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

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22 views

VMXNET3 nic loses the ability to update ARP table after N hours

I have a fedora 18 VM that stops updating the arp table on eth1 after running for a number of hours to days. There are other VMs on the same hypervisor that can access all of the same networks without ...
0
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1answer
39 views

Improving “first copy” timing to distant data center?

Background: Our production rollouts comprise of below high-level steps. Take golden copy of code from single staging source. Stage code to multiple datacenters. Modify the staged code to have ...
0
votes
2answers
28 views

what does `pipe <number>` mean in `ping` output?

While running a test to diagnose some alleged network problem, I got this output from ping: --- r01c01b11n02 ping statistics --- 30000 packets transmitted, 29995 received, 0% packet loss, time 6309ms ...
0
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1answer
27 views

Software for emulating networks and NAT

I am working on a software that I need to test with different types of NAT, and I would like to set up a test environment I can reconfigure in different NAT modes. I would like to have: ...
1
vote
1answer
34 views

“Destination Host Unreachable” and ARP returns no addresses over LAN

I am currently trying to setup LAN over two machines with a network mask of 255.255.255.0 however I am receiving the following message when trying to communicate between them both; [root@alpha ~]# ...
-2
votes
1answer
67 views

Windows 2008 R2 - No internet access with static IP [closed]

We had an internet outage and when the ISP resolved the problem, we ended up with a server that no longer has internet access unless we use DHCP. I replaced the network card, thinking it might ...
0
votes
1answer
31 views

use do,while to make loop for each network adapter

I want to get RX and TX from each network adapter, so to get RX and TX from one network adapter, i used this commands : cat /proc/net/dev | grep 'wlan0' |awk '{if ($2) print $2}' | awk -v ...
-1
votes
0answers
24 views

How to setup two networks on one Ubuntu server 14.04 [duplicate]

I have machine with two eth ports and I wish configure separate networks on them as mentioned below: eth0: ISP1 providing dynamic IP (default internet connection) eth1: Local network providing ...
0
votes
1answer
50 views

how to whitelist or deny “enable” mode IP address to cisco 3750 switch

I have a Cisco 3750 switch and I want to modify the allow/deny IP addresses that can access it in ssh and "enable" mode. Not sure how, and googling is nearly impossible to get this info it seems.
0
votes
0answers
14 views

Packet captures of OSPFv2 with HMAC-SHA1 (RFC5709)

I'm looking to get my hands on packet captures showing a hello packet from OSPFv2 configured to use HMAC-SHA1 for authentication, or to find software that supports such a mode that I could use to ...
0
votes
0answers
27 views

Routing through SonicWALL SSL-VPN and Cisco L3 Switch

In the image above, we use the SonicWALL NSA 3500 at our gateway and handle VPN with its SSL-VPN. Our Layer 3 Cisco switch is our core network switch and handles about a dozen VLANs. Most VLANs ...
1
vote
2answers
55 views

Spanning Tree Necessary With 2 Stacked Dell Managed Switches?

I have a PowerConnect 6248 and 6224P stacked with the 6248 acting as the managing switch. They're connected using the 48Gbps stacking module with 2 cables running between the switches. Do I need to ...
3
votes
3answers
99 views

Can a Hyper-V machine be made slower and/or emulate a slow network connection?

I need to reproduce an issue with a client-server asynchronous communication (a bunch of JavaScript AJAX vs. an OData api), seemingly caused by some race condition in the calculations when the server ...
0
votes
0answers
26 views

Can a 100Mbit switch throttle the internet connection?

We have a rather peculiar problem with internet speed in our office. Recently, we switched to a fiber-optic connection. We're supposed to have a 100Mbit connection (up and down). Here's how it has ...
4
votes
2answers
159 views

packets sent on virtual IP don't hit iptables rule

I have a virtual interface eth1:3 with IP address 222.192.124.3, I have set up an iptables rule to log packets coming on that interface using the interface's IP (I know iptables doesn't care about ...
0
votes
1answer
46 views

Connect Multiple Networks Wirelessly [closed]

I have a home network using a router to connect computers both wirelessly and with network cables. I also have another separate network about 10m away from my home network that is networked via ...
0
votes
1answer
26 views

