Tagged Questions

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

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0
votes
1answer
64 views

Postfix config for backend webservers behind a load balancer [closed]

I've two web servers (ws1.example.com, ws2.example.com) with postfix installed locally as a mail rely (using mandrillapp), user access them via www.example.com, which is a load balancer On ws1, the ...
0
votes
0answers
87 views

TCP packets not reaching app, iptables dropping?

We are occasionally, but not consistently, experiencing a weird network stack issue. Rebooting the server in question clears it up. It happens as follows (gleaned through tcpdump on the server): ...
1
vote
2answers
92 views

Send Text String to a Socket In Windows

I have a server that has an open socket that listens for a particular text string on it in order to perform an action. Our linux machines send this data via: echo "text_string" | nc -w 2 ...
0
votes
1answer
67 views

dummy network interface in Linux

When i create a dummy network interface and then bring it up it show up being in UNKNOWN state: root@5b8dd2855a9c:# ip l a boom type dummy root@5b8dd2855a9c:# ip l show boom 58: boom: ...
2
votes
1answer
122 views

When cloning a VMware Virtual Machine, how can I prevent MAC address conflicts?

I've run into the following problem on both VMware Fusion (for Macs) and with VMware ESXi/vSphere. Many of you are familiar with the problem, and it is described at VMware KB: "Networking does not ...
0
votes
1answer
50 views

How to find out file path of file on a network share drive?

I am using a small .NET application which integrates a file into another application, however, I keep getting the following error in EventViewer (part of the .NET application): "The specified path, ...
0
votes
0answers
42 views

KVM virtual IP address not working on HOST, works on GUEST

I have a setup composed of the following: -> A HOST running KVM with the following network configs: # The loopback network interface auto lo iface lo inet loopback # The primary network interface ...
13
votes
2answers
2k views

What are the possible issues in using very short DHCP lease time (< 1min)?

We have a network setup for a demo, which lasts about 15mn. Our DHCP server is configured to assign ~ 100 addresses (max number of simultaneous connections or our AP) ... but since people might come ...
-5
votes
1answer
43 views

multiple servers running the same thing, how? [closed]

I have a little issue that I don't understand well enough to answer myself. Basically I have some servers on my home network, I am wondering how 2 servers could run something, lets say apache in this ...
1
vote
2answers
56 views

Allow only IPSEC outgoing traffic to a port (using IPTABLE?)

Problem: I've a situation where IPSEC server and the target server (Say http server) happens to be the same machine and I need allow ONLY the traffic coming through IPSEC server to have access to a ...
0
votes
0answers
12 views

Encapsulating VPN tunnels on Linux

I'm playing with python and networking and I want to write a program that allows me to select one of several VPN connections and encaspulate them within each other. That is to say, if I have VPN-A, ...
0
votes
0answers
32 views

NAT Traffic via my instance in Microsoft Azure

I'm working in Azure IaaS Environment I have a private network 172.16.0.0/16 in which I have few linux instances running (172.16.0.1-5) My instances are accessing the public internet on port 80 (so my ...
0
votes
0answers
31 views

Intermittent network failures, limited to certain client subnets

We've been seeing intermittent network failures. The failure mode tends to be that long running connections tend to drop out. We see it most with ssh and samba connections, although some occasional ...
-3
votes
1answer
33 views

What happens if all the ports of router(doing NAT) are occupied ? [closed]

Suppose n computer are connected to a router R .It is doing NAT but suddenly all of its ports are occupied .So when a new computer N tries to connect what would router do means it simple do not ...
0
votes
2answers
108 views

How to change the webgui password in pfsense from a console?

is there any way to change the password of the webgui administrator user in pfsense from my console? Just to mention i didn't locked my self out from the webgui. Regards, ankso
3
votes
8answers
266 views

Ping stops responding after the first line

I have a problem with the PING command on Windows 8.1. During a ping, the command returns no further output after sending the first ping request. For example: ping 192.168.1.200 Pinging ...
0
votes
2answers
35 views

Remote port forwarding through EC2 not working, though address is in use

I have a remote machine running a server which I'd like access to locally. However, I can only SSH into the machine, not use any other ports. I booted up an Amazon EC2 instances and opened all its ...
2
votes
1answer
95 views

Why to use fencing when you already have redundant communication links?

