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

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14 views

route vpn over wifi when ethernet is first priority

I have a very special problem and google couldn't help me so far. I usually connect to the Internet via ethernet (en3). For some applications etc I need a wifi connection (en1). So my service order ...
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2answers
235 views

How is a TCP request routed from a virtual machine to an outside resource and back again?

Scenario: Computer A has a local ip of 192.168.1.100, which is running a VM inside of it. The VM now makes a tcp request to an external IP address (74.125.225.98). Could someone explain how the ...
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23 views

Difficulty sharing physical ethernet device with Xen 4.4

I have a virtualized PowerEdge T320, with a Ubuntu Server 14.04 running Xen 4.4 as host, that I use at my lab to do scientific computations (I'm the admin of the machine). This server has two physical ...
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0answers
7 views

Short-circuited ethernet wiring? Cable tester loop [migrated]

Ethernet at the place I rent was dead, and since I noticed the wire was terminated in "reverse" 568 B standard, I bought crimper and cable tester to fix it. However, there is still NO connection ...
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0answers
11 views

issue with QSFP+ to 4x SFP+ cable

I have a Gigabyte MD60-SC0 motherboard which has a QSFP+ port. I need to connect this with another machine I have which has a Intel X520-SR2 NIC (with two SFP+ ports) plugged in. I also have QSFP+ to ...
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1answer
32 views

Unable to access network on Windows Server 2012 (Ethernet)

We have a server that had been using Ethernet, but temporarily Wi-Fi, and is now using Ethernet again. Strangely, it will not connect to the Internet. It detects when a cable is plugged into the port ...
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0answers
26 views

Debian ethernet interface goes down while streaming video

While streaming video FROM a debian box to the rest of a network, I regularly see the ethernet interface go down on this box after a couple hours of streaming and it doesn't come back up until the box ...
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3answers
161 views

Why is cat6 required for long cable runs?

I'm glancing over a Ubuiquiti airFiber radio starter guide and it says "outdoor shielded 5e or above cabling should be used for all wired Ethernet connections. Category 6 is required for ...
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2answers
50 views

TCP/UDP Small Package Size optimization [closed]

I currently have the problem, that when a LOT of RTP streams (>800) go to one server the max. speed is onlynabout 70-80 Mbit (on a Gigabit LAN - all Hardware components are Gigabit components) 130 ...
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0answers
25 views

Dell PE2900 seeing only 1/2 ethernet controller

I have 2 ethernet controller on my dell poweredge 2900 : http://www.dell.com/downloads/emea/products/pedge/en/pe2900_Spec_Sheet_Quad.pdf But I only see one on my linux system : $ ip addr 1: lo: ...
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1answer
68 views

What is the difference between an Up MEP and a Down MEP for Ethernet OAM CFM?

I'm having trouble understanding the functional difference between an Up MEP and a Down MEP in CFM applications. Some sites say they are defined based on network direction, others seem to think they ...
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1answer
75 views

How do I increase the ring parameters for a NIC on a Linux server

I used the ethtool utility to increase the rx and tx values for the NIC on one of our servers. I ran the following command: ethtool -g eth0 Ring parameters for eth0: Pre-set maximums: RX: ...
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1answer
70 views

Any benefit and/or risk in enabling Jumbo Frames for the DAG replication network?

Exchange 2013 DAG, two nodes, a dedicated GBE network interface on each server for replication traffic, connected to a GBE switch, using a dedicated VLAN. Is there any benefit to Exchange replication ...
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1answer
19 views

How to fix non-working ethernet under Linux, with RX permanently increasing?

I have a system with the latest Linux Mint. An ethernet cable which yields internet with no special action from me under Windows 8.1 is detected under Linux, but does not seem to work. Running ...
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1answer
62 views

Connect access switches to router or core switch

My workplace consists of 4 access unmanaged network switches from three different computer rooms connected to a router. The router contains three 100mbps ethernet ports and one Gigabit (GigE) port. ...
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1answer
50 views

Is it possible to tell whether I am connecting to fast or gigabit ethernet with CAT5e cable?

My NIC supports gigabit ethernet: $ ethtool eth0 Settings for eth0: Supported ports: [ MII ] Supported link modes: 10baseT/Half 10baseT/Full ...
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1answer
58 views

Does the IP -> Ethernet multicast address mapping ambiguity matter for IGMP snooping switches?

There are 2^28 possible IP multicast addresses, but only 2^23 possible Ethernet (MAC) multicast addresses (http://technet.microsoft.com/en-us/library/cc957928.aspx), which is why e.g. 224.1.1.1 gets ...
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1answer
102 views

OpenVPN cannot connect to local machine that has two NIC cards

This is my first time EVER posting to these forums. Most of the time when I have an issue I can usually solve them by searching forums/Google. But this one issue has me stumped! My company just ...
2
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1answer
57 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
100 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 ...
2
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1answer
239 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?
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1answer
77 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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1answer
104 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 ...
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1answer
1k 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 ...
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1answer
20 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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2answers
333 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?
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0answers
101 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 ...
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1answer
93 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 ...
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3answers
620 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 ...
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1answer
49 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?
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2answers
147 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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2answers
415 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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43 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 ...
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1answer
21 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
124 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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1answer
66 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
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1answer
296 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 ...
6
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1answer
454 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 ...
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2answers
1k 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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1answer
98 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
178 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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4answers
159 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 ...
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1answer
42 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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0answers
61 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 ...
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2answers
60 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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168 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 ...
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1answer
246 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
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2answers
79 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
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0answers
2k 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
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3answers
547 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 ...