Ethernet is the most common set of standards for wired connections in local area networks.

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3answers
469 views

Is an Ethernet point to point connection without a switch real time capable?

In automation and control, it is commonly stated that ethernet can't be used as a bus because it is not real time capable due to packet collisions. If important control packets collide, they often ...
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2answers
983 views

Ubuntu Server, 2 Ethernet Devices, Same Gateway - Want to force internet traffic through 1 device (or at least allow it to work!)

I have a Ubuntu 10.04 Server with 2 ethernet devices, eth0 and eth1. eth0 has a static IP of 192.168.1.210 eth1 has a static IP if 192.168.1.211 The DHCP server (which also serves as the internet ...
2
votes
1answer
225 views

Is there a standard managed switch configuration protocol?

is there a vendor-independend managed switch configuration protocol e.g. for creating VLANs that can be run over TCP or serial port?
2
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1answer
30 views

Two LAN cables when using Remote Access Card?

I recently bought a HP MicroServer N54L and a HP Remote Access Card. Connecting to the server over a KVM viewer for BIOS setup etc. works fine, but when it comes to installing Ubuntu 14.04. the ...
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0answers
19 views

Can't seem to see local network on Wine

I'm trying to use Wine on Ubuntu to use a proprietary Windows program that looks for a proprietary device on the local network. I don't know where it's looking, which protocol, port or IP address it's ...
0
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0answers
22 views

No ethernet link with certain combination of devices and cables [migrated]

I have a problem that seems odd to me. I have a small patch panel in my home which is wired to various outlets. Until recently, I was running my router (an Asus RT-N66U) near the panel but am now ...
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1answer
43 views

What is the most proper way of wiring RJ45 for Cat6/LAN?

I currently know of three different wiring patterns for RJ45: T568A, T568B, and USOC. Simply put: Which is the best method for creating a Cat6 cable? From my research, it seems like I should use ...
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votes
1answer
94 views

ethernet switch makes network down [closed]

I have a D-Link 8-port Ethernet switch which was perfectly working. Since 2 days ago it makes the entire network down. The problem is when I disconnect the cables it runs again and after I connect ...
2
votes
1answer
83 views

e1000e Reset adapter unexpectedly / Detected Hardware Unit Hang

I have a Dell 1U Server with Intel(R) Xeon(R) CPU L5420 @ 2.50GHz, 8 cores running Ubuntu Server Kernel Version 3.13.0-32-generic on x86_64. It has dual 1000baseT networking cards. I have it set up to ...
5
votes
3answers
332 views

Gigabit uplink versus regular switch port

I have a 10/100/1000 24-port + 2 mini-GBIC ports switch which I have to link to other switches. Unfortunately, on the other switch all the mini-GBIC slots are taken up, so all I can do is link them ...
0
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1answer
661 views

dhcp-server + iptables: Can't share ppp internet connection

I had this configuration before, and it used to work well, but now I got a new server and I can't setup it to share the internet connection from ppp0. I'm on Debian testing. The client connects ...
0
votes
1answer
19 views

Why am I seeing prefixed/duplicated packets coming from a comcast device?

I'm looking at traffic my CPE from Comcast in Wireshark, and for every packet, there is an additional packet that is the exact same, except for 4 additional bytes at the beginning of the frame ...
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votes
4answers
70 views

Same static IP addresses to single static IP address communication [closed]

I have a server with 4 modules, and one Ethernet Port and an internal hub to assign these modules to, configured as below. Module 1: 192.168.10.1 Module 2: 192.168.10.2 Module 3: 192.168.10.3 ...
4
votes
2answers
2k views

testing signals on an ethernet cable

I work on escalators that use ethernet cables to send signals from "nodes" to a PLC. the only tool available is a Fluke multimeter. is there a way of reading these signal using the meter? or do I need ...
2
votes
1answer
146 views

Automatically acquire IPV6 address in CentOS 6

The network has fixed IPv4 address, and automatic acquired IPv6 address. Does anyone have an idea how to setup? Thanks a lot! I didn't use NetworkManager. The following is my setting, but it does not ...
3
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2answers
246 views

What does 'Si' mean with respect to network switches?