This article stays that you should use both fencing (aka STONITH) and redundant communication links. I'm trying to understand what benefits STONITH gives in case of split-brain. Consider for example ...
-1
votes
1answer
40 views

FTP upload slows down when devices are connected via hub [closed]

I have a setup with a network hub and three Ethernet devices. One of them is a PC (running windows XP), two others are hardware components that need to communicate with each other over the network. ...
-6
votes
3answers
38 views

How does Dynamic Dns works? [closed]

In order to access computer from anywhere we need ipaddress but as we know dynamic ip address changes frequently . To come up this issue Dynamic Dns is used .Can anyone please tell me how does it ...
-6
votes
1answer
43 views

How to access computer content using mac address? [closed]

I am making a project in which any one can have video on her pc and access it from anywhere also he can give access to another user so they can watch videos . But the problem is that how to uniquely ...
0
votes
3answers
102 views

EC2 instances in VPC and access to the Internet

I am playing a bit with AWS. I created one VPC (with 10.1.0.0./24 net) and two EC2 instances attached to it. One EC2 has 10.1.0.4, second 10.1.0.5 . I allocated one Elastic IP to VPC and associated it ...
0
votes
1answer
63 views

IPv4 Nating and IPv6 Bridging

We have only 5 usable static IPv4 IPs and many IPv6 static IPs. We want Multiple nodes/pc to be connected with Internet using nating/router because we have limited number of IPs. We would still want ...
1
vote
1answer
108 views

How to configure routing between Azure virtual networks?

I'm designing an Azure environment which will contain multiple virtual networks, and a requirement is for all networks to be connected; a VM in any network should be able to talk to another VM in any ...
-4
votes
2answers
80 views

How can NIC's remember the DHCP address past power off? [closed]

I have now seen an HP ProLiant DL385 G7 (573088-421) and HP ProLiant DL360p Gen8 both being able to remember the DHCP address for its NIC's even though I had powered off the server, and pulled the ...
0
votes
2answers
57 views

iptables to route/filter traffic by URL behind NAT

I have the following configuration: a DNS record of X.a.b.c pointing to an ip address I a DNS record of Y.a.b.c pointing to the same ip I. Internet---->(RT)--->(FW)--+-->(MN) ...
0
votes
1answer
39 views

Can we force dhclient to not renew ip rules?

I've overridden the ip routing rules on my RHEL machine by adding custom logic in a new script ifup-local that is run immediately after a new interface is attached. ...
0
votes
0answers
29 views

Most secure way to encrypt critical data to be shared, edited and seen (must ALWAYS be secure)

This question does not rely on time... so it's not about keeping data on tape or anything similar. I have 3 distinct PCs with critical information. PCs are running Windows OS. They all hold critical ...
0
votes
0answers
48 views

How to determine the cause of network issues of a hetzner.de dedicated server?

I've got 3 dedicated servers at hetzner.de, and I’m occasionally getting unavailability alerts for these servers, from 2 independent monitoring systems (New Relic and Pingdom) usually for all 3 server ...
0
votes
1answer
45 views

Restarting the networking on the HOST makes GUEST lose connection

I am probably missing something but have a KVM virtualized HOST/GUEST setup. The GUEST is using a bridge (br0) on the HOST for internet connectivity. When I make a "/etc/init.d/networking stop ; ...
1
vote
1answer
35 views

DropBox style folder storage

I would like to set up a storage for people to access. So like I have a network set up with 1 domain controller and a back up server as well and I have user accounts set up in AD and basically I want ...
0
votes
0answers
36 views

Cannot access centos7 application from remote computer

I have webmin installed on Centos 7 server. I can access webmin with lynx from localhost, but cannot access from remote computer (with crome). I can use ssh putty to connect to linuxbox. I tried ...
1
vote
0answers
31 views

How to access the setup wizard on Sonicwall TZ 100 firewall

I am trying to setup a TZ 100 firewall. I am following these instructions and I have attempted to follow these instructions: "Connect your computer to the LAN (X0) port on the SonicWALL. Connect an ...
0
votes
1answer
85 views

How should I bridge two networks, given each network has its own subnet & DHCP server?