Can't Reinstall Solarwinds 9.2 after installing 10.9.1 Trial version

I am having an issue I am hoping someone can help me with. I own a copy of an older version of solarwinds 9.2, I decided I wanted to give the new solarwinds version a try so I decided to download it. ...
1
vote
1answer
66 views

Telnet Results in “Connection closed by foreign host”

I'm not a networking guy, so I apologize if my question is dumb. I have two Ubuntu machines setup on Amazon EC2. I need to "talk" from one to the other via port 9300. On my receiving machine, I ran ...
0
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0answers
24 views

XenServer Host with single NIC

The Citrix documentation speaks volumes about NIC bonding, separating management and VM data, but is it so terrible to run a XenServer host with only a single NIC? The server that we have access to ...
0
votes
1answer
29 views

Difference of HP network adapter types?

HP have a special type of cards they call FlexibleLOM, and I can't figure out what the differences are of the following HP Ethernet 10Gb 2-port 530FLR-SFP+ Adapter HP Ethernet 10Gb 2-port ...
0
votes
1answer
41 views

Can't connect to 2 different Linux computers via VNC (local network)

I have a problem connecting to Vino VNC server with 2 Linux Computers running Xubuntu. The computers are Based on the ODroid U3 chip which is ARM based. When both of the ODroids are on the same ...
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votes
3answers
62 views

How to find out capacity for network interfaces?

I could get the capacity for the network interface by lshw, but which file in sysfs is this information stored(i.e. which file in /sys/class/net/eth0/device/ directory)? $ sudo lshw -class network ...
0
votes
0answers
9 views

Reproduce netperf TCP_RR test with NTttcp

The documentation of NTttcp being hard to find and to understand, how can I mimic the behavior of the TCP_RR netperf test with NTttcp?
2
votes
2answers
54 views

Network Topology for Switch Redundancy

I am trying to improve redundancy we had our main switch go crazy and take down the network. I am looking to add another switch for redundancy. I am very unfamiliar with STP and if it is needed in ...
0
votes
0answers
23 views

Remote SQL Server Connection works from SSMS but not from Application

We are troubleshooting a weird issue with our SQL Server 2008 server. The application server runs a windows service that makes a DB connection via a connection string in its config file, and we end ...
0
votes
1answer
73 views

Linux tool to show connections/s?

Is there a tool/command to show connections per sec? I've tried a few iptraf and iftop but I can't see anything about connection rates.
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votes
1answer
15 views

Vagrant muulti-vm mode configure network

Does any one know how to configure multi-vm mode to be able to communicate each VM with others. I want to deploy client-server application and my VMs can't communicate by dns without adding hosts ...
0
votes
2answers
45 views

When emulating an OpenWRT Router in VirtualBox how do the network settings relate to a real world router?

I'd like to setup OpenWRT in VirtualBox for purposes of testing a network configuration before putting it on a live physical router. How do the adapter settings relate to the real physical ports on ...
0
votes
0answers
22 views

Sliverlight Media will not play within local network but will play from public

We have a website developed on ASP.NET that uses Silverlight to stream videos. All is working well when accessed externally, however, when accessed from the local network, it will not play the media ...
0
votes
0answers
24 views

Network setup issue with no connection between virtual machines

I have the following network setup: EDIT: NOTE: WARNING: In the above Windows1 should have the ip 192.168.137.1 The issue that i am having is that every machine can ping and connect to every other ...
0
votes
1answer
22 views

ESX Packet Loss

I'd like to test my software with some amount of packet loss. I see that I can do this with pfSense in the traffic shaping. But that's a lot of hassle to set up and create a couple of extra virtual ...
-1
votes
1answer
42 views

How do I close ports in Linux for security reasons (KVM)? [closed]

I am going to set up a KVM virtualization server on CentOS. The host machine and several of the VMs will have a dedicated IP addresses. I'm going to need to close off unused ports and probably ...
0
votes
2answers
74 views

Why would a traffic flow be on a VLAN in one direction, but not the other?

I've seen PCAPS recently from three separate companies networks where two devices are configured to transmit traffic to each other over UDP, where one side sends a VLAN header on each packet, and the ...
0
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2answers
52 views

How to setup an automatic failover firewall?