I am seeing references to Multilayer Switches with Si as in the network symbol below. What does the 'with Si' qualifier mean?
0
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1answer
53 views

Suddenly unable to obain IP address but eth0 port blinking rapidly

After a server restart, the server is unable to obtain an IP address through a wired ethernet interface, neither automatically nor manually. However the green light on the back of the machine where ...
0
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0answers
36 views

zeroshell unsupported onboard Intel Ethernet I217-V and I210

I recently installed zeroshell 3.0.0 on a machine with a supermicro motherboard that has 2 onboard ethernet cards. It seems that this version of ZS does not support both of ethernet. I've read from ...
6
votes
2answers
951 views

What is the clock frequency inside 10Gb and 100Gb Ethernet cards?

As I understand, a 10Gb Ethernet card is capable of putting 10Gb every second on (say) a fibre optics cable. Now naively, for this to happen in hardware, one will need a 10GHz clock running the ...
7
votes
3answers
1k views

What is, and what problems result in a 'carrier error'

I haven't found a really clear definition about what a 'carrier error' is within the context of the ifconfig output for a interface. I have been searching on Google and there really isn't a great ...
0
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1answer
41 views

Ethernet switch signal quality

Is there a (significant) signal quality difference between ethernet switches? n other words: A 1000base-t, do some switches allow longer cable runs than other switches?
3
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2answers
393 views

Should Carrier Ethernet traffic be encrypted?

I'm looking for a best practice answer. We have a 100Mb point to point Carrier Ethernet circuit between a corporate office and an offsite data center. Basically we have SQL traffic replicating to ...
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2answers
51 views

How can I change metric of public network in route table

In my windows 8.1 ENT [64 bit] machine I have 3 network adapters. Ethernet 1 is connected to public network and other 2 ethernet adaptors are connected to different internal networks. The problem is ...
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0answers
26 views

AR8151 eth0 heavy trouble

First I had really bad issue with network speed. There I got this good article: http://mindmapapp.blogspot.com/2012/01/use-atheros-ar8151-ethernet-card-on.html But now I have really crazy things ...
6
votes
1answer
244 views

Is it possible to detect rx+ rx- tx+ tx- wires with multimeter?

Is it possible to detect rx+ rx- tx+ tx- wires of an ethernet cable having only a part of cable with multimeter or somehow else? I mean the situation when you have just one side of the ethernet ...
0
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1answer
20 views

Use local Internet connection

I have a network split into through two ethernet segments through a virtual VPN hub. In the figure, blue is the part of the network that I control. My problem is due to the orange subnetwork, that ...
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1answer
100 views

Network latency caused by incorrect cable?

Our team recently setup a new network and now we are experiencing network latency issues. the flow of traffic is as such: modem -> router -> packet shaper -> cisco3750 switch from router to packet ...
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votes
1answer
63 views

Splitting Ethernet cable [closed]

I am looking for the best way to network my small business. I have an office where my router/modem are located, and then 2 more computers in another room. I can route Ethernet to this room with about ...
2
votes
0answers
97 views

Full MTU not utilized with jumbo frames enabled

I've been testing to see if I can get any benefit from enabling jumbo frames. I've set up two identical Dell R210 servers with Xeon quad core E3122 CPUs, 8G of RAM and Broadcom NetXtreme II BCM5716 ...
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3answers
2k views

Why does ethernet have a minimum frame size specified?

I think the minimum is 64 Bytes. Why is that minimum necessary?
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2answers
416 views

Connect two networks to a single server using its two ethernet ports

I have two separated local networks (two routers, each is connected to its ISP for the internet connection) and a server with two ethernet ports. The server is running a local website service which I ...
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vote
4answers
353 views

Open source tool monitor network

I am after an open source tool to monitor the network traffic of a small lan. I thought of wireshark but the amount of details it captures is massive. What I need is just a basic analysis of the ...
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1answer
69 views

Is that MAC-48 address valid: “01:23:4:56:78:9A” [closed]

Wikipedia states about MAC-48 string format: The standard (IEEE 802) format for printing MAC-48 addresses in human-friendly form is six groups of two hexadecimal digits, separated by hyphens ...
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2answers
126 views

Calculating required uplink capacity of network switch [duplicate]

Is there any common method (usable in practice) for estimating the uplink capacity of switch based on known number of users connected to this switch and the maximum internet speed they are allowed. ...
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votes
4answers
134 views

Which way up does an ethernet port go? [closed]

I've scoured the internet, but nobody seems to be able to decide whether RJ45 sockets should go with the release catch facing up or down. For instance, Netgear has their ports this way: But Cisco ...
0
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1answer
29 views

Broadcast stop via loopback kills bandwidth

Why does creating a broadcast storm by directly connecting two ports on a switch cause the bandwidth to all the other ports to cease?
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2answers
56 views

Is it possible to produce an unfair ethernet NIC?