I would like to join/bridge two different networks, network 1 and network 2: Network 1: A network consisted of a Linux box (with one ethernet) port and multiple clients (connected via LAN switch). ...
0
votes
1answer
81 views

Do ephemeral ports need to be open on the network firewall in order for nginx and sshd to work properly?

Preamble: So, before I actually ask the question, I'd like to point out that I'm somewhat apprehensive about posting this because even as I'm typing this out it it feels like I'm asking someone to ...
2
votes
3answers
140 views

Wireless network infrastructure for an office with 40 employees

In my company we're facing connectivity problems due to our not very professional network infrastructure. We're growing now, and we expect to be 40 people at the office by the end of the year. I'm ...
0
votes
1answer
98 views

No Ping/Telnet connection between VM

I am new in Azure and have one problem which I can not solve. I tried asking on StackOverflow, but - quoting - "You will have better luck asking on ServerFault". I want several Virtual Machines to ...
0
votes
1answer
55 views

Clients intermittently cannot reach internal server, Windows network with Watchguard XTM

Small business has internal Windows network on a single subnet 192.168.16.x. There is a Watchguard XTM 330 firewall appliance which routes traffic to the internet. Leased line. Some users are having ...
0
votes
2answers
41 views

Web proxying with 3rd party authentication

I have a typical website where users have to pay to sign up and access some premium content. This content are internal propietary web servers from different vendors (think of it like graphical ...
1
vote
1answer
352 views

ip route add works manually but throws “Error: an inet prefix is expected rather than …” when run via bash script

I'm trying to run a script that should add this route to a table 11: ip route add local 10.1.3.212 dev eth1 proto kernel scope host src 10.1.3.212 table 11 If I run this command manually, it is ...
1
vote
1answer
27 views

IIS Server only accesible on port 80 within network

I have an IIS 8 server running under Windows Server 2012. When it is accessed over port 80, I can access it from within the network. With an internal IP address of 192.168.1.14, I can go to ...
0
votes
0answers
21 views

Secondary floating IP on TUN/TAP interface

I'm currently working on a HA Cluster implemented using Corosync 2 and Pacemaker and I've run into a network limitation beyond my control that prevents me from implementing floating virtual IPs. Now ...
0
votes
0answers
22 views

Use tcpdump to find interface errors

I looking for what's causing dropped packets on an interface: RX packets:9064457 errors:0 dropped:4736 overruns:0 frame:0 TX packets:6388938 errors:0 dropped:0 overruns:0 carrier:0 I ...
0
votes
1answer
23 views

Openvpn, two tap network adapters

I have installed openvpn client on my pc (windows 7) and I have two tap network adapters. In this way I can open two openvpn connections at the same time. What I would like to understand is how it's ...
1
vote
0answers
45 views

TCP Window Size Allocation, TCP Window Zero Errors and Network Latency

My mind is about to explode as everyone is always blaming the network guys for disconnections and slowness in the networks, but Solarwinds Reports that all utilization in the network devices and links ...
1
vote
0answers
57 views

Using my IPs on OVH server via GRE

I can't route my IPs into a OVH server, can you help me to find the problem? Mikrotik GRE IP: 192.168.55.10 OVH Server GRE IP: 192.168.55.20 GRE iface name: ali1_fr1-ovz1 IP to route from Mikrotik to ...
2
votes
2answers
76 views

Method to log amount of transmitted data per each IP address in linux

I am looking for a method in linux to log the amount of data transmitted (received and sent separately) for every single IP address to which the data was sent to or received from. These statistics ...
0
votes
1answer
61 views

Network traffic simulation with one computer

I have a Linux box with a gigabit Ethernet interface in a local network. With this single computer, I need to simulate HTTP traffic like if it was coming from 20 machines (hence with 20 different IP ...
0
votes
1answer
65 views

Different throughput Ethernet-Wireless Wireless-Ethernet

I've built an open source implementation of RFC2544 to test IPv4 network devices. One of the first devices I tested is a wireless router D-Link 2640B. In order to measure its performance I use a ...
0
votes
0answers
153 views

Windows computer with static IP and 169.254 APIPA address

I have a Windows7 Pro computer being used as a server to control our IP cameras. Recently, it refuses to connect to any of the cameras, even though the cameras themselves are working. I can access ...