We have an intern network of servers. In this intern network only one server has access to the internet and serves as route/firewall so that other server have also access to internet. Now we want to ...
0
votes
1answer
58 views

Network remapping with iptables and PPTP VPN

I have two different networks: Home network 192.168.1.0/24 A - Home PC (192.168.1.100) B - Home Router (192.168.1.1 lan ip - x.x.x.x public ip) Office network 192.168.1.0/24 C - File Server ...
1
vote
1answer
58 views

Bridging is breaking the server: KVM configuration

I'm pretty new to networking and just can't get my head around this. I'm trying to setup KVM-Qemu so I can run some virtual machines. The instructions I'm following are telling me to use eth0 and ...
0
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0answers
45 views

eth0 NIC Link is Down repeating message in kernel log

I've noticed since few days ago that same repeating kind of messages occurs and I positively can say that nothing was intentionally changed (installed/uninstalled) in that period. here's sample of ...
1
vote
2answers
58 views

Constant traffic from IP

I am receiving constant traffic from an IP. I have checked web server logs and found nothing. I have used IP tables to close port 80 with no success. Here is what I have extracted: TCPDump after ...
4
votes
1answer
102 views

Bind outgoing SOCKS-server traffic to a specific IP

At the office we get access to the web via a SOCKS server which is started with the command: ssh localhost -f -N -D *:8888. This server has 2 IPs (but only one network card): eth0 xx.yy.zz.1 eth0:1 ...
1
vote
1answer
33 views

network level of veth doesn't respond to arp

I decided to play with veth : create a veth pair and send a ping from one end to another. $ ip link add type veth $ ip addr add 192.168.99.1 dev veth4 $ ip addr add 192.168.99.2 dev veth5 $ ip link ...
-2
votes
1answer
35 views

Multi-subnet cluster with two default gateways?

I have a Windows 2012 failover cluster spanning two subnets. 10.0.1.0/24 and 10.0.2.0/24. I also have network 10.0.0.0/24 connected to machines in both subnets which has access to the Internet. If I ...
0
votes
2answers
66 views

Broadcast Domains & Subnetting for Performance

I had an interesting discussion on Facebook a few weeks ago with another network engineer, which went something like this: Me: I'd like to smack the person who thought it would be a good idea to ...
2
votes
1answer
78 views

Can't join Windows domain from different subnet

I have a lab with Windows Server 2008 R2 acting as a domain controller for domain win.testlab with IP address 10.0.1.1. I have several Windows Server 2012 VMs connecting to this domain within the same ...
0
votes
0answers
17 views

Connection is not persistent when using EVDO data card

I use a BSNL EVDO wireless data card. So, with this I cannot get my connection persistent i.e I cannot load Facebook, Gmail or Google search properly. If I enter a word and hit enter in Google search ...
0
votes
1answer
72 views

squid cache shutting down error

I am not a squid expert and I would like to ask you for your opinion. I have gateway running debian 7.1 wheezy with Squid 2.7.STABLE9-4.1 installed. Then I have a server running Windows 2000 (this one ...
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vote
0answers
56 views

Proper way of setting gateway outside of subnet on FreeBSD?

I have a VPS running FreeBSD 10 and it is located in OVH's BHS datacenter. The gateway for my VPS is not in the same subnet as my IP address and when I went to set the gateway the usually way, it ...
1
vote
2answers
81 views

How do I configure bridged networking for VMs

I'm setting up a KVM virtualization server in CentOS 6. How do I configure bridged networking? (I think I need network interface eth0 to be accessible to VMs) I have tried to follow this guide: How ...
1
vote
1answer
25 views

e1kexpress event log entries for constant NIC connection and reconnection

We were experiencing problems with one of our Windows 7 client applications that maintains a windows file share connection to a local server and it seemed to require lengthy application restarts ...
0
votes
1answer
44 views

Windows 2012 R2 Server network fails intermittently

I have 2 windows 2012 R2 servers in a production environment. Both are VM's and configured same with the ip address as different. I haven't recieved alert of any kind of network failure for one ...
0
votes
0answers
17 views

What should I consider when I plan a meaningful monitoring for SNMP Switch (SG200-50)

I am currently planning the monitoring of a switch and would like to consider beforehand what I need to be closely monitored in order to obtain errors and warnings are also useful. I have a Cisco ...