The ethernet MAC protocol is based on CSMA/CD, which defines an algorithm for fair collision handling: If the NIC detects a collision, it sends a jam signal and enters binary exponential backoff: ...
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0answers
41 views

ZyXel ES-2024 - Mirrored port showing duplicated traffic

I have a ZyXel ES-2024 PWD switch. I would like a computer plugged into port 26 to see all traffic that passes through port 2, both inbound and outbound. I have configured port mirroring for the ...
0
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0answers
108 views

Ethernet link not detected under Linux 3.6.9, but is ok in 2.6.39

I have a custom Linux appliance with a 100M ethernet port. Under the 2.6.39 kernel, networking was never an issue. Autonegotiation worked just fine, as did network transfers. Now, with the newer ...
7
votes
1answer
690 views

Can a limited broadcast packet contain destination MAC address other than FF:FF:FF:FF:FF:FF?

Can a limited broadcast contain destination MAC address other than FF:FF:FF:FF:FF:FF? If the answer is true, could you provide an example of a protocol that uses a packet like this. Ok, to elaborate ...
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0answers
47 views

Ethernet takes too long to connect after system wake up (OS X) - how to diagnose this? [closed]

On all my OS X computers Ethernet takes a bit too long to connect after the system wakes up, usually 10-15 seconds, as opposed to 2-3 seconds for WiFi. The LED indicator on my Ethernet hub (edit: ...
0
votes
1answer
89 views

Restrict network connection to virtual machine alone-VMWare

Is there a way to restrict a Ethernet/Wifi Connection to the virtual machine alone and not to the host operating system? I am using VMWare workstation on windows with centOS and Ubuntu as my guest OS ...
3
votes
1answer
67 views

Is a DCB switch required for a FCoE setup?

I'm looking to play around with a test Fibre Channel over Ethernet (FCoE) deployment between 2 Xen servers and 1 storage server. Eventually I plan to replace our ageing NFS shared storage solution. ...
2
votes
0answers
766 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 ...
2
votes
3answers
273 views

Windows Server TCP sockets random disconnect: how to reproduce?

We rented 10 Windows servers from a large provider in Europe. They all work as expected. One server suddenly crashed and customer care found that both disks were broken. They replaced disks and also ...
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votes
1answer
71 views

Networking service not responding [closed]

Networking is going down on some of our machines. This is happening very randomly. Restarting networking is fixing the issue. I found the following in the kernel logs: Mar 19 18:19:05 <host> ...
0
votes
2answers
267 views

Connecting VoIP Phones to a Laptop

I'm trying to connect two VoIP phones to a laptop using the internal ethernet adapter and a usb-to-ethernet adapter. My configurations are as follows: Laptop eth0 - 121.1.2.1/24 Gateway - 121.1.2.4 ...
0
votes
2answers
86 views

Different speed on Internet connection by switching NICs. Can someone make sense of this?

I solved my Internet speed problem, but I'm still puzzled. I can't understand what happened. My scenario: a small intranet is connected to Internet through a Linux gateway that connects to a Cable ...
5
votes
9answers
6k views

Why does 1GBit card have output limited to 80 MiB?

I'm trying to utilize maximal bandwidth provided by my 1GiB network card, but it's always limited to 80MiB (real megabytes). What can be the reason? Card description (lshw output): description: ...
4
votes
1answer
178 views

Why 10GbE card cannot negotiate 10Gbit with Windows 2012R2?

The Problem I've got four identical blade servers. I've got Windows Server 2012 R2 on one blade and Xen on all the others. On the Windows-hosted server (only) the 10GbE NICs cannot negotiate ...