DD-WRT v3.0-r28788 std (01/13/16) ...
1
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1answer
66 views

duplex affecting bandwidth test, router--switch--NIC

Netgear FVS336gv3 router, 50x50 dedicated fiber. ISP instructed us to set WAN port speed to 100mbps full duplex; done. Router connected to Netgear GS748T 48-port switch. GS748T port set to "auto" ...
1
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0answers
19 views

GNS3 - Connecting Emulalated IOS to TWO PHYSICAL networks

I have a CISCO c3725 router on GNS3 connected to two different and separate unique LANs via the CLOUD/HOST icon, attaching each of the virtual CISCO c3725 to my computer's physical NIC (NIC 1 and NI2.)...
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0answers
51 views

linux veth use existing peer interface

I have a sit tunnel interface which I want to transparently connect with one end of a veth pair so that everything that drops out of the tunnel interface flows through the veth interface and vice ...
2
votes
3answers
46 views

Override AWS Auto-assign Public IP settings after instance launch

There is a limit to 5 public IP addresses (Elastic IPs) for each AWS Account and I have reached such limit. Now I have many EC2 instances created without the "Auto-assign Public IP" attribute, which ...
0
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0answers
40 views

Ubuntu 16.04 LXD No any communication between guests and master

Welcome. I had a little problem with my LXD server. On my master I have some guests systems (ubuntu 16.04 image), all of them are bridged to master and are in my local subnet at home, and have an ...
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0answers
24 views

Can't reach centos server after “Multicast listener report” IPV6

I ran into a problem that occurs only on a few servers. Every 5-6 minutes I lose connection to the server, and it get backs after a few minutes. In most cases it's a VM that is not reachable while ...
1
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2answers
79 views

Debian / IPv6: Default route expires after 1800 secs, loosing connectivity

I'm running Debian 8 on a vServer. After installing docker and enabling IPv6 i noted something strange. I don't know if docker has anything to do with this, it's just that i noticed this problem after ...
2
votes
0answers
114 views

How to verify network quality before running important benchmarks?

I have multiple CentOS servers around the world. They all are running a PHP script that tests the latency of some services once per minute. The problem is that sometimes these servers have local ...
0
votes
1answer
21 views

DHCPv6 CONFIRM message in Linux

I'm testing DHCPv6 client. One of the tasks I need to check is if the CONFIRM message is sent as described in RFC (if it occurs in specified timeout). I know that this message is sent to be sure if it ...
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2answers
29 views

Software to Detect Device Missing from Network?

I have several small Android tablets that I am going to deploy in a manufacturing environment. Each one will be assigned to an individual, but I'd still like to have some way of detecting if the ...
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0answers
16 views

Checking RadHuntGroup And Radgroupcheck to login specific NAS

I am actually setting up a FreeRADIUS Version 2.1.12, server that will manage authentication Users Cisco Switchs in company .. and i have one problem : I need to create some accounts that can be ...
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0answers
22 views

Bridge not functioning as expected

I want to put a listening machine in my test network using a bridge setup. I now have the following test setup: PC1 (192.168.40.250/24) --- Bridge (192.168.40.160/24) --- PC2 (192.168.40.132/24) ...
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0answers
27 views

SAVE default scope global nexthop in CENTOS 7

I have two internet connections from two different ISPs and I need to balance & failover the traffic originating to and from my network between the two ISPs. My settings: FIRST ISP (eno1): 152....
0
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2answers
86 views

Can a DNS server uniquely identify a specific client device behind a NAT?

I've been playing around with this Netflix Proxy setup (https://github.com/ab77/netflix-proxy), and I noticed that it might be possible to use the DNS endpoint to function like a hotspot with a walled ...
2
votes
1answer
53 views

On a host with multiple network interfaces, which interface resp. DNS server is used to resolve the hostname of the local machine (Windows)?

I am trying to answer the following question: What happens if a machine that has multiple network interfaces, gateways, and DNS servers (for example an interface for an Ethernet adapter and one for a ...
0
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0answers
28 views

VoIP NAT to connect to companies of the same ip address range together

I am currently using packet tracer to configure the network for Company A. I have configured DHCP and telephony service successfully but the problem I'm facing is when company A tries to contact ...
3
votes
2answers
558 views

802.3ad bonding configuration file on an Ubuntu 16.04 LTS Server

If I use a manual setup on the command line (following the kernel instructions), I can properly setup my network connection: # modprobe bonding mode=4 miimon=100 # ifconfig bond0 up # ip link set ...
0
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0answers
36 views

Public port forwarding from site A to site B (connected through a site-to-site VPN)

I have two distant offices (site A and site B). The two offices are connected through a site-to-site OpenVPN solution (the VPN servers are independent of the office routers, each router has a static ...
0
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1answer
22 views

Download Office before or after connecting computer to server?

I work at a small business with very limited access to IT support, so I apologize for having a "Servers for Dummies" question. I am trying to get several new computers as ready as possible to save ...
1
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0answers
14 views

rfc2307bis LDAP schema: ipNetmaskNumber lookup for an ipHost object

I'm using Openldap for IAM, and consider using it also as a configuration management backend. The rfc2307bis schema has an ipHost class, which allows for ipHostNumber attribute, but not for the ...
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1answer
63 views

OSPF port number

What does that mean "OSPF runs over IP as protocol number 89" as it bypassing transport layer using some socket?
-1
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1answer
89 views

extremly slow lan speed between the working station and the server [closed]

when you are transfer a file to our server it takes realy long time but when you are on the server and transfer a file from a drive to another it just do it immediately i had tried a ping test and ...
0
votes
1answer
32 views

Using a Gandi domain and a cloudfront default cert, how can I set up my CNAME records so that https works?

I have a website (www.foo.com), registered with Gandi. I have a static page on Amazon S3 (let's say s3.foo.us-west.com). I also have a Cloudfront distribution (foo.cloudfront.net). Originally, my ...
0
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1answer
19 views

Does adding more applications to a Citrix session increase network usage?

My understanding of the way Citrix works is that it basically sends screens from the server to the user at the other end. If the server has more applications running can it increase the amount of ...